Effects of acetaldehyde on contractile response to nerve stimulation in guinea-pig vas deferens.
Twitch contractions of the isolated guinea-pig vas deferens induced by sympathetic nerve stimulation were augmented by acetaldehyde (0.1-10 mM). With high concentrations (5-10 mM), acetaldehyde produced a biphasic response consisting of an initial brief depression and a subsequent potentiation of the contraction. The late effect was associated with repetitive contractions that were not prevented by tetrodotoxin. A low concentration of phentolamine (27 microM) increased and a high concentration (1.3 mM) suppressed the potentiating action of acetaldehyde. Acetaldehyde did not induce contractions in surgically sympathectomized vasa or vasa pretreated with reserpine. Acetaldehyde caused a dose-dependent increase in noradrenaline release into the bathing fluid. The study shows that acetaldehyde has a dual effect on sympathetic neuroeffector transmission, and that an increase in noradrenaline secretion appears to contribute to the late facilitatory effect in the isolated vas deferens.
Takeda
R
R
Department of Pharmacology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Momose
Y
Y
Haji
A
A
D000079:Acetaldehyde / Q000494:pharmacology*; D000818:Animals; D004558:Electric Stimulation; D004566:Electrodes; D006168:Guinea Pigs; D006584:Hexamethonium Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009121:Muscle Denervation; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D010646:Phentolamine / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology; D013562:Sympathectomy; D013564:Sympathetic Nervous System / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects / Q000378:metabolism / Q000502:physiology
D006584:Hexamethonium Compounds; D013779:Tetrodotoxin; D012110:Reserpine; D000079:Acetaldehyde; D009638:Norepinephrine; D010646:Phentolamine