VIP

What is VIP?

Vasoactive Intestinal Peptide (VIP) is a 28-amino-acid neuropeptide widely expressed in the central and peripheral nervous systems and in many endocrine and immune cells. It is a member of the secretin/glucagon peptide family and acts via two GPCRs: VPAC1 and VPAC2. VIP is studied as both a basic neuroscience tool and a research probe for receptor pharmacology.

Mechanism of action (preclinical evidence)

VIP signaling is mediated primarily through two G-protein-coupled receptors, VPAC1 and VPAC2, both of which couple to Gαs and elevate intracellular cAMP through adenylyl cyclase activation. VPAC1 is broadly expressed in lung, liver, intestinal epithelium, and on T-lymphocytes; VPAC2 is concentrated in smooth muscle, the suprachiasmatic nucleus (where it regulates circadian rhythm), and on multiple immune cell types. Upon receptor binding, the cAMP/PKA cascade leads to phosphorylation of CREB and downstream transcriptional changes that broadly favor anti-inflammatory and trophic outcomes. Within the immune system, VIP has been characterized as a 'master immunomodulator': preclinical studies report it suppresses Th1 pro-inflammatory cytokine production (IFN-γ, IL-2, TNF-α), promotes a tolerogenic dendritic-cell phenotype, induces regulatory T-cell expansion, and downregulates NF-κB activity in macrophages. In airway smooth muscle, VPAC2 activation drives bronchodilation - the basis for early clinical interest in VIP analogues for asthma and COPD. In neurons, VIP is a non-adrenergic, non-cholinergic (NANC) transmitter and acts as a neuroprotective factor in models of cerebral ischemia, traumatic brain injury, and neurodegeneration. The peptide also has direct vasodilatory effects on vascular smooth muscle, contributing to its name. The breadth of these effects reflects VIP's evolutionary role as an integrating signal between the nervous, immune, and endocrine systems.

Research applications

• VPAC1/VPAC2 receptor binding and selectivity studies
• Smooth muscle relaxation models (vascular and bronchial)
• Intestinal secretion and motility research
• Neuroprotection in stroke and traumatic brain injury models
• Immune modulation and Th1/Th2 polarization studies

Storage and handling

Store lyophilised VIP at -20 °C in sealed, light-protected vials. Reconstituted solutions are relatively unstable; single-use aliquots and protein-low-binding tubes are recommended for cell-based assays.

Regulatory status

VIP is a naturally occurring peptide. The synthetic form supplied by Peptra Labs is for laboratory research only and is not approved as a therapeutic agent in any major regulatory framework.

Frequently asked questions