[Effect of stimulation of the hypothalamus on the rhythmogenic activity of the smooth musculature of the ureters and systemic arterial pressure]

The influence of low- and high-frequency stimulation of anterior, tuberal and posterior hypothalamic areas on the spontaneous rhythmogenesis in the ureter smooth muscles and on arterial blood pressure, was studied in anesthetized cats. High-frequency stimulation of all hypothalamic areas induced pressor responses with activating effects on motor activity of the ureter. The changes in the ureter rhythmic activity were synchronous with those of systemic arterial blood pressure. The low-frequency stimulation induced both pressor and depressor responses in different proportion. The depressor responses were not accompanied by any changes of the ureter rhythmic activity. Possible mechanisms of reversal of vasomotor responses in stimulation of hypothalamus, organization of sympathico-activating and sympathoinhibitory mechanisms and hypothalamic regulation of rhythmogenic function of the ureter, are discussed.