文档介绍：257 Ρ
Ρ-229) Effects of nicorandil on the isolated smooth muscle
preparation of the dog coronary artery. Tokumasa Tsukada,
Toyohiko Ushij ima, Mikio Nakazawa and Shoichi Imai. Department
of Pharmacology, Niigata University School of Medicine,
Niigata 951, Japan.
Effects of nicorandil on the canine coronary artery were
investigated with strips of the circumflex branch bathed in
physiological salt solution (PSS) buffered with tris
(hydroxymethy1) aminomethane (pH=)_^ aerated with oxygen and
kept at 37°C. Nicorandil (10-3x10 M) relaxed dose-
relatedly the contracture induced by lanthanum in the calcium
free, high Κ PSS(for the method, refer to Japan. J. Pharmacol.
31:221, 1981), as well as that produced by high Κ ()
PSS. Nitroglycerin relaxed both contractures also dose-
relatedly. The ratio of potency of nicorandil and nitrogly­
cerin was approximately one to thousand in both types of
experiments. Caffeine (8-25mM) produced a contraction of this
preparation in calcium free, high Κ PSS with 4mM of EGTA,
which could be completely abolished by lOmM of procaine,
suggesting that the contraction was due to a calcium-induced
calcium release from its intracellular storage site. The con­
traction was reversibly suppressed to 68±7% of the control by
nicorandil ( Μ), while nitroglycerin was without
effects, eve