title: On the mechanism of the protective effects of nitroglycerin and nicorandil in cardiac anaphylaxis.
abstract: Previous investigations have shown that nitric oxide donors and nicorandil can suppress allergic reaction. In the present study, the protective effects of nitroglycerin and nicorandil on cardiac anaphylaxis were examined. Presensitized guinea-pig hearts challenged with specific antigen caused a marked decrease in coronary flow (CF), left ventricular pressure (LVP) and its derivatives (+/-dp/dtmax), increase in heart rate, and prolongation of P-R interval. Nitroglycerin (300 nM) or nicorandil (100 microM) markedly increased the content of calcitonin gene-related peptide (CGRP) concomitant with a significant improvement of the cardiac dysfunction and alleviation of the extension of P-R interval. Nicorandil at a concentration of 100 microM also inhibited the sinus tachycardia and histamine release. The protection afforded by nitroglycerin was abolished by glibenclamide, a blocker of ATP-sensitive potassium channels, or by CGRP8-37, the selective CGRP receptor antagonist, or by pretreatment with capsaicin, which depletes endogenous CGRP. The inhibitory effect of nicorandil on cardiac anaphylaxis was abolished only by glibenclamide but not by pretreatment with capsaicin. These results suggest that nitroglycerin and nicorandil possess a protection of cardiac anaphylactic injury. The present study also suggests that the protective effect of nitroglycerin may be related to stimulation of CGRP release and opening the KATP channel, and that the effect of nicorandil is mainly due to the activation of the KATP channel.
authors.affiliation: Department of Pharmacology, Hunan Medical University, Changsha, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Xiao
authors.forename: Z H
authors.initials: ZH
authors.lastname: Zhou
authors.forename: F
authors.initials: F
authors.lastname: Ye
authors.forename: H W
authors.initials: HW
authors.lastname: Deng
authors.forename: Y J
authors.initials: YJ
authors.lastname: Li
mesh_terms: D000707:Anaphylaxis / Q000517:prevention & control*; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D004347:Drug Interactions; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D020108:Nicorandil / Q000627:therapeutic use*; D005996:Nitroglycerin / Q000627:therapeutic use*; D015221:Potassium Channels / Q000187:drug effects; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D015221:Potassium Channels; D014665:Vasodilator Agents; D020108:Nicorandil; D005996:Nitroglycerin; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin; D005905:Glyburide