VIP (Vasoactive Intestinal Peptide)
A 28-amino-acid neuropeptide studied for effects on vasodilation, immune regulation, circadian rhythm, and inflammatory disease research.
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What is VIP (Vasoactive Intestinal Peptide)?
Vasoactive Intestinal Peptide (VIP) is a 28-amino-acid neuropeptide first isolated from porcine intestinal tissue in 1970 by Said and Mutt at the Karolinska Institute. Despite its name suggesting an intestinal origin, VIP is widely distributed throughout the body, present in both central and peripheral nervous systems, in lymphoid tissues, in the gastrointestinal tract, and in the cardiovascular system. It belongs to the secretin/glucagon peptide family and shares structural similarity with glucagon, pituitary adenylate cyclase activating peptide (PACAP), and other peptide hormones.
VIP is notable in research for its functional breadth across multiple physiological systems. Its documented roles include vasodilation, bronchodilation, gastrointestinal smooth muscle relaxation, modulation of immune responses, regulation of circadian rhythms in the suprachiasmatic nucleus, and effects on neurotransmission and neuroprotection. A significant challenge in VIP research is the peptide’s extremely short half-life (approximately 2 minutes), which has driven development of VIP analogs with improved stability including aviptadil (synthetic VIP) and various PEGylated or modified versions investigated in clinical trials.
Mechanism of action
VIP’s mechanisms of action have been investigated across multiple pathways:
- VPAC1 and VPAC2 receptor activation: VIP acts through two G-protein-coupled receptors expressed on different cell populations, with VPAC1 widely distributed including in immune cells and VPAC2 having more restricted distribution including in vascular smooth muscle, brain, and certain immune cell subsets.
- cAMP-dependent signaling: Receptor activation leads to increased intracellular cAMP through Gs-coupled adenylyl cyclase activation, the primary signaling cascade through which VIP produces most of its physiological effects.
- Vasodilation and smooth muscle relaxation: Research has documented potent vasodilation through direct effects on vascular smooth muscle, with similar relaxation in bronchial, gastrointestinal, and genitourinary tissues.
- Immunomodulation: Studies have documented anti-inflammatory shifts in immune responses, including inhibition of inflammatory cytokine production (TNF-α, IL-12), promotion of regulatory T-cell function, and effects on dendritic cell maturation.
- Circadian rhythm regulation: VIP is critically important in the suprachiasmatic nucleus, the master circadian pacemaker in the brain, where VIP-expressing neurons coordinate cellular rhythms across the nucleus.
These pathways are characterized in both preclinical models and clinical research contexts.
Research applications
VIP has been investigated across several research domains, with the most active areas including:
- Pulmonary arterial hypertension research: VIP and aviptadil have been investigated for pulmonary arterial hypertension based on the peptide’s vasodilatory effects. Inhaled aviptadil progressed through clinical trials examining effects on pulmonary vascular tone.
- Sarcoidosis and granulomatous inflammation: VIP analog therapy has been investigated for sarcoidosis and other granulomatous inflammatory conditions, with research suggesting potential anti-inflammatory benefit through immune modulation pathways.
- Asthma and respiratory research: Inhaled VIP and analogs have been studied for asthma and chronic obstructive pulmonary disease, based on bronchodilator and anti-inflammatory mechanisms.
- Chronic inflammatory response research: VIP has been examined within specific research frameworks for chronic inflammatory response syndromes attributed to biotoxin exposure, with research interest focused on the peptide’s broad immunomodulatory effects.
- Neurological research: Research has examined VIP in various neurological contexts including circadian rhythm disorders, neurodegeneration models, and potential neuroprotective applications drawing on the peptide’s effects on neural tissue.
This compound is intended for laboratory research use only. It has not been approved for human therapeutic use by any regulatory agency.
Storage & reconstitution
In its lyophilized form, VIP tolerates ambient temperatures during shipping but should be stored long-term at -20°C, protected from light. The peptide is more sensitive to degradation than many other peptides, both as lyophilized powder and in solution. Properly stored lyophilized peptide remains stable for 24 months or longer.
Once reconstituted with bacteriostatic water for injection, VIP solutions should be stored refrigerated at 2-8°C and used within 28 days, with stability shorter than most peptides. Some research protocols use the compound immediately after reconstitution. Avoid repeated freeze-thaw cycles, which can degrade peptide structure and reduce activity.
Visual inspection should be performed before each use. The reconstituted solution should be clear and colorless. Reject any solution that appears cloudy, discolored, or contains visible particulate matter.
For step-by-step reconstitution calculations, see our reconstitution calculator.
For laboratory research use only. The compound described on this page is intended exclusively for in vitro research and laboratory experimentation by qualified researchers and is not for human or veterinary use. It is not a drug, food, dietary supplement, or cosmetic, and has not been approved by the FDA, Health Canada, EMA, or any other regulatory authority for the diagnosis, treatment, cure, mitigation, or prevention of any disease or medical condition. The information provided on this page is for educational and reference purposes only and does not constitute medical advice. By accessing this content you confirm that you are a qualified researcher purchasing for legitimate laboratory purposes.