One peptide identified as potentially contributing to maintaining physiological homeostasis is the Vasoactive Intestinal Peptide (VIP). Studies suggest it is derived from the intestinal region and may uphold the optimal operation of the gastrointestinal system.
Research suggests this is achieved by regulating peristalsis and exerting its potential antimicrobial properties within the gastrointestinal tract. In addition to its primary function, researchers speculate it may act as a vasodilator, immune modulator, and secretagogue. Therefore, asserting that this peptide may exhibit pleiotropic characteristics would be accurate.
In this comprehensive analysis of VIP (Vasoactive Intestinal Peptide), we will endeavor to elucidate its physiological impacts, providing insight into the significance of this peptide and its essentiality.
Scientists hypothesize Vasoactive Intestinal Peptide (VIP) is a neuropeptide that may play a significant role in various physiological processes.
VIP is a naturally occurring neuropeptide initially discovered in the gastrointestinal tract three decades ago. The compound consists of 28 amino acids, and subsequent research has suggested its presence in the central and peripheral nervous systems.[i]
VIP is a glucagon/secretin superfamily member primarily secreted from the pancreas, intestine, and central nervous system. Considering its ubiquitous distribution and endogenous secretion within organisms, the resultant impacts of this substance may be inherently pleiotropic.
VIP Peptide : Mechanism of Action
Due to its impact on multiple physiological systems, comprehending the mechanism of action of VIP can be quite challenging.
There have been three identified vasoactive intestinal peptide receptors (VIP), which are scientifically categorized as VPAC1, VPAC2, and PAC1. The VPAC1 receptor is predominantly expressed in immune system cells, including macrophages, monocytes, dendritic cells, microglia, and mast cells.
Studies suggest that VIP may impact these cells by binding to the VPAC1 receptor. The immune system cells may subsequently initiate the adenylate cyclase pathway, which may regulate the immune system by diminishing inflammation.
The PAC1 receptor, which serves as an additional receptor for VIP (vasoactive intestinal peptide), induces the activation of phospholipase C and protein kinase C in macrophages. This signaling pathway is recognized as the primary mechanism underlying the anti-inflammatory effects.[ii]
A scientific study has suggested that mice lacking VPAC2 and PAC1 receptors may have exhibited increased vulnerability to inflammatory disorders, indicating the involvement of VIP in regulating the immune response.[iii]
Research suggests VIP, short for vasoactive intestinal peptide, may be a potent vasodilator surpassing the potency of acetylcholine by a factor of 50-100. It may enhance nitric oxide synthesis, subsequently triggering vasodilation in blood vessels.
Studies conducted on animal subjects have also suggested that presenting VIP (Vasoactive Intestinal Peptide) into the coronary arteries may exhibit a dual effect. It may reduce coronary vascular resistance and enhance coronary blood flow. This mechanism guarantees continuous and adequate perfusion of blood to the heart.[iv]
Researchers speculate that one of the primary roles of vasoactive intestinal peptide (VIP) in the small and large intestines is to induce smooth muscle relaxation. Additionally, it may induce relaxation of the sphincter of Oddi, a muscular valve located in the pancreas, facilitating the passage of pancreatic enzymes into the small intestine.[v]
Scientists hypothesize Vasoactive intestinal peptide (VIP) may exert a direct inhibitory effect on the secretion of gastric acid and pepsinogen in the stomach while simultaneously promoting the secretion of pancreatic enzymes.
The suprachiasmatic nucleus (SCN), located within the hypothalamus, is pivotal in regulating circadian rhythm. Studies suggest VIP, also known as a vasoactive intestinal peptide, may exert regulatory control over the firing rate of this particular nucleus, consequently influencing the intrinsic biological rhythm of the organism.
VIP Peptide Properties
Given our current understanding of the mechanisms underlying the functioning of VIP (Vasoactive Intestinal Peptide), it is anticipated that establishing a correlation between its effects and the associated properties will be a relatively straightforward task.
VIP Peptide and Inflammation
VIP has been explored in laboratory settings within the context of chronic inflammatory conditions affecting the gastrointestinal tract, characterized by significant mucosal inflammation resulting in abdominal pain. Studies suggest VIP may exert anti-inflammatory effects and possibly relieve inflammation.
Research suggests that VIP may regulate joint inflammation by suppressing cytokine activity. Therefore, it may aid in regulating cartilage and bone degradation, a significant contributing factor in the development of arthritis.[vi]
VIP Peptide and Vasodilatation
Studies suggest VIP, or vasoactive intestinal peptide, may play a crucial role in maintaining the health of the lungs and the heart due to its potential to cause vasodilation. This physiological response occurs through the process of vasodilation, which facilitates the provision of sufficient blood flow to these specific organs.
Researchers speculate a potential vasodilatory property of the peptide may also confer positive impact on reproductive functioning.[vii] Researchers hypothesize that VIP, also known as a vasoactive intestinal peptide, may induce vasodilation in the blood vessels of the corpus cavernosum, a spongy tissue within the reproductive organ.
Click here to learn more about this peptide’s properties. Note that these are research peptides, strictly available only to researchers and educational institutions. They are strictly prohibited for personal use.
- [i] Said SI, Mutt V. Polypeptide with broad biological activity: isolation from small intestine. Science. 1970;169(3951):1217-1218. doi:10.1126/science.169.3951.1217
- [ii] Delgado M, Pozo D, Ganea D. The significance of vasoactive intestinal peptide in immunomodulation. Pharmacol Rev. 2004;56(2):249-290. doi:10.1124/pr.56.2.7
- [iii] Goetzl EJ, Voice JK, Shen S, et al. Enhanced delayed-type hypersensitivity and diminished immediate-type hypersensitivity in mice lacking the inducible VPAC(2) receptor for vasoactive intestinal peptide. Proc Natl Acad Sci U S A. 2001;98(24):13854-13859. doi:10.1073/pnas.241503798
- [iv] Robert J Henning, Darrell R Sawmiller, Vasoactive intestinal peptide: cardiovascular effects, Cardiovascular Research, Volume 49, Issue 1, January 2001, Pages 27–37, https://doi.org/10.1016/S0008-6363(00)00229-7
- [v] Bahri˙ Karaçay, M. Sue O’Dorisio, Vasoactive Intestinal Peptide (VIP), Editor(s): Helen L. Henry, Anthony W. Norman, Encyclopedia of Hormones, Academic Press, 2003, Pages 564-575, ISBN 9780123411037
- [vi] Jiang, W., Wang, H., Li, Ys. et al. Role of vasoactive intestinal peptide in osteoarthritis. J Biomed Sci 23, 63 (2016). https://doi.org/10.1186/s12929-016-0280-1
- [vii] Youssef, Jihad Georges MD1,2; Lavin, Philip PhD3; Schoenfeld, David A. PhD4; Lee, Richard A. MD5; Lenhardt, Rainer MD6; Park, David J. MD7; Fernandez, Javier Perez MD8; Morganroth, Melvin L. MD9; Javitt, Jonathan C. MD, MPH10,11; Jayaweera, Dushyantha MD12. The Use of IV Vasoactive Intestinal Peptide (Aviptadil) in Patients With Critical COVID-19 Respiratory Failure: Results of a 60-Day Randomized Controlled Trial*. Critical Care Medicine 50(11):p 1545-1554, November 2022. | DOI: 10.1097/CCM.0000000000005660
