Antineophobic effect of the neuroactive steroid 3alpha-hydroxy-5beta-pregnan-20-one in male rats

The neuroactive steroid 3alpha-hydroxy-5beta-pregnan-20-one (pregnanolone) and benzodiazepine receptor (BZR) agonists share sedative, anxiolytic, and anticonvulsant properties. Recent evidence suggests that like BZR agonists, pregnanolone may also modulate feeding responses. The present experiments examined the behavioral mechanisms responsible for any hyperphagic effect of pregnanolone. The effect of pregnanolone (1-10 mg/kg i.p.) on the intake and microstructure of licking for two sucrose solutions (1 and 3%) in well familiarized nondeprived male rats under either light or dark conditions was examined. Pregnanolone had no effect on either intake or the duration or number of bouts of licking in these experiments, although in all cases the intrabout lick rate was significantly reduced at the highest dose. Pregnanolone (1-10 mg/kg) also failed to increase intake of a sweet wet mash in familiarized nondeprived male rats. However, in a food choice test where both novel and familiar food items were available, pregnanolone (1-3 mg/kg) significantly increased the time spent eating the novel food. These results suggest that unlike BZR agonists, which enhance feeding responses directly, pregnanolone may facilitate feeding secondarily via an attenuation of anxiety.