Effect of luteinizing hormone-releasing hormone on the mechanical activity of the guinea-pig cardiac muscle.
1. The inotropic effect of physiological concentrations of luteinizing hormone-releasing hormone (LH-RH) in isolated guinea-pig cardiac muscles was studied. 2. LH-RH increased the contractile force elicited by either fast and slow responses in a dose-dependent manner. 3. These effects of LH-RH were affected by phentolamine and diltiazem but not by propranolol and cold condition. 4. This study showed the positive inotropic effect of LH-RH on myocardium through the affection to intracellular Ca, and the difference from the effect of cardiotonic steroids.
Hasegawa
J
J
Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.
Saitoh
M
M
Hirai
S
S
Fukuki
M
M
Kotake
H
H
Yoshida
A
A
Shigemasa
C
C
Mashiba
H
H
D000818:Animals; D004110:Diltiazem / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D013696:Temperature
D007987:Gonadotropin-Releasing Hormone; D011433:Propranolol; D004110:Diltiazem; D010646:Phentolamine