Presence of serotonin in the rat vas deferens: its influence on contractile responses.
Serotonin has been detected in the rat vas deferens. Increase in the serotonin concentration by exposure of the rat vas deferens to L-tryptophan occurs in vitro. p-chlorophenylalanine partly blocks the increase in serotonin concentration induced by tryptophan in vitro but not in vivo. Chronic sympathetic denervation induces an increase in 5-HT concentration. Responses of the vas deferens to transmural stimulation are depressed by pretreatment of rats with p-chlorophenylalanine, and the depression is reversed by incubation in vitro with 5-hydroxytryptophan or serotonin. Serotonin can enhance the response to transmural stimulation at low concentrations but has no effect at higher concentrations. Physostigmine-induced enhancement of the response to stimulation is depressed only by higher concentrations of serotonin. The results raise the question whether endogenous serotonin can act as a modulator of neurotransmission in the rat vas deferens.
Fuenmayor
L
L
Department of Physiological Sciences, Pharmacology, Vargas Medical School, Central University of Venezuela, Caracas, Venezuela.
Gomez
J
J
Campos
H A
HA
Romero
E
E
D000818:Animals; D003714:Denervation / Q000009:adverse effects; D004558:Electric Stimulation; D010134:Fenclonine / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000096:biosynthesis*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013997:Time Factors; D014364:Tryptophan / Q000378:metabolism / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*
D012702:Serotonin Antagonists; D012701:Serotonin; D014364:Tryptophan; D010134:Fenclonine