ABSTRACT

Arterial baroreceptors in the carotid sinuses and aortic arch are stimulated by vascular stretch during increases in arterial pressure. Resetting of the baroreflex can be defined as a change in the relation between arterial pressure and peripheral vascular resistance and heart rate, or between pressure and sympathetic and parasympathetic nerve activities. The relationship between arterial pressure and baroreceptor activity may be altered by acute or chronic changes in the prevailing level of arterial pressure or by pressure-independent mechanisms. Peripheral baroreceptor resetting enables the baroreceptors to continue to function effectively in the buffering of acute fluctuations in arterial pressure. For example, baroreceptor activity increases initially as arterial pressure rises but then declines gradually as the elevated pressure is maintained. Resetting of the baroreflex during increased arterial pressure has been attributed to peripheral baroreceptor resetting, i.e., a decreased responsiveness of baroreceptors to a rise in pressure.