ABSTRACT
Objective:To explore the role of reactive oxygen species(ROS,i.e,H_2O_2 and O_2-) in regulation of respiratory rhythm in the medial area of nucleus retrofacialis(mNRF).Methods: Medullary slices of neonatal SD rats,including hypoglossal nerve(Ⅻn) and mNRF,were made according to Suzue's method.Simultaneous recording of the Ⅻn respiratory rhythmic activity(RRA) with suction electrode and the respiratory neuronal discharge were performed with whole cell patch in the mNRF on the brainstem slice in vitro.The effect of t-butyl hydroperoxide(tBHP) and ?-lipoic acid(?-LA) on the respiratory pacemaker neurons and respiratory rhythm in the mNRF were observed.Results: tBHP significantly decreased respiratory cycle(RC) and increased respiratory amplitude;?-LA significantly increased RC and decreased its amplitude.Meanwhile,?-LA significantly prolonged the action potential of the respiratory cadmium-insensitive pacemaker neurons and reduced its amplitude,but it had no significant effect on the cadmium-sensitive respiratory pacemaker neurons.Voltage steps and ramps showed that ?-LA inhibited both the transient and persistent sodium current of cadmium-insensitive pacemaker neurons.Conclusion: ROS has an excitatory effect on the respiratory rhythm and the cadmium-insensitive respiratory pacemaker neurons through modulating sodium current.