Jpn. J. Pharmacol. 86 (2), 251-253 (2001)

Diltiazem Ameliorates Contractile Dysfunction Without Shortening of Action Potential Duration in Ischemic Heart of Anesthetized Dogs

Kaori Hamada1,*, Jun Yamazaki2 and Taku Nagao1

1Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
2Department of Pharmacology, Fukuoka Dental College, Sawara-ku, Fukuoka 814-0193, Japan

*Corresponding author. Present address for correspondence: Medicinal Biology Research Laboratories, Fujisawa Pharmaceutical Co., ltd., Yodogawa-ku, Osaka 532-8514, Japan
FAX: +81-6-6304-5367, E-mail:

Abstract: The purpose of the following experiment was to determine whether amelioration of myocardial contractile dysfunction by diltiazem is mediated by shortening of monophasic action potential duration (MAPD) during myocardial ischemia in anesthetized dogs. Diltiazem improved regional contraction during reperfusion after 10-min occlusion. The shortening of MAPD and increase in [K+]e were blunted by treatment with diltiazem. These results suggest that shortening of action potential duration during myocardial ischemia is unlikely to be a reason for the amelioration of contractile dysfunction.

Keywords: Diltiazem, Ischemic heart, Action potential duration
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