Contrôle baroréflexe de l'activité nerveuse sympathique chez le rat

Abstract

In the rat, a spontaneous index of the sensitivity of the baroreflex control of sympathetic nerve activity (SNA) has been developed, validated and applied. It is based on the calculation of the transfer function gain between arterial pressure (AP) and SNA, at heart rate frequency. Cardiac pacing, in anesthetized rats, showed that this gain is not influenced by heart rate fluctuations. By measuring renal SNA in conscious rats with either intact or partially denervated baroreceptors, it was found that this index is positively correlated with the baroreflex sensitivity measured by the pharmacological method. The functional relevance of this index was confirmed by the existence of an inverse relationship with AP variability. In intact rats, acute exposure to air jet stress sensitized the baroreflex control of renal SNA, when . This index, calculated over 1-min consecutive periods in conscious rats revealed that the sensitivity of the baroreflex control of renal SNA fluctuates spontaneously over time. The computation of this index using both renal and lumbar SNAs, simultaneously recorded in conscious rats, pointed to a homogenous baroreflex regulation of regional SNAsLYON1-BU.Sciences (692662101) / SudocSudocFranceF