New approach of the cardio-vascular depressive mechanism during lateral hypothalamic stimulation.

Paraventricular nucleus stimulation acts directly on the alpha- and beta-adrenoreceptors in heart and arterioles, eliciting arterial hypotension and cardiac chronotropism and inotropism decrease. Efferent pathways follow sympathetic nervous fibres through the medulla and the thoraco-lumbar ganglionic chain. The role of the alpha- and beta-adrenoreceptors in these depressive reactions is discussed.