National Institutes of Health - NIH, sponsor, University of Liège, sponsor, Fonds Léon Fredericq, sponsor, Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS, sponsor, Giga-Neurosciences, research center
المصدر:
Changes in preoptic estradiol concentrations during male sexual behavior. Frontiers in Neuroscience.Lausanne, SwitzerlandFrontiers Research Foundation. (2017).
Besides its long-term control by steroids, male sexual behavior is also modulated by membrane-initiated effects of neuroestrogens in the short-term (within minutes). These effects are thought to depend on short-term variations in the local production of estrogens, through rapid fluctuations of the enzymatic activity of brain aromatase, the enzyme that synthesizes estradiol (E2) from testosterone. Studies in male Japanese quail have shown that a sexual interaction with a female leads to a decrease in the activity of brain aromatase within minutes. These effects occur mainly within the medial preoptic nucleus (POM), a sexually dimorphic structure of the preoptic area that plays a key role in the activation of male sexual behavior and contains the highest aromatase activity (AA) in the brain. However recent studies showed that AA does not always reflect local E2 concentration. For example, while an acute stress decreases AA in the POM, E2 concentration increases in the same conditions. Here we used in vivo microdialysis to quantify changes in E2 concentration in the male POM during sexual interactions with a female. A series of experiments conducted to validate the in vivo dialysis and RIA methods showed that (1) E2 concentration in the dialysate change linearly with the concentration of a bath containing known amounts of E2 in which the probe was placed, (2) an increase in preoptic E2 concentration is observed after retrodialysis of testosterone and (3) preoptic E2 levels also increase after a peripheral injection of E2. Together these results suggest that in vivo dialysis is a suitable method to assay E2 in the range of brain concentrations suspected to be present in physiological conditions. With this approach, we showed during two independent experiments that E2 concentrations increase in the POM during sexual interactions with a female. Birds that had their cannula placed outside the POM did not show any increase in E2 levels. The E2 increase in the POM could serve to maintain motivation during the entire sexual encounter. The decrease of AA observed ex vivo after copulation would then reflect a compensatory mechanism to restore baseline pre-copulatory conditions.
نوع الوثيقة:
conferenceObject
اللغة:
English
العلاقة:
12th congress of the Belgian Society for Neurosciences (22 mai 2017)
