Hypothalamic control of baroreceptor reflexes.
Hypothalamic control of baroreceptor reflexes.
复制标题
下丘脑控制压力感受器反射。
DOI：
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发表时间：
1970
影响因子：
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通讯作者：
D. Snyder
中科院分区：
文献类型：
--
作者：
G. L. Gebber;D. Snyder
1969.-The elect of hypothalamic stimulation was studied on the cardiac and vascular efferent components of the baroreceptor reflexes. Bradycardia evoked by carotid sinus nerve stimulation or norepinephrine was blocked by hypothalamic stimulation in spinal cats. These data demonstrate the existence of a suprabulbar system which functions to inhibit vagal bradycardia induced by baroreceptor activation. In contrast, baroreceptor modulation of central sympathetic outflow was functionally important during hypothalamic stimulation. The depressor response produced by carotid sinus stretch was not reduced by hypothalamic stimulation in vagotomized cats. The pressor response evoked by hypothalamic stimulation was markedly enhanced during carotid occlusion or following section of the carotid sinus nerves, Also, peripheral sympathetic nerve discharges elicited by hypothalamic stimulation were reduced when arterial pressure was raised. It is concluded that tachycardia associated with the pressor response evoked by hypothalamic stimulation was the result not only of increased cardiac sympathetic nerve activity, but also of inhibition of baroreceptor-induced vagal activation. potential THE CARDIOVASCULAR RESPONSE evoked by electrical stimulation of selected areas of the posterior hypothalamus is characterized by an increase in arterial pressure and heart rate (4, 8, 9, 12, 18). I n many respects, such a response simulates that observed during muscular exercise (11, 12, 18). Bard (1) has questioned why the baroreceptor reflexes fail to curtail the increase in heart rate which is maintained in the presence of the hypertensive response evoked from the hypothalamus. Two possibilities have been considered in the present investigation. First, does the increase in cardiac sympathetic activity elicited by hypothalamic stimulation (8) override the maximal cardiac inhibitory effect of the baroreceptor reflexes? Alternatively, do suprabulbar pathways exist which function to inhibit the compensatory baroreceptor reflexes? That is, does hypothalamic activation " debuffer " the animal so as to allow for the lability of cardiovascular function associated with certain stressful situations? The data presented indicate that maintenance of high heart rate in the presence of the rise in blood pressure produced by stimulation of the hypothalamus is related to inhibition of baroreceptor-induced vagal bradycardia. MATERIALS AND METHODS Sixty-five cats were anesthetized by the intravenous injection of chloralose (40-55 mg/kg) or by the intraperitoneal administration of a mixture of sodium diallylbarbiturate (70 mgikg), urethan (280 mg/kg), and monoethylurea (280 mg/kg)+ A heating pad was used to maintain rectal temperature at 38 C. Eight experiments also were performed on artificially respired unanesthetized spinal cats. Transec-tion of the spinal cord at the …
