CA2- PARTICIPATION ON RAT SEXUAL HYPOTHALAMIC DIFFERENTIATION( CALMODULIN SYSTEM )

Modifications of male rat hypothalamic sexual differentiation after ne onatal administration of drugs that participate on the Ca2+/calmodulin system (haloperidol, trifluoperazine, penfluridol, pimozide, and vera pamil) were studied. Pups treated 72 h after birth were behaviorally t ested on day 120 of extrauterine life. Five tests for homotypical beha vior were conducted. Afterwards animals were castrated and tested twic e for heterotypical (female) behavior under replacement hormonal thera py. Fifty percent (80% in the case of pimozide) of all treated males s howed lordotic behavior compared with none of the controls. Haloperido l (39%, lordosis quotient) and pimozide (40%, lordosis quotient) were more active than the others. Results obtained with verapamil were not statistically different from the controls. Pimozide was the most activ e agent influencing the appetitive masculine behavior (mount latency, intromission latency, and postejaculatory interval). Verapamil was mor e efficient than the rest of the drugs on the consummatory behavior (m ount latency, intromission frequency, interintromission interval, and ejaculatory latency). Our results support the participation of the Ca2 +/calmodulin system in hypothalamic sexual differentiation and in the differential modulation of the masculine and feminine behavioral patte rns.