Biphasic relaxation caused by electrical field stimulation of the mesenteric arteries of rats.
Electrical field stimulation (EFS) caused biphasic relaxation, first transient and then sustained, of rat mesenteric arteries precontracted by prostaglandin (PG) F2alpha. The transient relaxation was reduced about 45%, and the sustained relaxation was not observed after endothelium denudation of the arteries. N(omega)-Nitro-L-arginine (L-NOARG) inhibited the biphasic relaxation induced by EFS. At 1 - 100 microM, L-NOARG inhibited the transient relaxation more than the sustained relaxation. Methylene blue inhibited the biphasic relaxation and at 100 microM, L-NOARG abolished the transient relaxation. These results suggest that the transient relaxation mainly involves nitric oxide (NO), whereas the sustained relaxation involves both NO and some other factor(s).
Saito
R
R
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Japan.
Handa
K
K
Tanaka
S
S
Fukumitsu
A
A
Honda
K
K
Takano
Y
Y
Kamiya
H
H
D000818:Animals; D015237:Dinoprost / Q000494:pharmacology; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology*; D009126:Muscle Relaxation; D019335:Nitroarginine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D019335:Nitroarginine; D015237:Dinoprost