CA2+ CALMODULIN SYSTEM - PARTICIPATION IN THE PROGESTERONE-INDUCED FACILITATION OF LORDOSIS BEHAVIOR IN THE OVARIECTOMIZED ESTROGEN-PRIMED RAT/

We studied the effect some drugs that participate in the Ca2+/calmodul in system have on the progesterone (P) facilitation of lordosis behavi or in ovariectomized estradiol (E(2)) primed rats. We injected rats 44 h after E(2) priming with 2 mg P together with various dosages of one of the following compounds: pentobarbital, trifluoperazine (TPZ), pro methazine (PMZ), Chlorpromarine (CPZ), haloperidol (HAL), pimozide (PI M), and verapamil (VER). Then 4 h after treatment, animals were tested for sexual behavior, expressed as the lordosis quotient (LQ). All dru gs at 4 mg/kg or higher inhibited lordosis, but only HAL, PIM, and VER were active at 1 mg/kg. The maximum level of activity was shown by PI M, although al the dose of 8 mg/kg no statistical differences were fou nd between this compound and TPZ or HAL. Pentobarbital (25 mg/kg) show ed no significant difference from saline-treated controls. The activit y of the tested drugs on the facilitation of sexual behavior appears t o be related to their efficiency as inhibitors of calmodulin (CaM)-dep endent phosphodiesterase and as ligands for the Ca2+-CaM complex.