[The effect of adrenotropic substances on contraction of the rat ductus deferens induced by the action of adrenaline and transmural stimulation].

In the rat isolated ductus deferens, effects of isadrine, propranolol and phentolamine on contractions following exogenous noradrenaline and transmural stimulation, were studied. Low concentrations of isadrine diminished the responses to these factors. The inhibiting effect of a mimetic was blocked by propranolol which indicates presence of beta-adrenoreceptors in the rat ductus deferens; low concentrations of phentolamine blocked the exogenous adrenaline effect while the response to transmural stimulation increased. As the data show, the adrenoreceptors' sensitivity to noradrenaline is decreased by phentolamine 5-10(-8) M by 2.5 times while the mediator concentration increases by 3.3 times in the receptors vicinity. Alpha-adrenoreceptors are concluded to differ from beta those in that the former do participate in regulation of noradrenaline release in response to neural impulses.