Korean J Physiol Pharmacol.  1999 Dec;3(6):587-595.

Effects of calcium channel blockers on porcine cardiac and coronary arterial function in ischemia-reperfusion

Affiliations
  • 1Department of Pharmacology, Chonnam University Medical School, Kwangju, Korea.
  • 2Research Institute of Medical Sciences, Chonnam University Medical School, Kwangju, Korea.
  • 3Department of Pharmacology, College of Medicine Chosun University, Kwangju 501-191, Korea.

Abstract

This study was designed to investigate effects of calcium antagonists on endothelial and neuronal dysfunction of right coronary artery (RCA) induced by ischemia- reperfusion in anesthetized, open-chest pigs. After reperfusion, pigs were sacrificed and the RCA was rapidly dissected for in vitro experiments. Experimental groups were divided into 4 groups: control (C-RCA), ischemia-reperfusion only (I-RCA), verapamil infusion (VI-RCA) and nifedipine infusion (NI-RCA) group, respectively. The ischemia did not affect hemodynamics, mean arterial pressure, heart rate, LVdP/dtmax, and decreased RCA flow. Arterial pressure and heart rate during ischemia-reperfusion were decreased in VI-RCA and NI-RCA, and RCA flow during reperfusion was increased in NI-RCA. 5-Hydroxytryptamine (5-HT) produced concentration-dependent contractions in C-RCA. The 5-HT-induced contractions were potentiated in I-RCA and VI-RCA, but not in NI-RCA. Endothelium-dependent relaxation by calcium ionophore A23187 was inhibited in I-RCA and VI-RCA, and recovered in NI-RCA. Cyclic GMP contents were decreased in I-RCA group alone. Electrical field stimulation in C-RCA produced transient and frequency-dependent contractions and at 50 Hz caused biphasic contractions. The transient contractions were not affected by pretreatment with phentolamine and atropine, but the biphasic contraction was altered by the pretreatment. Both contractions were inhibited in I-RCA, and were partially recovered in VI-RCA and NI-RCA. Ischemia-reperfusion of RCA in pigs causes endothelial and neuronal dysfunctions, and calcium antagonists partially prevent both.

Keyword

Calcium antagonist; Porcine coronary artery; Ischemia; Reperfusion; Endothelial dysfunction

MeSH Terms

Arterial Pressure
Atropine
Calcimycin
Calcium Channel Blockers*
Calcium Channels*
Calcium*
Coronary Vessels
Cyclic GMP
Heart Rate
Hemodynamics
Ischemia
Neurons
Nifedipine
Phentolamine
Relaxation
Reperfusion
Serotonin
Swine
Verapamil
Atropine
Calcimycin
Calcium
Calcium Channel Blockers
Calcium Channels
Cyclic GMP
Nifedipine
Phentolamine
Serotonin
Verapamil
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