Objective To investigate the effects of
propofol on the electric discharge of the
inspiratory neurons in the neonatal rat brainstem
slices and its possible mechanism. Methods Experiments were performed on in vitro neonatal rat (of either sex, 0 to 30 d old) brainstem slices perfused with modified Kreb's solution (MKS), and the rhythmical discharge activity of the in-spirotory neurons in the hypoglossal nerve was recorded by suction electrode. Thirty-six slices positive of respiratory-related rhythmic activity were randomly divided into 6 equal groups consisting of a control group (groupⅠ) with MKS
perfusion, 4 propofol groups (groups ⅡtoⅤ) with propofol treatment delivered via continuous MKS perfusion for 3 min at the doses of 5, 20, 50, 100 μmol/L respectively, and a bicuculline-propofol group (group Ⅵ) with the continuous perfusion of bicuculline (20 μmol/L) and propofol (20 μmol/L). The discharge time course of inspiratory, expiratory, peak inspiratory discharge and the frequency of respiration were recorded before and 1, 3, 5, 10, 15, 30 min after propofol or bicuculline-propofol perfusion. Re鄄sults In control group, no significant changes took place in all Hreparameters in the whole course of the experiment. In groupsⅡto Ⅳ, the discharge time was significantly reduced after propofol perfusion and at 5 min, and the discharge was arrested in 4 out of the 6 slices in group Ⅴ, showing a concentration-dependent inhibition of the inpiratory discharge time by propofol. In contrast, the expiratory time course was prolonged and frequency of respiration decreased in the period of 3 to 30 min after propofol perfusion. Combined treatment of bicuculine and propofol produced no significant changes in the discharge time and expiratory time courses of the inspiratory neurons. Conclusion Propofol inhibits the discharge of inspiratory neurons in a con-centration-dependent manner and
GABA A receptor may play an important role in this process.
More abstracts about the Effect of propofol on the electric discharge of inspiratory neurons in the brainstem of neonatal rat