Title

Dopamine relaxes porcine coronary arteries and stimulates potassium channel activity in porcine coronary arterial smooth muscle cells

Document Type

Article

Publication Date

2000

Abstract

The relaxing effect of dopamine on isolated coronary vessels and the activating effect of dopamine on large-conductance, calcium-activated potassium channels (BKCa) in the membrane of coronary myocytes were investigated with isometric tension recording method and patch-clamp technique. Tension studies demonstrated that dopamine relaxed prostaglandin F2α-induced contraction of porcine coronary arteries in a concentration-dependent manner, but it failed to relax high [K+] precontracted arteries. In cell attached patch experiments, dopamine caused a significant increase in the mean opening probability of the BKCa channels. The effect of dopamine was not blocked by propranolol but was completely prevented by SCH23390, a selective DA1 antagonist. These results demonstrate that dopamine relaxes prostaglandin F2α-induced contraction of porcine coronary arteries via activation of DA1 receptors which causes stimulation of BKCa channel activity.

Publication Title

Chinese Journal of Pharmacology and Toxicology

Volume

14

Issue

6

First Page

421

Last Page

424

Comments

This article was published in Chinese Journal of Pharmacology and Toxicology, Volume 14, Issue 6, Pages 421-424.

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