Affiliation:
1. Department of Pharmacology & Toxicology, College of Osteopathic Medicine Michigan State University East Lansing Michigan USA
2. Department of Pharmacy, Faculty of Medicine University of Prishtina “Hasan Prishtina” Prishtina Kosovo
Abstract
AbstractObjectiveSerotonin (5‐HT) infusion in vivo causes hypotension and a fall in total peripheral resistance. However, the vascular segment and the receptors that mediate this response remain in question. We hypothesized that 5‐HT7 receptors mediate arteriolar dilation to 5‐HT in skeletal muscle microcirculation.MethodsCremaster muscles of isoflurane‐anesthetized male Sprague‐Dawley rats were prepared for in vivo microscopy of third‐ and fourth‐order arterioles and superfused with physiological salt solution at 34°C. Quantitative real‐time PCR (RT‐PCR) was applied to pooled samples of first‐ to third‐order cremaster arterioles (2–4 rats/sample) to evaluate 5‐HT7 receptor expression.ResultsTopical 5‐HT (1–10 nmols) or the 5‐HT1/7 receptor agonist, 5‐carboxamidotryptamine (10–30 nM), dilated third‐ and fourth‐order arterioles, responses that were abolished by 1 μM SB269970, a selective 5‐HT7 receptor antagonist. In contrast, dilation induced by the muscarinic agonist, methacholine (100 nmols) was not inhibited by SB269970. Serotonin (10 nmols) failed to dilate cremaster arterioles in 5‐HT7 receptor knockout rats whereas arterioles in wild‐type litter mates dilated to 1 nmol 5‐HT, a response blocked by 1 μM SB269970. Quantitative RT‐PCR revealed that cremaster arterioles expressed mRNA for 5‐HT7 receptors.Conclusions5‐HT7 receptors mediate dilation of small arterioles in skeletal muscle and likely contribute to 5‐HT‐induced hypotension, in vivo.
Funder
National Institutes of Health
Subject
Physiology (medical),Cardiology and Cardiovascular Medicine,Molecular Biology,Physiology
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献