Dose-dependent Increases in the Renal Sympathetic Nerve Activity during Rapid Increase in Isoflurane Concentration in Intact, Lower Airway-deafferented, and Baroreceptor-deafferented Rabbits

摘要: Background : The inhalation of high concentrations isoflurane has been reported to increase the heart rate and concentration serum catecholamines. Although precise mechanisms for sympathetic activation have yet be clearly elucidated, they are considered possibly originate from stimulation airway sensory afferents, baroreceptor reflex, or direct central nervous system. To determine how these three contribute augmentation, effects lower deafferentation on isoflurane-induced changes in renal nerve activity (RSNA) tracheally intubated rabbits were examined. Methods Twenty given basal anesthesia. After tracheotomy during mechanical ventilation, rate, mean arterial pressure, RSNA response random exposures 1%, 2%, 3%, 4% animals assigned one groups ; 1, intact group (n = 6) 2, baroreceptor-deafferented 9), which sinoaortic plus vagal nerves cut 3, airway-deafferented 5), underwent a bilateral vagotomy. exposure was 10 min 1 5 2 3. At least h allowed recovery interval between isoflurane. Results caused dose-dependent increases all groups. began at min, reaching maximum 4 (2.8- 3.8-fold 3% isoflurane, respectively) 3 4.5-fold respectively), but it reached peak (1.7- 2.4-fold after initiation inhalation, association with early slight followed by decreases pressure only gradual similar however, those significantly attenuated compared 1. Conclusions an intact, baroreceptor-deafferented, rabbits. extent greater than Therefore, is suggested that may efferent via system reflex reflecting reduction blood pressure. vagally innervated not