Effect of delequamine (RS15385) on female sexual behaviour in the rat

The role of adrenoceptors in the central nervous system in male and female rat sexual behavior

“…Delequamine and phenoxybenzamine, another α 2 -adrenoceptor antagonist and nonselective adrenoceptor antagonist respectively, have also shown to be ineffective on lordosis quotient and paracopulatory behavior in ovariectomized female rats primed with both estradiol and progesterone (Davis and Kohl, 1977;Gonzalez et al, 1996). However, the same study showed that delequamine has a facilitatory effect on lordosis quotient in nonreceptive females primed with only low levels of estradiol, although no effect was found on paracopulatory behaviors (Gonzalez et al, 1996).…”

“…Another study, on the other hand, showed that VMN injections of clonidine had no effect on lordosis behavior in estradiol-primed females (Kow et al, 1992). Local VMN injections of the α 2 -adrenoceptor antagonist delequamine actually increased the lordosis quotient in ovariectomized females primed with only estradiol (Gonzalez et al, 1996), which was explained by its effect on presynaptic α 2 -adrenoceptors and thereby enhancing the release of noradrenaline. In females primed with both estradiol and progesterone, it was found that the nonselective α 2 -adrenoceptor antagonist idazoxan had no effect on both lordosis behavior and paracopulatory behaviors (Etgen, 1990), while the selective α 2 -adrenoceptor antagonist yohimbine decreased lordosis responses without affecting the number of paracopulatory behaviors (Etgen, 1990).…”

“…Interestingly, α 2 -adrenoceptor antagonists have no intrinsic effects on lordosis when locally injected into the MPOA (delequamine (Gonzalez et al, 1996); indazoxan (Etgen, 1990); yohimbine (Etgen, 1990)). This indicates that under normal basal circumstances α 2 -adrenoceptors in the MPOA do not play a crucial role in sexual behavior, but with elevated levels of α 2 -adrenoceptors become more important.…”

Female Reproductive Behavior

“…Systematic administration of an α2adrenoceptor agonist, for instance, does not have an effect on lordosis in female rats (Davis and Kohl, 1977). Similar lack of results were found with the administration of non-selective and selective α2-adrenoceptor antagonists: no effects were found on sexual incentive motivation, paracopulatory behavior and lordosis (Snoeren, 2015, Gonzalez et al, 1996, Davis and Kohl, 1977, Ventura-Aquino and Fernandez-Guasti, 2013. This suggests that, systemically, α2adrenoceptors are not involved in the regulation of female sexual behavior.…”

“…This inhibitory effect is most likely regulated via α2-adrenoceptors and not α1-or β-adrenoceptors in the POA. It should be mentioned, though, that α2-adrenoceptor antagonists by itself do not affect lordosis when locally injected into the POA (Gonzalez et al, 1996, Etgen, 1990). This indicates that under normal basal circumstances α2-adrenoceptors in the POA do not play a crucial role in sexual behavior, but with elevated levels of NA, α2-adrenoceptors become more important.…”