ABSTRACT
The effect of ICV injection of baclofen [GABA[B] agonist and CGP35348 [GABA[B] antagonist] on serum concentration of estradiol and progesterone in proestrous phase. Experimental study. Twenty female Sperague Dawley rats weighning 200-250g were used. For ICV injection a director canula was inserted into the lateral ventricle by stereotaxic surgery. Each injection was performed 30 min before blood sampling. Blood samples were collected 9, 11 and 13h after initiation of proestrous. Estradiol and progesterone levels were determined using RIA method. Data were analyzed by One Way ANOVA, repeated meature ANOVA and post-hoc Tucky test. The level of significance was at P<0.05. Present data demonstrated that baclofen at doses of 4.27 and 8.54 ng/rat significantly increased and decreased serum concentration of estradiol, respectively [p<0.05]. baclofen at the same doses significantly increased serum concentration of progesterone in 11 a.m and 1 p.m [P<0.05]. CGP35348 in both doses had no significant effect on serum concentration of estradiol, while in 5 g/rat significantly increased the serum concentration of progesterone [P<0.05]. The results indicate that GABA[B] receptor may has an important role in the control of estradiol and progesterone secretion in the proestrous phase of female rats