MOTOR INNERVATION OF SMOOTH-MUSCLE OF RAT SEMINAL-VESICLE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 201  (2) , 285-297
Abstract
Frequency-related isovolumetric contractions of the rat seminal vesicle elicited with transmural electrical stimulation were blocked by tetrodotoxin but unaffected by hexamethonium. Postganglionic motor innervation of the rat seminal vesicle is purely excitatory and contains an adrenergic and cholinergic component which are excited simultaneously during transmural stimulation. Contractions elicited by adrenergic nerve stimulation were mediated by norepinephrine acting via .alpha.-adrenoceptors, i.e., responses of untreated vesicles to transmural stimulation and to exogenous norepinephrine were antagonized by phentolamine and potentiated by cocaine, and treatment of animals with reserpine or 6-hydroxydopamine produced a marked depletion of tissue norepinephrine concentration and reduced responses to transmural stimulation to a level which resembled that of untreated organs in the presence of phentolamine. The residual responses of vesicles from pretreated rats were not modified by phentolamine or cocaine, and responses to tyramine in untreated organs were antagonized by phentolamine but not by cocaine and were observed in organs from reserpine-pretreated rats only after repletion with exogenous norepinephrine. Responses elicited by cholinergic nerve stimulation were mediated by acetylcholine through muscarinic receptors, i.e., responses of untreated vesicles to transmural stimulation and to exogenous acetylcholine were antagonized by atropine, and the residual responses to transmural stimulation of vesicles from animals pretreated with reserpine or 6-hydroxydopamine were nearly abolished by atropine. Physostigmine potentiated and prolonged responses of organs from untreated and reserpine-pretreated animals to transmural stimulation; these effects of physostigmine were abolished by atropine.

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