VIP: Vasoactive Intestinal Peptide Research Overview

VIP was isolated in 1970 by Sami Said and Viktor Mutt at the Karolinska Institute, working with porcine duodenal extracts in research on intestinal hormones. The peptide was named for its prominent vasodilatory activity, though subsequent research established that vasodilation is just one of many biological actions in animal models.^[1]

VIP is a member of the secretin/glucagon superfamily of peptide hormones, which share sequence similarity and structural features. Other family members include secretin, glucagon, GLP-1, GLP-2, PACAP, and PHI. The shared evolutionary origin produces overlapping but distinct receptor pharmacology across the family.^[2]

VIP is studied as a research reference compound in preclinical neuropeptide pharmacology, immunology, and cardiovascular research. It has not been approved by the FDA for any human therapeutic or medical purpose.

VIP structural features:

• Sequence: His-Ser-Asp-Ala-Val-Phe-Thr-Asp-Asn-Tyr-Thr-Arg-Leu-Arg-Lys-Gln-Met-Ala-Val-Lys-Lys-Tyr-Leu-Asn-Ser-Ile-Leu-Asn-NH₂ (28 residues with C-terminal amidation)

• Length: 28 amino acids

• C-terminal amidation: present

• Net charge: highly basic at physiological pH

• Molecular formula: C₁₄₇H₂₃₇N₄₃O₄₃S

• Molecular weight: approximately 3,326 Da

VIP shares strong N-terminal sequence similarity with secretin, glucagon, and other family members. The N-terminal region is essential for receptor activation, while the C-terminal region determines receptor selectivity within the family.^[2]

VIP and PACAP (pituitary adenylate cyclase activating peptide) are particularly closely related, sharing approximately 68 percent sequence identity. The two peptides engage the same VPAC receptors with similar affinity, making receptor selectivity studies particularly challenging.

VIP engages two main G-protein-coupled receptors.

VIP binds both VPAC1 and VPAC2 receptors (also called VIPR1 and VIPR2) with similar affinity. These are class B GPCRs that signal through Gs to produce cAMP accumulation downstream. PACAP also binds these receptors, plus a third PAC1 receptor that is PACAP-selective.^[3]

VPAC1 and VPAC2 have distinct tissue distributions. VPAC1 is expressed in lung, intestine, and T-lymphocytes. VPAC2 is found in smooth muscle, thymus, and certain regions of the central nervous system. The two receptors mediate different aspects of VIP biology depending on tissue context.^[4]

VIP research is extensive given the peptide's broad biology.

VIP's vasodilatory effects in animal vascular preparations were the original research observation that gave the peptide its name. Smooth muscle relaxation assays and intact animal cardiovascular endpoints are standard substrates.^[5]

VIP has well-characterized effects on immune cell function, including modulation of T-cell responses and cytokine production. Cell culture studies of immune cell preparations have used VIP as a tool compound for examining these pathways.^[4]

VIP is widely distributed in the central and peripheral nervous systems and serves as a research tool for examining secretin-family neuropeptide signaling more broadly.^[6]

VIP is a relatively large peptide with multiple basic residues that contribute to solubility. Standard peptide handling applies.

Lyophilized VIP is stored at minus 20 degrees Celsius for long-term preservation. Brief refrigerated storage is acceptable.

Bacteriostatic water is the standard reconstitution solvent. The basic peptide is readily water-soluble.

HPLC for purity, mass spectrometry for identity confirmation matching the 28-residue amidated mass, and endotoxin screening. Each batch of Instant Peptides VIP ships with a full Certificate of Analysis.

Instant Peptides supplies VIP as a synthetic lyophilized reference compound. Material is supplied to qualified research professionals. Not for human or animal consumption.

View the product page for current pricing and the Certificate of Analysis for the active batch.