[Hypothalamic participation in regulating parasympathetic reflexes to the heart in unanesthetized cats]

Abstract

The influences of electrical stimulation of different hypothalamic areas on cardiac parasympathetic reflexes were studied in unanesthetized unrestrained cats. Cardiac reflexes were induced by imitation of venous input increase to the heart or by stimulation of cervical part of the vagus. The hypothalamus exerted two-way effects on cardiac reflexes: they were either increased or decreased during hypothalamic stimulation. This suggests that the hypothalamus renders facilitating as well as inhibitory influences on cardiac reflex bradycardia. The forebrain is supposed to participate in cardiac regulation by modulating cardiac reflexes both in unanesthetized cats and anesthetized ones.