[Effects of sevoflurane anesthesia and baroreceptor function on renal sympathetic nerve activity in rats]

Effects of sevoflurane at various anesthetic levels on renal sympathetic nerve activity (RSNA), blood pressure and heart rate were studied in rats. Changes of these parameters produced reflexly by noxious cutaneous stimulation and effects of baroreceptor on them were also studied. Under the resting condition by increasing inspired sevoflurane concentration decreased blood pressure and heart rate dose-dependently, whereas, RSNA was unchanged. But, without the baroreceptor function, RSNA decreased and the change paralleled with changes of blood pressure and heart rate. When noxious stimulation was applied on a hindpaw by pinching, blood pressure, heart rate and RSNA all increased at sevoflurane 2.1%. The responses of these parameters were attenuated at 3.1% and almost disappeared at 4.2% of sevoflurane. However, without the baroreceptor function, RSNA increased even at 3.2 and 4.2% as at 2.1% of sevoflurane. It is suggested that under sevoflurane anesthesia, baroreceptor system has strong influences on RSNA even under sevoflurane 4.2% (2MAC).