Adaptation of the human carotid baroreceptor-cardiac reflex.

1. Four intensities of neck suction were applied for 5 sec in healthy young men to determine the time course of decay of carotid baroreflex sinus node inhibition. 2. Peak responses occurred at about 1-25 sec after the onset of baroreceptor stimulation and were proportional to the intensity of stimulation. 3. Responses declined steadily during the remaining period of stimulation; the rate of decay of sinus node inhibition was decribed well by a power function and was proportional to the intensity of baroreceptor stimulation. 4. beta-adrenergic blockade did not alter the rate of decay of abroreflex sinus node inhibition. 5. These results suggests that adaptation of the integrated baroreceptor-cardiac reflex occurs in man and follows the same time course as adaptation of individual baroreceptor units an experimental animals.