[Effect of various biologically active substances on the tonus of smooth muscle cells of the arteries of the diencephalon].

The direct action of biologically active substances on the smooth muscle cells tone was studied in isolated segments of the cow diencephalic arteries. The serotonin, histamine, vasopressin, potassium ions were found to induce a dose-dependent increase of the smooth muscles tone. Weak responses to oxytocin and noradrenaline were revealed.