VIP research has accumulated one of the most conceptually rich bodies of preclinical literature on multifunctional neuropeptides, with published studies examining the 28-amino-acid vasoactive intestinal peptide across VPAC receptor signaling, neuroinflammation, circadian biology, pulmonary biology, cardiovascular function, immune modulation, gastrointestinal motility, and bone biology. Supplied as VIP by Midwest Peptide, the compound is positioned as a research-grade reference tool for in vitro and animal-model investigation of neuropeptide signaling. This pillar reviews the published VIP literature in depth and serves as the hub for the VIP cluster.
Definition
- What is VIP?
- VIP (vasoactive intestinal peptide) is an endogenous 28-amino-acid neuropeptide of the secretin/glucagon superfamily. It is studied in preclinical models for vasodilation, immune modulation, circadian rhythm regulation, and pulmonary smooth muscle research through VPAC1 and VPAC2 receptor signaling.
For Research Use Only. VIP is intended exclusively for in vitro and preclinical research. It is not approved for human use, is not a drug, and should never be administered to humans or to animals outside of an authorized research protocol.
Quick Reference
- Sequence: 28 amino acids, HSDAVFTDNYTRLRKQMAVKKYLNSILN
- Receptor system: VPAC1 and VPAC2 (G-protein coupled receptors)
- Family: secretin/glucagon/VIP/PACAP superfamily
- Origin: First isolated from porcine intestine (Said and Mutt, 1970s)
- Common research areas: vasodilation, neuroinflammation, circadian biology, pulmonary, immune
- Distinctive feature: broad multi-system biology through VPAC receptor signaling
What Is VIP?
VIP is a 28-amino-acid neuropeptide with broad biological activity.
Key facts:
- Sequence: 28 amino acids in characteristic alpha-helical structure
- Receptor binding: VPAC1 and VPAC2 (related GPCRs)
- Tissue distribution: widespread (CNS, gut, lung, vasculature, immune)
- Endogenous compound: produced by neurons, immune cells, and other tissues
- Family member: secretin/glucagon/VIP/PACAP superfamily
The peptide is supplied for research use as a lyophilized powder (VIP).
Why VIP is distinctive
- One of the most studied neuropeptides
- Acts on multiple tissue systems
- VPAC receptor system has clear pharmacological tools
- Substantial cumulative literature
- Bridge between nervous and immune systems
Origins: Discovery and Naming
VIP was discovered in the early 1970s by Said and Mutt.
Discovery context
- Original isolation from porcine intestine
- Named for original observed activity (vasodilation in intestine)
- Sequence determined shortly after discovery
- Subsequent decades expanded the biological scope substantially
Why the name "vasoactive intestinal" matters
- Reflects original isolation source (intestine)
- Reflects original observed activity (vasoactive)
- Modern research has substantially expanded the scope
- The name persists despite broader biology
VIP is now understood as a multifunctional neuropeptide rather than a narrowly intestinal-vasoactive compound.
VPAC Receptor System
The VPAC receptor system is foundational to VIP biology.
VPAC receptor isoforms
- VPAC1, broad tissue expression
- VPAC2, more restricted distribution
- PAC1, primarily binds PACAP, but VIP has some affinity
VPAC receptor signaling
- G-protein coupled receptors (Gs primarily)
- Activate adenylate cyclase → increased cAMP
- cAMP-PKA signaling cascade
- Multiple downstream effectors
Why VPAC receptor diversity matters
- Tissue-specific receptor expression
- Selective agonists/antagonists allow mechanism dissection
- Cross-tissue effects through different receptors
- Combination research opportunities
For an extended discussion, see VIP receptor research and VPAC1/VPAC2 signaling models.
The Cell Press journal Cell Reports archives primary research on GPCR biology.
Related research: VIP Receptor Research: VPAC1 and VPAC2 Signaling in Research Models.
Mechanisms of Action
VIP has multiple mechanism contributors.
Major mechanism axes
- VPAC receptor activation, primary mechanism
- cAMP signaling, primary downstream
- Anti-inflammatory effects, through immune cell receptors
- Vasodilation, vascular smooth muscle effects
- Neuroprotection, via VPAC2 in many contexts
- Circadian modulation, in suprachiasmatic nucleus
How these mechanisms integrate
The mechanisms converge on integrated outcomes:
- VPAC receptor binding triggers cAMP signaling
- cAMP activates downstream pathways (PKA, others)
- Tissue-specific consequences depend on cell type
- Cross-tissue effects produce integrated biology
The integrated effect is broader than typical neuropeptides that target single systems.
Neuroinflammation Research
Neuroinflammation is a major VIP research area.
Neuroinflammation biology
- Microglial activation
- Astrocyte responses
- Cytokine production in CNS
- Blood-brain barrier effects
- Cross-overlap with neurodegenerative biology
VIP effects on neuroinflammation
Published research documents:
- Reduced microglial activation in CNS injury models
- Modulated cytokine expression in brain tissue
- Anti-inflammatory effects in neurodegenerative models
- Protected blood-brain barrier function
- Connections to neuroprotection
For an extended discussion, see VIP neuroinflammation research animal model studies.
The Frontiers in Cellular Neuroscience archives primary research on neuroinflammation.
Related research: VIP Neuroinflammation Research: Animal Model Studies.
Circadian Rhythm Research
VIP plays a critical role in circadian biology.
Circadian biology basics
- Suprachiasmatic nucleus (SCN) is master circadian clock
- VIP-expressing neurons in SCN are critical
- VIP synchronizes circadian timing across SCN
- Cross-tissue circadian rhythms depend on SCN
VIP in circadian biology
- Essential for circadian rhythm coordination
- VIP knockout disrupts circadian rhythms
- Endogenous VIP rhythms in SCN
- Circadian disruption research
Published circadian effects
- Modulated locomotor circadian rhythms
- Effects on phase-shifting paradigms
- Light-VIP interaction research
- Cross-tissue circadian coordination
For an extended discussion, see VIP circadian rhythm research and SCN pathway studies.
Related research: VIP Circadian Research: SCN Pathway Studies in Animal Models.
Pulmonary Research
The lung is a major VIP target tissue.
Pulmonary VIP biology
- VIP is abundant in pulmonary innervation
- Bronchodilation effects through VPAC receptors
- Anti-inflammatory effects in airways
- Surfactant biology connections
- Cross-overlap with asthma research
Pulmonary research models
- Asthma models (allergic airway inflammation)
- COPD-relevant models
- Pulmonary fibrosis (bleomycin)
- Acute lung injury
- Pulmonary hypertension
Published pulmonary effects
- Bronchodilation in airway preparations
- Reduced airway inflammation
- Modulated mucus production
- Pulmonary vascular effects
- Surfactant modulation
For an extended discussion, see VIP pulmonary research and respiratory model studies.
The Wiley Online Library pulmonary research collection archives primary research on lung biology.
Related research: VIP Pulmonary Research: Published Respiratory Model Studies.
Cardiovascular Research
Cardiovascular biology has substantial VIP connections.
Cardiovascular VIP biology
- VIP innervation of coronary vessels
- Vasodilation effects
- Cardiac muscle effects
- Cross-overlap with autonomic biology
Published cardiovascular effects
- Coronary vasodilation
- Modulated cardiac function
- Effects on cardiac ischemia-reperfusion
- Connection to cardioprotection
For an extended discussion, see VIP cardiovascular research and coronary vasodilation animal model studies.
Related research: VIP Cardiovascular Research: Coronary Vasodilation Animal Model Studies.
Immune Modulation Research
VIP is a major immune-regulatory peptide.
VIP immune biology
- Produced by immune cells (T cells, mast cells)
- VPAC receptors on immune cells
- Anti-inflammatory effects
- Effects on T cell differentiation
- Cross-overlap with autoimmunity research
Published immune effects
- Modulated T cell biology (favors regulatory phenotypes)
- Reduced macrophage inflammatory activation
- Effects on dendritic cell function
- Anti-autoimmune effects in disease models
- Modulated cytokine balance
Why immune research matters
- Immune dysregulation is research-relevant clinically
- VIP's immune profile is well-characterized
- Cross-mechanism with neuroinflammation
- Translation to autoimmune disease research
For an extended discussion, see VIP immune modulation research and T-cell macrophage literature.
The Frontiers in Immunology archives primary research on immune biology.
Related research: VIP Immune Modulation Research: T-Cell and Macrophage Literature.
Gastrointestinal Research
VIP is foundational in GI biology.
GI VIP biology
- Major neuropeptide in enteric nervous system
- Effects on smooth muscle relaxation
- Modulates intestinal secretion
- Anti-inflammatory effects in gut wall
- Cross-overlap with IBD research
Published GI effects
- Smooth muscle relaxation in GI tract
- Modulated GI motility
- Effects on intestinal secretion
- Reduced colitis severity in animal models
- Modulated GI inflammation
For an extended discussion, see VIP gastrointestinal research and gut motility/IBD models.
Related research: VIP Gastrointestinal Research: Gut Motility and IBD Models.
Bone and Cartilage Research
VIP has emerging bone biology research.
Bone VIP biology
- VIP innervation in bone tissue
- VPAC receptors on bone cells
- Effects on osteoblast and osteoclast function
- Bone remodeling biology
- Cross-overlap with arthritis research
Published bone effects
- Modulated osteoclast activity
- Effects on osteoblast function
- Bone remodeling in animal models
- Cartilage biology effects
For an extended discussion, see VIP bone and cartilage research and skeletal VPAC studies.
Related research: VIP Bone and Cartilage Research: Skeletal VPAC Studies.
Mechanism Deep Dive: Anti-Inflammatory Pathway
VIP's anti-inflammatory effects span multiple mechanisms.
Anti-inflammatory mechanisms
- NF-κB inhibition, through cAMP signaling
- Cytokine balance shift, favoring anti-inflammatory profile
- T regulatory cell promotion, favoring tolerance
- Macrophage polarization, favoring M2 (anti-inflammatory)
- Reduced TNF-α production, across multiple cell types
Why this matters
- Inflammation drives many disease processes
- Anti-inflammatory compounds with mechanism diversity are research-relevant
- VIP's profile combines multiple anti-inflammatory mechanisms
- Cross-translation to autoimmune research
Mechanism Deep Dive: Vasodilation
Vasodilation is one of VIP's original recognized activities.
Vasodilation mechanisms
- VPAC receptor binding on vascular smooth muscle
- cAMP elevation → PKA activation
- Reduced calcium sensitization
- Smooth muscle relaxation
- Dependent on intact endothelium in some contexts
Tissue-specific vasodilation
- Coronary, well-documented
- Pulmonary, relevant to pulmonary hypertension research
- Cerebral, relevant to migraine research
- Splanchnic, relevant to GI biology
- Genital, relevant to reproductive biology
Methodological considerations
- Isolated vessel ring preparations (gold standard)
- In vivo flow measurements
- Cross-species variability
- Endothelium-dependent vs independent
Pharmacokinetics and Stability
VIP handling has specific considerations.
Stability features
- Lyophilized powder is reasonably stable
- Aqueous solution is sensitive
- Cold-chain handling preserves activity
- Standard peptide handling considerations
Pharmacokinetic profile
- Short plasma half-life with peptidase metabolism
- DPP-IV degradation contributes to clearance
- Tissue distribution depends on route
- Modified analogs improve stability
Modified VIP analogs
- DPP-IV-resistant variants
- Lipidated forms for improved half-life
- Cyclic forms for stability
- Selective VPAC1 or VPAC2 agonists
These modifications inform research design when sustained activity is needed.
Sourcing and Research-Grade Considerations
The integrity of VIP research depends on quality.
What research-grade VIP should include
- Third-party COA (not self-issued)
- Mass spectrometry identity confirmation of the 28-residue sequence
- HPLC purity (typically above 98%)
- Endotoxin and microbial screening
- Lot identification
Common failure modes
- Sequence errors in the 28-residue chain
- Aggregation impurities
- Truncated sequences
- Material that does not match labeled identity
VIP supplied by Midwest Peptide is provided with third-party COA documentation.
For an extended discussion, see where to buy VIP peptide for research and the sourcing guide.
Related research: Where to Buy VIP (Vasoactive Intestinal Peptide) for Research: Sourcing Guide.
In Vitro and In Vivo Methodology
VIP research spans the methodological range.
In vitro work
- Cell culture systems with VPAC receptor expression
- Receptor binding studies
- cAMP measurement
- Functional assays in tissue preparations
Ex vivo tissue preparations
- Vessel ring preparations
- Tracheal ring preparations
- Intestinal smooth muscle
- SCN slice preparations
In vivo animal models
- Mouse and rat models, broadest in vivo data
- VPAC knockout mice, for receptor-specific research
- Disease-specific models, diverse applications
- Aged animal models, for aging research
Endpoint diversity
- Receptor-level: binding, cAMP
- Tissue-level: contraction, relaxation, function
- Whole-organism: inflammation, behavior, physiology
- Disease-relevant: histology, biomarkers
Research designs that integrate multiple methodological levels generate more interpretable data.
Comparator Research Compounds
The VIP literature includes comparison work.
Common comparators
- PACAP, closely related peptide, similar receptors
- Secretin, family member, GI-related
- Glucagon, family member, metabolic
- Other VPAC ligands, for receptor-specific work
Why these comparators matter
- Family relationships inform mechanism
- Cross-receptor selectivity research
- Combination research opportunities
- Translation to clinical research
Mechanism distinctions
| Compound | Primary receptor | Strongest research |
|---|---|---|
| VIP | VPAC1, VPAC2 | Multi-system |
| PACAP | PAC1 (also VPAC1, VPAC2) | Stress, neuroprotection |
| Secretin | Secretin receptor | GI biology |
| Glucagon | Glucagon receptor | Metabolic |
Specific Disease Models
VIP has been examined in diverse disease models.
Pulmonary disease models
- Asthma (ovalbumin sensitization)
- COPD (smoke exposure)
- Pulmonary fibrosis (bleomycin)
- Acute lung injury (LPS, hyperoxia)
- Pulmonary hypertension (hypoxia)
Inflammatory disease models
- Inflammatory bowel disease
- Rheumatoid arthritis
- Multiple sclerosis (EAE)
- Psoriasis-related models
- Autoimmune diseases broadly
Neurodegenerative models
- Parkinson's disease (6-OHDA, MPTP)
- Alzheimer's-relevant (Aβ, APP/PS1)
- Stroke (MCAO)
- Traumatic brain injury
Cardiovascular models
- Coronary ischemia
- Heart failure
- Cardiac ischemia-reperfusion
- Hypertension models
Metabolic models
- Diabetes-related
- Insulin resistance
- Energy balance research
These specialized contexts extend the cumulative literature.
Cross-Cluster Research Connections
VIP connects to multiple other research clusters.
Anti-inflammatory connections
- Selank cluster, immunomodulatory peptide
- BPC-157 cluster, gastrointestinal anti-inflammatory
- KLOW blend, KPV anti-inflammatory component
Neurological connections
- Semax cluster, neuroprotective peptide
- Selank cluster, neuropeptide research
- DSIP cluster, sleep-related neuropeptide
Gastrointestinal connections
- BPC-157 cluster
- Cross-mechanism gut biology research
Why cross-cluster research matters
- Cellular biology is integrated
- Mechanism-aligned compound combinations
- Combination research expands cumulative literature
- Cross-validation of findings
Reporting Standards
Reporting standards for VIP research have evolved.
Essential reporting elements
- Reference compound source, supplier, lot, COA
- Storage and handling conditions
- Reconstitution buffer and timing
- Administration route and dose
- Animals, species, strain, sex, age
- Receptor selectivity rationale (if relevant)
- Tissue preparation methods (for ex vivo)
- Statistical analysis plan
Why each element matters
- VIP is sensitive to peptidase degradation; storage matters
- Receptor expression varies across tissues
- Cross-study comparison requires complete reporting
- Reproducibility depends on these details
The Frontiers in Pharmacology archives primary research on peptide pharmacology methodology.
Time Course Considerations
VIP effects vary across timescales.
Acute effects (minutes to hours)
- Rapid receptor-mediated effects
- Initial cAMP signaling
- Acute physiological responses (vasodilation, bronchodilation)
Sub-chronic effects (days)
- Sustained anti-inflammatory effects
- Tissue remodeling responses
- Adaptive cellular responses
Chronic effects (weeks)
- Long-duration anti-inflammatory effects
- Cumulative tissue effects
- Adaptive system responses
Why time course matters
Studies sampling at one time point miss the dynamic profile. Multi-time-point designs generate more informative data.
Cross-Species Considerations
VIP research has been conducted across species.
Common research species
- Mouse and rat, broadest in vivo data
- Rabbit, selected applications
- Guinea pig, pulmonary research
- Pig, translational research
- Cell lines, broad in vitro use
Cross-species observations
- VIP biology is highly conserved across mammals
- VPAC receptor system is conserved
- Quantitative differences across species
- Translation to human biology supported
Combination Research
VIP has been examined in combination contexts.
Common combination contexts
- With other anti-inflammatory compounds, for enhanced effects
- With pulmonary research compounds, for combined effects
- With circadian-affecting compounds, for SCN research
- With other research peptides, for integrated effects
Why combination research matters
- Cellular biology is integrated
- Multi-mechanism approaches engage broader effects
- Combination research informs translational hypotheses
- Mechanism endpoints distinguish additive vs synergistic
Building a VIP Research Program
Research programs that include VIP benefit from structured approaches.
Inventory considerations
- Standardize sourcing to a single supplier
- Document storage and handling
- Match lots across experimental arms
- Plan inventory for the timeline
Research design integration
When adding VIP to a design:
- Match the application to research question
- Include receptor-specific endpoints if relevant
- Consider time-course sampling
- Plan combination versus single-compound arms
Combination strategy
Programs working in inflammation, pulmonary, or neurological research benefit from:
- Cross-compound mechanism familiarity
- Combination research designs
- Integrated endpoint frameworks
Open Research Questions
Several open questions remain in the VIP literature.
Mechanism questions
- VPAC1 vs VPAC2 selectivity in different contexts
- Cellular signaling beyond cAMP
- Cell-type specificity of effects
- Cross-species mechanism conservation details
Methodology questions
- Optimal dosing schedules
- Cross-species dose translation
- Pharmacokinetics across delivery routes
- Best comparator compounds
Application questions
- Effects in standardized clinical-relevant disease models
- Combination interactions with broader peptide landscape
- Long-duration effects
- Specialized tissue applications
These open questions create opportunities for new research.
Reproductive Biology Research
VIP has substantial reproductive biology connections.
Reproductive VIP biology
- VIP-immunoreactive neurons in genital tract
- Vasodilation effects on reproductive organs
- Modulated reproductive function
- Cross-mechanism with hormonal biology
Published reproductive effects
- Effects on penile erection (vasodilation)
- Modulated reproductive smooth muscle
- Effects on follicle development
- Cross-overlap with stress biology
Why reproductive research matters
- Erectile dysfunction is a major research area
- Female reproductive disorders
- Cross-translation to clinical research
- Mechanism connections to other physiology
Migraine Biology Research
Migraine biology has major VIP connections.
Migraine and VIP biology
- VIP is implicated in trigeminal pain biology
- Vasodilation in migraine
- Cross-mechanism with PACAP (closely related)
- Active research area
VIP migraine research
- Animal migraine models
- Trigeminal stimulation paradigms
- Vasodilation measurements
- Cross-validation with PACAP
Translational considerations
- PACAP-targeting therapies have advanced clinically
- VIP biology informs migraine mechanism
- Cross-receptor pharmacology
- Future research directions
Diabetes and Pancreatic Research
Pancreatic biology has VIP connections.
Pancreatic VIP biology
- VIP innervation of pancreas
- Effects on insulin secretion
- Modulated pancreatic exocrine function
- Cross-mechanism with metabolic biology
Published pancreatic effects
- Modulated insulin secretion
- Pancreatic blood flow effects
- Effects on pancreatic cell biology
- Cross-overlap with diabetes research
Why this matters
- Diabetes is a major research area
- VIP family connects to incretins (GLP-1, GIP)
- Cross-receptor family pharmacology
- Translation to clinical research
VIP Drug Development Considerations
Several considerations inform VIP-related drug development.
Limitations of native VIP
- Short plasma half-life
- Peptidase degradation
- Limited oral bioavailability
- Receptor desensitization concerns
Strategies addressing limitations
- Sustained-release formulations, pumps, depot injections
- Modified peptide analogs, improved stability
- Inhalation delivery, for pulmonary indications
- Combination with peptidase inhibitors, extended duration
- Alternative receptor agonists, small molecules
Clinical research considerations
- Indication-specific dosing
- Route selection by tissue target
- Receptor selectivity for tissue-specific effects
- Combination with other compounds
Animal Model Selection
Animal model choice affects VIP research outcomes.
Common research species
- Mouse, broadest in vivo data, genetic models available
- Rat, large body of behavioral and physiological data
- Guinea pig, particularly relevant for pulmonary
- Rabbit, selected vascular research
- Pig, translational research
Why species matters
- Receptor expression varies across species
- Disease model availability differs
- Translation to human biology
- Cost and logistics considerations
Best practices
- Match species to research question
- Cross-species replication when feasible
- Document species rationale
- Strain-appropriate baselines
Future Research Frontiers
Emerging areas in VIP research.
Active frontiers
- Selective VPAC1/VPAC2 agonists/antagonists, for mechanism dissection
- Modified VIP analogs, for stability and selectivity
- Single-cell biology, characterizing cell-type-specific responses
- Combination expansion, pairing with broader compound landscape
- Long-duration studies, chronic effects in disease models
- Translational studies, bridging preclinical to clinical research
VIP in Translational Research
VIP research spans preclinical and clinical contexts.
Clinical research areas
- Pulmonary hypertension
- Sarcoidosis
- Inflammatory bowel disease
- Migraine
- Various other indications
What preclinical research can establish
- Mechanism of action at molecular and cellular levels
- Tissue distribution and pharmacokinetic profiles
- Effects in standardized disease models
- Combination effects with related compounds
What preclinical research cannot establish
- Clinical efficacy in human disease populations
- Long-duration safety in human use
- Optimal clinical dosing
- Disease-specific clinical outcomes
VIP Peptide Family Biology
Understanding VIP requires family context.
VIP/PACAP/secretin/glucagon family
- Related sequences with conserved structural features
- Different receptors with overlapping pharmacology
- Cross-reactivity considerations
- Evolutionary biology
Family-specific receptors
- VPAC1, VPAC2, for VIP and PACAP
- PAC1, for PACAP primarily
- Secretin receptor, for secretin
- Glucagon receptor, for glucagon
- GLP-1 receptor, GIP receptor, GLP-2 receptor, related GPCR family
Why family biology matters
- Cross-reactivity affects mechanism interpretation
- Family-wide pharmacology informs research
- Combination research within family
- Cross-species family conservation
For broader incretin family research:
Mechanism Deep Dive: cAMP-PKA Cascade
The cAMP-PKA cascade is the canonical VIP signaling pathway.
cAMP signaling overview
- VPAC receptor activates Gs protein
- Gs protein activates adenylate cyclase
- Adenylate cyclase produces cAMP from ATP
- cAMP activates protein kinase A (PKA)
- PKA phosphorylates downstream targets
Major PKA substrates relevant to VIP
- CREB, transcription factor for many VIP effects
- Ion channels, for electrophysiological effects
- Smooth muscle proteins, for relaxation effects
- Inflammatory pathway components, for anti-inflammatory effects
Beyond cAMP-PKA
VIP signaling extends beyond classical cAMP:
- Epac signaling, alternative cAMP effector
- PI3K/Akt pathway, engaged in some contexts
- MAPK pathways, for proliferation effects
- Calcium signaling, in select cell types
Why mechanism diversity matters
The diverse downstream signaling explains VIP's broad biological effects across multiple tissue systems.
Mechanism Deep Dive: Receptor Desensitization
VPAC receptor desensitization affects research design.
Desensitization biology
- Receptor phosphorylation by GRKs
- β-arrestin recruitment
- Receptor internalization
- Receptor recycling or degradation
Implications for research
- Sustained VIP exposure may produce tachyphylaxis
- Pulse dosing may be more effective than continuous
- Desensitization affects translational interpretation
- Combination research with allosteric modulators
Methodological considerations
- Document dosing schedule effects
- Multiple time-point sampling
- Receptor expression analysis
- Functional response over time
Endogenous VIP Biology
VIP biology in the body provides physiological context.
Endogenous VIP sources
- Enteric neurons (intestinal)
- CNS neurons (multiple regions)
- Immune cells (T cells, mast cells)
- Other cell types in lower amounts
Endogenous VIP regulation
- Circadian rhythms in SCN
- Stress-induced changes
- Inflammation-related changes
- Aging-related changes
Why endogenous biology matters
- Physiological context for pharmacological studies
- Distinguishes endogenous from administered effects
- Cross-translation to clinical research
- Disease-related endogenous changes
Receptor Expression Across Tissues
VPAC receptor distribution informs research design.
VPAC1 expression
- Broad, found across many tissues
- Particularly high in: liver, kidney, lung, GI tract, immune cells, CNS
- Lower in: cardiac muscle, reproductive tissues
VPAC2 expression
- More restricted distribution
- Particularly high in: SCN, thymus, smooth muscle, some immune cells
- Lower in: most other tissues
Receptor selectivity research
- Selective ligands enable mechanism dissection
- Tissue-specific effects through specific receptors
- Combination research with selective tools
- Translation to therapeutic targeting
Modified VIP and Selective Agonist Research
Modified compounds extend VIP research.
Modified VIP analogs
- DPP-IV-resistant, extended half-life
- Lipidated, improved pharmacokinetics
- Cyclic, enhanced stability
- Truncated, shorter active fragments
- Substituted, modified key residues
Selective receptor ligands
- VPAC1-selective agonists for mechanism research
- VPAC2-selective agonists for SCN research
- Receptor antagonists for blockade studies
- Cross-validation of receptor function
Why modified compounds matter
- Address PK limitations of native VIP
- Enable selective receptor research
- Support combination research
- Translation to clinical research
Aging Biology Connections
VIP biology intersects with aging research.
VIP changes with age
- Modified VIP expression with age
- Altered VPAC receptor expression
- Changed circadian VIP biology
- Aging-related immune changes
Aging research applications
- Cognitive aging models
- Aging immune dysfunction
- Cardiovascular aging
- Cross-mechanism with broader aging compounds
Cross-cluster aging context
VIP aging research connects to:
Receptor Knockout Models
Genetic models inform VIP biology.
VPAC1 knockout mice
- Reduced VIP-mediated effects
- Phenotype includes growth and metabolic alterations
- Useful for receptor-specific research
- Cross-validation of VPAC1-mediated effects
VPAC2 knockout mice
- Disrupted circadian rhythms (most prominent phenotype)
- Reduced SCN coordination
- Used for circadian biology research
- Cross-validation of VPAC2-mediated effects
VIP knockout mice
- Disrupted circadian rhythms
- Immune dysfunction
- GI motility changes
- Combined VPAC1 and VPAC2 effects unmasked
Why genetic models matter
- Definitive mechanism testing
- Receptor-specific effect attribution
- Cross-validation with pharmacology
- Translation to receptor-specific therapeutics
VIP in Translational Pharmacology
VIP biology informs broader translational research.
Therapeutic targets emerging from VIP biology
- Selective VPAC2 agonists for circadian disorders
- VIP analogs for pulmonary indications
- Anti-inflammatory applications
- PACAP-related research informing migraine therapy
Cross-mechanism therapeutic strategies
- Combining VIP family compounds
- VIP plus other anti-inflammatory compounds
- VIP plus targeted disease therapies
- Multi-mechanism approaches
Why translation is research-relevant
- VIP biology has direct clinical translation
- Multiple disease areas could benefit
- Cross-receptor selectivity supports targeted therapy
- The cumulative literature supports clinical research
VIP and Aging Brain Research
Brain aging has VIP biology connections.
Brain aging changes
- Reduced VIP expression in aged brain
- Altered VPAC receptor expression
- Aging-related neuroinflammation
- Cognitive aging connections
VIP effects in brain aging
- Restored VIP biology in some research
- Modulated aging neuroinflammation
- Effects on cognitive aging
- Neuroprotective effects in aged brain
Why this matters
- Aging brain biology is research-relevant
- Cross-mechanism with broader aging compounds
- Translation to age-related disorders
- Combination research opportunities
VIP Research Quality Framework
Long-running VIP studies benefit from quality framework.
Quality elements
- Reference compound documentation
- Methodology rigor (receptor, function, disease)
- Sample size adequacy
- Blinding and randomization
- Pre-specified endpoints
- Cross-validation across paradigms
Common quality issues
- Single-paradigm conclusions
- Inadequate receptor characterization
- Cross-study heterogeneity
- Sex differences not addressed
- Insufficient time-course
Why quality matters
The VIP literature benefits from rigorous quality. Modern standards strengthen the cumulative literature. Research that addresses quality elements explicitly contributes more reliably.
Cumulative Research Impact
The cumulative VIP research has established the compound as one of the most extensively characterized neuropeptides.
What the literature has established
- Multi-pathway mechanism profile across VPAC receptors
- Cross-tissue activity across many systems
- Anti-inflammatory profile
- Cross-species mechanism conservation
- Multiple effective administration routes
What the literature continues to refine
- Receptor subtype-specific effects
- Cell-type-specific biology
- Long-duration effects
- Specialized clinical-relevant applications
Future directions
- Selective receptor pharmacology
- Single-cell biology
- Combination research
- Translational research expansion
For research programs developing new VIP work, the cumulative literature provides a strong foundation but also a high bar for novel contribution.
Quality Assurance During Research
Long-running VIP studies benefit from quality checks.
Quality assurance practices
- Periodic re-characterization
- Consistent supplier and lot
- Document handling deviations
- Match reference material across experimental arms
Why this matters for VIP
- VIP is sensitive to peptidase degradation
- Long-duration studies require sustained quality
- Cross-tissue research adds methodology complexity
- Reproducibility depends on consistent reference compound
Sex Differences in VIP Research
Sex differences are important in VIP research.
Sex-specific VIP biology
- Sex hormones affect VPAC receptor expression
- VIP effects on reproductive tissues
- Sex differences in immune biology
- Pulmonary biology has sex dimensions
Methodological recommendations
- Both sexes in research designs
- Sex × treatment interaction analysis
- Sex-specific reporting
- Cross-sex replication
Dose-Response and Pharmacology
VIP dose-response has specific characteristics.
Reported dose ranges
- In vitro: nanomolar to micromolar concentrations
- In vivo subcutaneous: variable µg/kg
- Inhalation: aerosol or instilled forms
- Effective doses depend strongly on application
Dose-response patterns
- Many endpoints show clear dose-dependent effects
- Higher doses may produce desensitization
- Some endpoints show biphasic responses
- Combination contexts may shift effective ranges
Pharmacological tools
- Selective agonists for VPAC1, VPAC2
- Receptor antagonists for blockade
- Modified analogs for stability
- Allosteric modulators emerging
VIP Family Pharmacology
The broader peptide family informs VIP research.
Family pharmacology
- VIP, VPAC1 ≈ VPAC2 affinity
- PACAP, PAC1 > VPAC1 ≈ VPAC2
- Secretin, secretin receptor selective
- Glucagon family, glucagon, GLP-1, GLP-2 selective
- Cross-reactivity, limited but present
Why family pharmacology matters
- Cross-validation of mechanism
- Combination research
- Receptor selectivity research
- Translation across family
PACAP and VIP shared biology
- Both bind VPAC1 and VPAC2
- PACAP additionally binds PAC1
- Cross-validation of effects
- Combination research within family
Specialized Research Topics
Several specialized topics extend the VIP literature.
Migraine research
- VIP effects on cerebral vasculature
- Trigeminal pain biology connections
- Migraine model research
- Cross-mechanism with PACAP
Reproductive biology research
- VIP effects in reproductive tissues
- Erectile function research
- Female reproductive biology
- Cross-mechanism with hormonal biology
Cancer biology research
- VIP receptor expression in some cancers
- Tumor biology connections
- Diagnostic applications
- Cross-cancer research
Diabetes research
- VIP effects on pancreatic biology
- Insulin secretion modulation
- Glucose homeostasis effects
- Cross-mechanism with metabolic biology
VIP in Multiple Sclerosis Research
MS research is one of VIP's notable applications.
MS biology basics
- Autoimmune demyelination
- T cell-mediated CNS damage
- Cytokine-driven pathology
- Treg cell deficiency
VIP effects in MS models
- Reduced EAE (experimental autoimmune encephalomyelitis) severity
- Modulated T cell biology in EAE
- Promoted Treg differentiation
- Reduced demyelination
- Connection to translation toward MS therapy
Why this is research-significant
- MS is a major neurological disease
- VIP's anti-inflammatory profile is mechanism-aligned
- Cross-validation across multiple labs
- Translational potential
VIP in Rheumatoid Arthritis Research
RA research is another major VIP application.
RA biology connections
- Inflammatory joint disease
- T cell and macrophage involvement
- Cytokine-driven pathology
- Cross-overlap with VIP's anti-inflammatory profile
VIP effects in arthritis models
- Reduced collagen-induced arthritis
- Modulated synovial inflammation
- Effects on T cell biology in joints
- Cross-mechanism with bone biology
VIP and Sepsis Research
Sepsis biology has VIP connections.
Sepsis biology basics
- Systemic inflammatory response
- Multi-organ dysfunction
- Cytokine storm
- High mortality
VIP effects in sepsis models
- Reduced mortality in sepsis models
- Modulated cytokine storm
- Protected organ function
- Anti-inflammatory mechanism alignment
VIP and Sleep-Wake Biology
Beyond circadian biology, VIP affects sleep-wake regulation.
Sleep-wake VIP biology
- VIP-SCN circuit affects sleep timing
- Cross-mechanism with sleep-promoting neurons
- Role in REM sleep regulation
- Connection to sleep disorders
Cross-cluster connection
VIP sleep biology connects to:
- DSIP cluster, sleep-related peptide
- Cross-mechanism sleep research
- Combination research opportunities
VIP in Skin Biology
Skin has substantial VIP biology.
Skin VIP biology
- VIP innervation in skin
- Effects on skin immune cells
- Modulated wound healing
- Cross-mechanism with dermal research
Published skin effects
- Effects on dermal immune cells
- Modulated psoriasis-related models
- Wound healing in some contexts
- Cross-mechanism with broader inflammatory biology
Cross-cluster connection
VIP skin biology connects to:
- GHK-Cu cluster
- GLOW blend
- Cross-mechanism dermal research
Cross-Talk with Other Neuropeptides
VIP interacts with multiple other neuropeptides.
Common interactions
- PACAP, receptor sharing
- Galanin, opposing effects in some contexts
- NPY, vasomotor opposition
- Substance P, inflammatory cross-talk
- CGRP, vasodilator cross-talk
Why these interactions matter
- Real-world neuropeptide biology is integrated
- Combination research engages multi-peptide biology
- Cross-mechanism research informs translation
- Therapeutic combination opportunities
Storage and Handling Considerations
VIP storage practices affect research integrity.
Lyophilized powder storage
- Long-term storage at low temperature
- Protect from moisture and light
- Avoid repeated freeze-thaw of stocks
- Use within shelf life
Reconstitution
- Use sterile aqueous diluent
- Document concentration and reconstitution date
- Cold-chain handling for stability
- Use within recommended post-reconstitution window
Stability factors
- Aqueous solution sensitive to peptidase contamination
- pH affects stability
- Avoid extreme temperatures
- Protein-binding agents can stabilize
VIP and Anti-Aging Research
VIP intersects with broader anti-aging research.
Anti-aging mechanism connections
- Anti-inflammatory effects (inflammaging)
- Cardiovascular protection (vascular aging)
- Cognitive aging support
- Cross-mechanism with other anti-aging compounds
Combination research
- VIP + NAD+ for combined effects
- VIP + SS-31 for cardiac aging
- VIP + glutathione for redox protection
- Cross-mechanism aging research
Why this matters
Aging biology is multi-mechanism. Compounds that engage multiple aging-relevant pathways are research-relevant. VIP's broad biology supports multi-mechanism aging research.
Inhalation Delivery Research
Pulmonary delivery is a notable VIP research area.
Why inhalation matters
- Direct delivery to lung tissue
- Local effects with reduced systemic exposure
- Relevant for asthma, COPD, pulmonary hypertension
- Cross-translation to clinical pulmonary delivery
Inhalation methodology
- Aerosol formulations
- Dry powder formulations
- Particle size considerations
- Deposition site selection
Published inhalation research
- Bronchodilation studies
- Anti-inflammatory effects in lung
- Pulmonary vascular effects
- Cross-validation with systemic effects
Research Peptides Referenced
- VIP, research grade vasoactive intestinal peptide, third-party COA
- Selank 10mg, anti-inflammatory neuropeptide for combination research
- BPC-157 10mg, for gastrointestinal cross-mechanism research
For complete sourcing details see the VIP sourcing guide.
Related Research Reading
Within the VIP cluster:
- VIP Receptor Research VPAC1/VPAC2 Signaling
- VIP Neuroinflammation Research Animal Model Studies
- VIP Circadian Rhythm Research SCN Pathway
- VIP Pulmonary Research Respiratory Model Studies
- VIP Cardiovascular Research Coronary Vasodilation
- VIP Immune Modulation T-Cell Macrophage Literature
- Where to Buy VIP Peptide for Research
- VIP Gastrointestinal Research Gut Motility/IBD
- VIP Bone and Cartilage Research Skeletal VPAC
Related clusters:
Not for human consumption. Research use only.
