HALOTHANE INCREASES THE OPEN PROBABILITY OF GLYCINE-ACTIVATED CHANNELCURRENT IN RAT CENTRAL NEURONS

Glycine-activated single-channel currents in rat central neurones were recorded using the outside-out mode of the patch-clamp technique. The unitary conductance of the current was 21 pS. The current evoked by 1 0 mu M glycine had a mean burst duration of 47.8 (2.6) ms and open pro bability of 0.09 (0.016). Halothane (1 mM) increased the open probabil ity to 0.19 (0.03) without changing either unitary conductance or burs t duration. These results suggest that halothane increased the open pr obability via an increase in the affinity of the receptor for the agon ist. Potentiation of the glycine response may reduce excitability of p ostsynaptic neurones and may contribute to general anaesthesia produce d by volatile agents.