Captopril enhances cardiac vagal but not sympathetic neurotransmission in pithed rats.
The effect of captopril on neurally evoked bradycardia and tachycardia was investigated in pithed rats. Captopril enhanced the vagal nerve stimulation-evoked bradycardia. Angiotensin I reduced the vagal bradycardia, which was reversed by subsequent administration of captopril. Bradykinin did not affect the neurally evoked bradycardia. Captopril and angiotensin I affected neither the exogenous acetylcholine-evoked bradycardia nor the sympathetic nerve stimulation-evoked tachycardia. These results suggest that the interruption of angiotensin II formation by captopril causes less presynaptic inhibition of acetylcholine release via angiotensin II receptors without affecting cardiac sympathetic neurotransmission.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa 199-0195, Japan. y-takata@pharm.teikyo-u.ac.jp.
Yoshinobu
Y
Takata
Takanori
T
Arai
Shigeto
S
Suzuki
Junichi
J
Kurihara
Takashi
T
Uezono
Yoko
Y
Okubo
Hitoshi
H
Kato
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001919:Bradycardia / Q000188:drug therapy / Q000503:physiopathology; D002216:Captopril / Q000008:administration & dosage / Q000494:pharmacology*; D003655:Decerebrate State; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D009435:Synaptic Transmission / Q000187:drug effects; D013610:Tachycardia / Q000188:drug therapy / Q000503:physiopathology; D013997:Time Factors; D014630:Vagus Nerve / Q000187:drug effects* / Q000503:physiopathology
D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril