Halothane enhances tonic neuronal inhibition by elevating intracellular calcium - PubMed (original) (raw)

Halothane enhances tonic neuronal inhibition by elevating intracellular calcium

I Mody et al. Brain Res. 1991.

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Abstract

Whether the major action of anesthetics is to depress the central nervous system (CNS) by reducing excitation or enhancing inhibition remains unknown. Using whole cell patch-clamp recording in hippocampal slices, halothane and pentobarbital were found to prolong the decay time constant (TAU(D)) of GABAA-mediated spontaneous inhibitory postsynaptic currents (sIPSCs). Intracellular administration of the Ca2+ chelator BAPTA or the Ca2+ release inhibitor dantrolene significantly (ANOVA, P less than 0.005) reduced halothane's effect; in contrast, the pentobarbital effect was unchanged. Halothane induced depression of population spike amplitude was blocked by the GABAA antagonist bicuculline. Together, these findings suggest that a major depressant effect of halothane involves enhancement of GABAA-mediated inhibition through release of intraneuronally stored Ca2+.

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