[An analysis of the baroreflex influences on the systemic hemodynamics in head-down tilt]

In acute experiments on cats, the effect of carotid sinus' baroreceptors on systemic hemodynamics, was studied in antiorthostasis. Head-down tilt of the animals 15-45 degrees increased the arterial pressure and cardiac output whereas the heart rate and total peripheral resistance were decreased. The tests with decreasing the arterial pressure yielded analogous results. Exclusion of baroreceptors of the carotid sinus did not affect the initial shifts in the group with increasing arterial pressure. Whereas in the group with decreasing arterial pressure the same procedure reversed the reaction.