Attenuating effects of prior oestradiol benzoate priming on 5-HT-mediated lordosis behavior in rats are dose-dependent.

The present study was designed to investigate the role of the 5-HT7 receptors in lordosis and compare the lordotic responses with 5-HT1A agent under the influence of different steroid-priming regimens in ovariectomized, non-receptive and receptive rats. 8-OH DPAT, a 5-HT1A agonist and 5-CT, a 5-HT7 agonist inhibited the lordosis differently in non-receptive and receptive rats, however, the response was attenuated in a dose-dependent manner following 5-CT treatment in the first two tests. Treatment with 5-HT1A antagonist, WAY 100 135 caused a protective effect which was evident in the second test only. Priming with 25 microg OB attenuated in the first test in non-receptive rats whereas the same dose repeated a similar pattern in receptive rats. The attenuation of LQ was evident in rats treated with 5-HT7 antagonist, SB 269970-A. This finding shows that WAY 100 135, a 5-HT1A antagonist has potency to attenuate inhibitory influence of 8-OH DPAT by enhancing lordosis behavior acutely in female rats with a low estrous state. Treatment with 5-CT and SB 269970-A as 5-HT7, agonist and antagonist, respectively, have mimicked 5-HT-mediated lordotic response as moderate affinity towards 5-HT1A receptors has been reported. This offers a comparable effect on lordosis as a result of the two 5-HT agents used.