Changes in neuronal contribution to contractile responses of vas deferens of young and adult guinea pigs.
The response characteristics of vas deferens to electrical hypogastric nerve stimulation at various frequencies was studied in guinea pigs of 2 to 15 weeks old. In 2-week-old guinea pigs the stimulation induced monophasic contraction, some of which remained after blocking alpha 1-adrenoceptor and desensitizing P2-purinoceptors with prazosin and alpha, beta-methylene ATP, respectively. In guinea pigs of 10 to 15 weeks old stimulation induced biphasic contraction, which was almost completely inhibited by both blockers. These results suggest that some unknown component other than ATP and norepinephrine is involved in the transmission at 2 weeks, and that its relative significance changes during development.
Nagao
T
T
Department of Veterinary Pharmacology, College of Agriculture, University of Osaka Prefecture, Sakai, Japan.
Fujita
A
A
Takeuchi
T
T
Hata
F
F
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D007001:Hypogastric Plexus / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009474:Neurons / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D014649:Vas Deferens / Q000502:physiology*
D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D011224:Prazosin