Vasoactive intestinal peptide fragment VIP10-28 and active vasodilation in human skin.

Abstract

A recent study reported the vasoactive intestinal peptide (VIP) fragment VIP(10-28) inhibited the rise in skin blood flow during heat stress. Our laboratory has reported that the nitric oxide (NO) pathway and histamine receptor-1 (H1)-receptor activation is common to both exogenous VIP-mediated dilation and active vasodilation (AVD). The present study aimed to further examine the specific role for VIP in AVD by using VIP(10-28) to antagonize VIP-mediated dilation in the presence of NO synthase (NOS) inhibition and an H1 antagonist. Study 1 (n = 12) examined whether VIP(10-28) antagonizes vasodilation to exogenous VIP via inhibition of NO-dependent mechanisms. Study 2 (n = 6) investigated AVD in skin sites receiving VIP(10-28) alone and in combination with NOS inhibition. Study 3 (n = 6) examined AVD in sites receiving VIP(10-28) alone and combined VIP(10-28) and H1 antagonism. Due to differences in our findings and those previously published, study 4 (n = 6) investigated whether an increase in baseline skin blood flow could result in a diminished rise in AVD. Red blood cell flux was measured using laser Doppler flowmetry, and cutaneous vascular conductance (flux/mean arterial pressure) was normalized to maximal vasodilation (28 mM sodium nitroprusside). VIP(10-28) augmented vasodilation to exogenous VIP (P < 0.05 vs. control) and hyperthermia (P < 0.05 vs. control). NOS inhibition had no effect on the augmented dilation during exogenous VIP or hyperthermia (P > 0.05). Similarly, H1-receptor antagonists had no effect on the augmented dilation during hyperthermia (P > 0.05 vs. VIP(10-28)). In study 4, percentage of maximal cutaneous vascular conductance was attenuated when baseline skin blood flow was elevated before whole body heating. Our results suggest that VIP(10-28) may be an unsuitable antagonist for examining a role for VIP-mediated dilation in human skin.

• Authors: Brad W Wilkins, Brett J Wong, Nathan J Tublitz, Gregg R McCord, Christopher T Minson
• Journal: Journal of applied physiology (Bethesda, Md. : 1985) (J Appl Physiol (1985)) Vol. 99 Issue 6 Pg. 2294-301 (Dec 2005) ISSN: 8750-7587 [Print] United States
• PMID: 16109832 (Publication Type: Clinical Trial, Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Peptide Fragments
• Vasoactive Intestinal Peptide
• vasoactive intestinal peptide (10-28)

Topics

• Adult
• Blood Flow Velocity (drug effects, physiology)
• Dose-Response Relationship, Drug
• Female
• Humans
• Injections, Subcutaneous
• Peptide Fragments (administration & dosage)
• Skin (blood supply, drug effects)
• Skin Physiological Phenomena (drug effects)
• Vasoactive Intestinal Peptide (administration & dosage)
• Vasodilation (drug effects, physiology)