Central adrenergic neurons and the control of blood pressure

Abstract

Publisher Summary This chapter elaborates the central adrenergic neurons, and the control of blood pressure. It is observed that central adrenergic neurons are involved in the cardiovascular control stems mainly from two types of observations. Some hypotensive drugs, in particular α-methyldopa, and Clonidine reduce peripheral sympathetic tone, and lower blood pressure predominantly by an interaction with central adrenergic structures. Intravenous administration of Clonidine to cats is followed by a decrease in spontaneous sympathetic nerve activity, blood pressure and heart rate. Hypothalamic stimulation after Clonidine causes a similar discharge pattern in the peripheral sympathetic nerves as does combined stimulation of the sinus nerves, and the posterior hypothalamus. This discharge pattern is not further modified by additional stimulation of the sinus nerves. It is found that Clonidine induced a state which closely resembles that of an activation of the depressor baroreceptor reflex. In view of the well-known property of Clonidine to stimulate α-adrenoceptors, the possibility was considered that the central part of the baroreceptor reflex arc is under the influence of adrenergic neurons.