[The effect of an alpha-adrenoblocker and a calcium-channel blocker on the spontaneous tonus of an isolated blood-perfused artery].

The existence of spontaneous myogenic tone was shown on an experimental model of an isolated artery perfused "ex vivo" with blood from the rat donor. Administration of the alpha-adrenoblockers prasosine and yohimbine into the perfusion medium in the bath was followed by a 60% decrease in the myogenic tone. The nonspecific blocker of calcium channels CaCl2 decreased the rest of the tone by 15%. The remaining 20-25% of the initial myogenic tone was inhibited by sodium nitroprusside. Urethane (300 mg/kg) or nembutal (20 mg/kg) injected intravenously into the rat donor may lead to an increase or a decrease in the myogenic tone, respectively. The conclusion is made that the advantage of the experimental model proposed lies in the existence of the spontaneous myogenic tone of an arterial vessel depending on humoral catecholamines and some other vasoconstrictor factors.