[Baroreceptor reflexes after exposure to the hypotensive action of prazosin blocking postsynaptic alpha 1-adrenergic receptors].

: The effect of prazosin, a selective blocker of post-synaptic alpha 1-adrenergic receptors, on baroceptor regulation was studied in experiments on narcotized rabbits. Following the intravenous administration of prazosin (5, 10 and 50 micrograms/kg) the blood pressure decreased, depending on the drug dosage. Transmission of the vasomotor activity to the vascular musculature was disrupted only partially. The pressor and depressor responses to changes in the output value of the baroreflex remained intact. The reaction of cardiac rhythm slowing in response to an increased pressure in the aorta disappeared. The sensitivity of the baroceptors was considerably elevated. In addition to the effector structures, prazosin influenced many other components of the system of the blood circulation reflex regulation.