Effect of GABA-acting drugs diazepam and sodium valproate on thermoregulation in rats

Gamma-aminobutyric acid (GABA) is involved in the mechanism of action of many drugs affecting different functions in the central nervous system. The present study has investigated the effect of diazepam, a positive allosteric GABA_A receptor modulator, and sodium valproate, a GABA transaminase inhibitor, on thermoregulation in rats. The experiments were designed into two main parts: (1) in vivo experiments on body temperature of conscious rats; (2) in vitro experiments on temperature sensitivity (temperature coefficient, TC) of rat PO/AH neurons in slice preparations. Central (i.c.v.) or systemic (i.p.) administration of diazepam, as well as sodium valproate produced dose-dependent hypothermia in rats. Both GABAergic drugs diazepam and sodium valproate increased temperature sensitivity (TC) in warm-sensitive rat PO/AH neurons. These results are in agreement with the neuronal model of temperature regulation and confirm the involvement of GABAergic mechanisms in thermoregulation.