A. Fernandez-Guasti

Bio: A. Fernandez-Guasti is an academic researcher from CINVESTAV. The author has contributed to research in topics: Inhibitory postsynaptic potential & Postsynaptic potential. The author has an hindex of 1, co-authored 1 publications receiving 41 citations.

Role of presynaptic serotonergic receptors on the mechanism of action of 5-HT1A and 5-HT1B agonists on masculine sexual behaviour: physiological and pharmacological implications.

Abstract: In order to establish whether the 5-HT1A or the 5HT1B agonists, 8-OH-DPAT or TFMPP, produce their facilitatory or inhibitory actions on masculine sexual behaviour via a mechanism involving: (a) the serotonin synthesis or release; (b) the stimulation of presynaptic receptors, or (c) the stimulation of somatodendritic receptors, three series of experiments were performed. The administration of the serotonin synthesis inhibitor, p-chlorophenylalanine (p-CPA, 300mg/kg×3 days), facilitated sexual behaviour but does not interfere neither with the inhibitory nor with the facilitatory effects of TFMPP (0.5mg/kg) or 8-OH-DPAT (0.5 mg/kg), respectively. The icv or the intraraphe administration of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), slightly stimulated masculine sexual behaviour and produced a decrease in serotonin and its metabolite levels. In lesioned animals TFMPP (0.5 mg/kg) resulted in an inhibitory effect reflected as a prolongation of the ejaculation latency. The inhibitory effect of this drug on mounting behaviour was not observed in 5,7-DHT treated rats. In lesioned animals 8-OH-DPAT (0.5 mg/kg) produced the same facilitatory effect. Present data indicate that serotonergic postsynaptic receptors mediate both the inhibitory and the facilitatory actions of TFMPP or 8-OH-DPAT in copulation. All data further support the idea that endogenous serotonin acts via the stimulation of 5-HT1B receptors to induce its inhibitory effects on masculine sexual behaviour.

Male Sexual Behavior

Abstract: Male sexual behavior comprises a complex pattern of genital and somatomotor responses. Hormones act via receptors in brain, spinal, and peripheral sites to bias sensory inputs and motor outputs to favor sexual responsiveness. Copulation includes mounts, intromissions, and ejaculations, followed by sexual quiescence. After 6–12 ejaculations, male rats become sexually satiated. Neural controls include chemosensory inputs via the main and accessory olfactory systems to the medial amygdala, which transmits information directly and indirectly to the medial preoptic area (mPOA), which integrates sensory and hormonal information and elicits genital reflexes and copulatory patterns and contributes to sexual motivation. Genital sensory input arrives via the central tegmental field/dorsolateral tegmentum (including the subparafasicular nucleus) directly or indirectly into the mPOA. Output from the mPOA is via the paraventricular nucleus and midbrain and brainstem sites. The mesocorticolimbic dopamine pathway contributes motivational fervor, and neural programs for erection and ejaculation reside in the lumbosacral spinal cord. Dopamine facilitates male sexual behavior, whereas serotonin (5HT) is largely inhibitory, although stimulation of 5-HT1A receptors facilitates ejaculation. Norepinephrine has both stimulatory and inhibitory effects on copulation, via α1- and α2-adrenoceptors, respectively. Endogenous opioids play a complex modulatory role in all aspects of copulation. The brain areas that regulate male sexual behavior also influence other social behaviors.