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Caldwell HK, Albers HE: The effects of serotonin agonists on the hypothalamic regulation of sexual receptivity in Syrian hamsters. Horm Behav. 2002 Aug;42(1):78-84.
One brain region that has been implicated in the regulation of lordosis is the medial preoptic-anterior hypothalamic continuum (MPOA-AH). Previous studies have suggested that this zone may be part of the circuit mediating the effects of serotonin (5-HT) on sexual receptivity. In the present experiments, we investigated the role of 5-HT (1a/7) and 5-HT (2) receptor subtypes in the MPOA-AH in the control of lordosis. In two experiments, either 5-HT (1a/7) or 5-HT (2) agonists were injected unilaterally into the MPOA-AH of ovariectomized, hormonally primed female hamsters. In the first experiment, microinjections of the 5-HT (1a/7) agonist 8-hydroxy-2,9-(di-n-propylamino) tetralin resulted in an attenuation of the lordosis posture by causing a decrease in the mean lordosis duration and an increase in the number of lordosis episodes over the entire testing period. In the second experiment, microinjections of the 5-HT (2b/2c) agonist m-chlorophenylpiperazine did not result in any changes in sexual receptivity. However, microinjections of the 5-HT (2) agonist (2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl facilitated lordosis by increasing the mean lordosis duration and decreasing the number of lordosis episodes in the first 5 min of the testing period. These data indicate that serotonin may act in the MPOA-AH via 5-HT (1a/7) receptors to attenuate and 5-HT (2) receptors to facilitate sexual receptivity. |
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