Reversal of helpless behavior in rats by putative 5-HT1A agonists.

This study is designed to measure effects of serotonin 1A (5-HT1A) agonists on escape deficits produced by inescapable shock in rats--a model of learned helplessness. Rats were first exposed to 60 inescapable shocks (15-sec duration, 0.8 mA, every 1 min +/- 15 sec), and 48 hr later, they were subjected to daily 15-min shuttle-box sessions (30 trials/day) on 3 consecutive days. Twice daily intraperitoneal injection of buspirone (total daily dose of 0.5 and 1 mg/kg), gepirone (0.06 and 0.125 mg/kg), 8-OH dipropylamino-tetralin (8-OH-DPAT) (0.03, 0.06, 0.125, and 0.25 mg/kg), and ipsapirone (TVXQ 7821) (0.03 and 0.06 mg/kg) eliminated escape failures. This indicates that an antidepressant-like effect--reversal of helpless behavior--can be obtained with drugs assumed to stimulate serotonin 1A receptors.