Baroreceptors and the long-term control of blood pressure

The current consensus is that arterial baroreceptors are vitally important in the short term (seconds to minutes) control of mean arterial pressure (MAP) but are unimportant in determining the long-term level of MAP. The latter statement is based primarily on two observations: first, that baroreceptors rapidly reset to the prevailing level of MAP and second, that total baroreceptor denervation has no lasting effect on the average daily MAP, although the variability of MAP is increased dramatically. However, recent studies in intact experimental animals have produced results that suggest baroreceptor resetting may not be as rapid or complete as previously thought. Furthermore, reconsideration of the responses to baroreceptor denervation suggest that the condition may accurately represent responses to short-term baroreceptor unloading but not long-term unloading. Results obtained using a new model of chronic baroreceptor unloading indicate that the condition results in a sustained increase in MAP. These results strongly suggest that the role of baroreceptors in the long term control of MAP needs to be revisited.