Involvement of capsaicin-sensitive sensory nerves in early and delayed cardioprotection induced by a brief ischaemia of the small intestine.
Early cardioprotection can be achieved by a brief ischaemia of noncardiac tissues. Our study examined whether a brief ischaemia of the small intestine induces both early and delayed cardioprotection in the rabbit and assessed the possible mechanism involved in the activation of capsaicin-sensitive sensory nerves. The plasma concentration of creatine kinase (CK) and infarct size (necrotic zone/left ventricular zone) after 30 min coronary artery occlusion and 180 min reperfusion were determined in rabbits. Infarct size was 35.5+/-6.8% in the control non-preconditioned group. Preconditioning induced by a brief period of 10-min small intestine ischaemia significantly reduced infarct size (6.5+/-1.9%, P<0.01 vs. the control non-preconditioned group) and decreased CK release (3092+/-236 and 1094+/-117 U/l for myocardial ischaemia-reperfusion and preconditioning plus myocardial ischemia-reperfusion, respectively, P<0.01), and the protection was partly abolished by pretreatment with capsaicin (50 mg/kg, s.c.) 4 days before the experiments. A brief period of anterior mesenteric artery occlusion caused an increase in the plasma level of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI), an effect which was abolished by pretreatment with capsaicin. Similar protection was shown in the animals subjected to a brief period of anterior mesenteric artery occlusion 24 h before coronary artery occlusion, and this delayed protection was also abolished partly by pretreatment with capsaicin. Capsaicin treatment (50 mg/kg, s.c.) alone also protected the ischaemic myocardium. The results suggest that brief ischaemia of the small intestine induces both early and delayed protection against reperfusion-induced myocardial injury, and the effects are, at least partly, related to the activation of capsaicin-sensitive sensory nerves.
Tang
Z L
ZL
Department of Pharmacology, Hunan Medical University, Changsha, PR China.
Dai
W
W
Li
Y J
YJ
Deng
H W
HW
D000818:Animals; D002116:Calcitonin / Q000276:immunology; D015740:Calcitonin Gene-Related Peptide / Q000097:blood; D002211:Capsaicin / Q000494:pharmacology*; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D007118:Immunoassay; D007421:Intestine, Small / Q000098:blood supply*; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D008638:Mesenteric Arteries / Q000601:surgery; D009203:Myocardial Infarction / Q000473:pathology*; D009475:Neurons, Afferent / Q000502:physiology*; D011817:Rabbits; D015427:Reperfusion Injury / Q000517:prevention & control*; D013997:Time Factors
D002116:Calcitonin; D003402:Creatine Kinase; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin