Discriminative stimulus properties of ethanol in the rat: Effects of neurosteroids and picrotoxin

Tetrahydrodeoxycorticosterone (5 beta-THDOC; 1.3-12.0 mg/kg), a neurosteroid enhancing the GABA(A) receptor-associated chloride conductance, produced predominantly ethanol-appropriate responding (> 80%) in rats trained to discriminate 1.0 g/kg ethanol from saline. However, neither picrotoxin (0.25-1.5 mg/kg), nor dehydroepiandrosterone sulfate (0.01-100.0 mg/kg), a neurosteroid acting as a GABA, receptor antagonist, attenuated the stimulus effects of ethanol. These results indicate that: (1) at least certain neurosteroids may produce subjective states similar to these induced by ethanol; (2) blockade of the GABA(A) receptor-associated channel does not eliminate the ethanol interoceptive cue in rats. (C) 1997 Elsevier Science B.V.