Ischemic preconditioning mediated by calcitonin gene-related peptide in isolated rat hearts.
OBJECTIVE
To study the mediating effect of calcitonin gene-related peptide (CGRP) in ischemic preconditioning in the isolated perfused rat heart.


METHODS
Isolated rat hearts were subjected to 3 cycles of a 5-min ischemia and a 5-min reperfusion before a 30-min global ischemia followed by a 30-min reperfusion.


RESULTS
Ischemic preconditioning caused an improvement of heart functions, reduced the incidence of ventricular arrhythmias and decreased the release of creatine kinase (CK) during reperfusion (CK activities = 0.30 +/- 0.07, 2.03 +/- 0.49, and 0.92 +/- 0.40 U.min-1/g wet wt for control, ischemia-reperfusion, and preconditioning, respectively). However, pretreatment with CGRP8-37 (0.1 mumol.L-1) abolished the improvement of cardiac contractivity, the reduction of the incidence of arrhythmias, and the inhibition of CK release by preconditioning (CK activities = 0.9 +/- 0.4 vs 2.55 +/- 0.32 U.min-1/g wet wt, P < 0.01).


CONCLUSIONS
CGRP is an endogenous myocardial protective substance that played an important role in mediation of ischemic preconditioning.
Xiao
Z S
ZS
Department of Pharmacology, Hu-nan Medical University, Changsha, China.
Li
Y J
YJ
Deng
H W
HW
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D003402:Creatine Kinase / Q000378:metabolism*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D010446:Peptide Fragments; C058636:calcitonin gene-related peptide (8-37); D003402:Creatine Kinase; D015740:Calcitonin Gene-Related Peptide