[Effects of enflurane on respiratory neurons of the pre-Bötzinger complex in medullary slices of neonatal rats].

Volatile anesthetics depress respiration and neuronal activity of the central nervous system. Recently, a limited region of the ventral medulla (pre-Bötzinger complex; PBC) has been assumed to be the core of respiratory rhythm generation. The transverse brainstem slice preparation containing PBC was used in neonatal rats to investigate the effects of enflurane on respiratory neurons. Enflurane significantly depressed the frequency and the amplitude of spontaneous respiratory bursts in a concentration-dependent manner. In the presence of the GABAA antagonist bicuculline (20 microM) and the glycine antagonist strychnine (1 microM), the effectiveness of enflurane in reducing the activity of PBC diminished by 50%. These results suggest that the enflurane-induced decrement of spontaneous activity of respiratory neurons is partly caused by an increase in synaptic inhibition.