SEXUAL DIMORPHISM IN THE RESPONSE OF THE GAMMA AMINOBUTYRIC-ACID-ERGIC SYSTEM TO ESTROGEN ADMINISTRATION

Administration of estradiol benzoate to gonadectomized female rats results in up-regulation of CNS .gamma.-aminobutyric acid (GABA) receptors. The increase of [3H]muscimol binding activity is observed in six of the seven brain areas examined. The same treatment, performed in castrated male or androgenized female rats, induced an increase of [3H]muscimol binding only in the striatum. Evidence is provided suggesting that the dimorphic sensitivity of GABA receptor is not correlated with the difference in spontaneous motor activity reported between male and female rats.