Regional variations of vasomotion to G-protein coupled receptor agonists following heat stress in rats

• DOI: 10.1211/jpp.62.03.0005
• Publication Date: 2010-10-14T13:20:47Z
• Authors: Jie Li; Yong-Xiao Cao; Kun-Lun Chen; Lei Cao; Zhao Ma; Cang-Bao Xu
• Keywords: Male; 0301 basic medicine; Neurotransmitter Agents; Receptors, Endothelin; Calcitonin Gene-Related Peptide; Osmolar Concentration; Arteries; In Vitro Techniques; Heat Stress Disorders; Muscle, Smooth, Vascular; Mesenteric Arteries; Rats; Receptors, G-Protein-Coupled; Serotonin Receptor Agonists; Femoral Artery; Rats, Sprague-Dawley; 03 medical and health sciences; Renal Artery; Organ Specificity; Vasoconstriction; Animals; Adrenergic alpha-Agonists

AbstractObjectivesThis study was designed to compare vascular contractile and relaxing responses to G-protein coupled receptor agonists among the different regions of arteries following heat stress in rats.MethodsHeat exposure was performed by increasing the internal temperature of the rats to 42°C for 15 min. After heat stress for 48 h, a myograph system was used to monitor the contractile responses in rat renal, femoral and mesenteric arteries to agonists of endothelin type B (ETB) receptor, endothelin type A (ETA) receptor, serotonin receptor and α-adrenoceptor, respectively. In addition, calcitonin gene-related peptide (CGRP)-induced vasodilation was studied.Key findingsThe results showed that heat stress induced decreased contractions mediated by α-adrenoceptors and serotonin receptors (at lower concentration), while it increased contraction mediated by endothelin ETB receptors and enhanced relaxation mediated by CGRP receptors in the renal artery. Heat stress increased contractions mediated by endothelin ETB receptors, endothelin ETA receptors and α-adrenoceptors in the femoral artery. In the mesenteric artery, heat stress increased contractions mediated by endothelin ETB and serotonin receptors and relaxation mediated by CGRP receptors.ConclusionsThe vasomotor responses to the G-protein coupled receptor agonists with altered vascular contractions and relaxations were different in rat renal, femoral and mesenteric arteries after heat stress. This might have contributed to the redistribution of blood flow and aids understanding of the preconditioning phenomenon.