Cooperation of ATP and norepinephrine in inducing contractile responses in guinea pig vas deferens.
Stimulation of the hypogastric nerve to the guinea pig vas deferens induced biphasic contraction consisting of a rapid transient phase (mediated by ATP) and a delayed tonic phase (mediated by norepinephrine, NE), whereas stimulations in the presence of selective antagonists caused each contractile phase separately. Stimulation in the absence of antagonist induced a larger rapid transient contraction than that induced by stimulation in the presence of alpha 1-antagonist. Results obtained in separate or simultaneous additions of exogenous ATP and NE showed synergism in the rapid transient contraction. These findings indicate that NE assisted ATP in inducing the hypogastric nerve-mediated contractile response in guinea pig vas deferens, but not vice versa.
Kishi
I
I
Department of Veterinary Pharmacology, College of Agriculture, University of Osaka Prefecture, Japan.
Hata
F
F
Takeuchi
T
T
Ishii
T
T
Yagasaki
O
O
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D004558:Electric Stimulation; D006168:Guinea Pigs; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*; D014649:Vas Deferens / Q000187:drug effects* / Q000294:innervation
D000255:Adenosine Triphosphate; D009638:Norepinephrine