VIP: Scientific Profile

Publicado el 12 de julio de 2026 · Actualizado el 28 de agosto de 2026

VIP (Vasoactive Intestinal Peptide, synonym Aviptadil; CAS 40077-57-4) is a 28-amino-acid neuropeptide of the secretin/glucagon superfamily, widely studied as a reference material for research. It acts as an agonist of the G protein-coupled receptors VPAC1 and VPAC2, elevating intracellular cyclic AMP. It is investigated in models of vasodilation, bronchodilation, and immunomodulation.

VIP (Vasoactive Intestinal Peptide), also known by the synonym Aviptadil when referring to the synthetic form, is a 28-amino-acid neuropeptide with molecular formula C147H238N44O42S, approximate molecular weight of 3325.85 g/mol, and CAS number 40077-57-4. It was originally isolated from the intestine, from which its name derives, although it is now known to be widely distributed in the central and peripheral nervous system, the gastrointestinal tract, the respiratory system, and the immune system. It belongs to the secretin/glucagon peptide superfamily, which includes secretin, glucagon, GHRH, PHI, and the closely related PACAP (pituitary adenylate cyclase-activating peptide), with which it shares considerable structural homology and shared receptors.

From a structural standpoint, VIP is a linear peptide whose carboxyl terminus is amidated, a common feature in neuropeptides that contributes to its stability and to its receptor affinity. Its sequence is highly conserved among mammalian species, reflecting its physiological relevance. It preferentially adopts a helical conformation in its central and carboxy-terminal portion when interacting with the membrane and with the domains of its receptors. Like many endogenous peptides, it has a short plasma half-life due to degradation by peptidases, an aspect that in the research setting has motivated the study of analogs, formulations, and sustained-delivery systems.

The mechanism of action of VIP centers on two class B (secretin class) G protein-coupled receptors: VPAC1 (VIPR1) and VPAC2 (VIPR2). Both receptors bind VIP and PACAP with comparable affinity, while the PAC1 receptor shows a preference for PACAP. Following ligand binding, these receptors couple mainly to the Gs protein, which stimulates adenylate cyclase, increases the intracellular concentrations of cyclic AMP (cAMP), and activates protein kinase A (PKA). This cascade explains much of the effects observed in experimental models: relaxation of vascular and bronchial smooth muscle, modulation of exocrine and endocrine secretion, and broad anti-inflammatory and immunomodulatory signaling. In immune systems, activation of VPAC1/VPAC2 in lymphocytes, macrophages, and dendritic cells has been associated in preclinical studies with a shift toward anti-inflammatory cytokine profiles and with the regulation of T-cell differentiation. VPAC1 tends to be expressed constitutively in lymphoid and epithelial tissues, while VPAC2 shows a more inducible expression and a prominent distribution in smooth muscle and certain nuclei of the central nervous system, including the suprachiasmatic nucleus, where VIP participates in the synchronization of circadian rhythms.

The documented research applications of VIP and of its synthetic form Aviptadil are broad and are supported by a body of evidence ranging from in vitro studies and animal models to clinical trials in humans. In the respiratory system, its potent vasodilatory and bronchodilatory activity has been explored in models of pulmonary hypertension, pulmonary sarcoidosis, and acute lung injury; Aviptadil has been the subject of clinical trials, including studies in the context of acute respiratory distress syndrome. In the cardiovascular system, VIP is investigated for its vasodilatory effects and its role in the regulation of vascular tone. In gastroenterology it is a key neurotransmitter of the enteric nervous system, where it mediates smooth muscle relaxation and intestinal secretion, and it has been studied in relation to motility disorders. In the neurological and immunological fields, its capacity to modulate neuroinflammation and immune responses has made it a tool of interest in preclinical models of inflammatory and autoimmune diseases. It has also been studied in the context of erectile dysfunction, taking advantage of its local vasodilatory action. It is important to emphasize that all of these lines correspond to scientific research and experimental models, and that the use of VIP outside the laboratory setting or of regulated clinical trials is not part of the scope of this material.

As for the level of evidence, VIP is one of the best-characterized neuropeptides of its class. Its receptor pharmacology, tissue distribution, and signaling cascade are solidly established in the literature, and its synthetic form Aviptadil has advanced to clinical trials in humans for various respiratory and vascular indications, although this should not be interpreted as an approved treatment or recommended as such. The main practical limitation in research is its short half-life and its susceptibility to enzymatic degradation, which conditions experimental design and the choice of route of administration. As a reference material for research, VIP is valuable precisely because of the robustness of its mechanistic basis, which allows experimental results to be interpreted within a well-defined signaling framework.