GABAERGIC DRUGS AND SEXUAL-BEHAVIOR IN THE RABBIT - EVIDENCE FOR SPECIES-SPECIFIC EFFECTS

The effects of gamma-amino butyric acid (GABA)-ergic drugs on male rab bit sexual behaviour have been evaluated, The GABAA agonist 4,5,6,7-te trahydroxixazolo-5,4c-pyridin-3-ol (THIP), the GABA(B) agonist R-baclo fen and the GABA antagonists picrotoxin and bicuculline were used. Inj ection of THIP, 20 mg/kg, s.c. produced a complete suppression of sexu al behaviour and R-baclofen, 2.5 mg/kg, s.c. a significant inhibition. Intraperitoneal injections produced effects at higher doses than did s.c, injections. The inhibition produced by R-baclofen was associated with strong motor effects as shown by the water escape test. It is pro bable, therefore, that the reduced sexual behaviour observed after tre atment with this drug is a consequence of sedative or muscle relaxant effects. By contrast, the dose of THIP that inhibited sexual behaviour had no effect on the water escape test. These results show that the G ABA(A) agonist inhibits sexual behaviour in the male rabbit independen t of effects on the motor system. The GABA antagonists had marginal or no effects on sexual behaviour. When these data are compared to previ ous results in the rat, substantial differences are seen. As there are differences between the effects on rat and rabbit sexual behaviour by other types of drugs, it appears that drug action on sexual behaviour cannot be generalized from one species to another.