Visceral afferents and the fastigial nucleus in vascular and plasma renin adjustments to head-up tilting.

摘要: A two min orthostatic stress of 30 degrees head-up tilting in alpha-chloralose anesthetized and paralyzed cats results compensatory changes cardiovascular parameters (systemic blood pressure, renal perfusion pressure) renin release. The dynamics the response leads to shifts systemic arterial pressure characterized by 3 phases. initial phase, a fall is followed rapid phase with period that does not exceed 50 s. near steady-state adjustment vascular resistance represents third has longer time constant adequately accounted for both cardiopulmonary baroreflex mechanisms. Indeed, fixing carotid sinus vagotomized cat at high or low levels alters only magnitude obtained tilt early compensation second phase. By contrast, bilateral lesions fastigial nucleus cerebellum abates tilting. Renin secretion significantly increased (greater than 2 1/2) this increase was abolished vagotomy. cat, resulted modest rise secretion. Following such as upwards trend abated. Three neural components (cerebellar pressor, baroreflex) appear necessary integrated tilt. adjustments comprise well long-term humoral responses.