[Pharmacological properties of pteleprenine, a quinoline alkaloid from Orixa japonica (Rutaceae), in guinea pig ileum and canine left atrium].
We investigated the pharmacological properties of pteleprenine, a quinoline alkaloid contained in the Rutaceous plant, Orixa japonica, on the contractile responses of the guinea pig ileum and on the inotropic responses of the canine left atrium. Contractile responses of the ileum to acetylcholine and histamine were not inhibited by less than 10(-6) M of pteleprenine. Meanwhile, the nicotine induced-contraction of the ileum was dose-dependently diminished by pteleprenine, but the contractile response to nicotine did not reach the maximum value in the presence of 10(-5) M of pteleprenine. The pA2 value of pteleprenine was 6.6 as determined from the Schild plot, which slope was nearly unity. Furthermore, the contraction of the ileum by 10(-5) M of 1,1-dimethyl-4-phenylpiperazinium (DMPP), a specific agonist of nicotinic acetylcholine receptors, was also dose-dependently suppressed by pteleprenine. On the other hand, 10(-5) M of pteleprenine did not have considerable inhibitory effects on acetylcholine- and nicotine-induced negative inotropic effects in the canine left atrium. From these results, it is suggested that pteleprenine has a specific inhibitory effect on nicotinic acetylcholine receptors in the guinea pig ileum.
Murata
K
K
Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
Seya
K
K
Miki
I
I
Junke
H
H
Motomura
S
S
Oshima
Y
Y
D000470:Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D006224:Cricetinae; D004149:Dioxoles / Q000302:isolation & purification / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D006325:Heart Atria / Q000187:drug effects; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D018727:Muscarinic Antagonists; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D018733:Nicotinic Antagonists; D015363:Quinolones / Q000302:isolation & purification / Q000494:pharmacology*
D000470:Alkaloids; D004149:Dioxoles; D004365:Drugs, Chinese Herbal; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D015363:Quinolones; C111713:pteleprenine