Influence of the estrous cycle on some non reproductive behaviors and on brain mechanisms in the female rat

Abstract

El rol de las hormonas sexuales sobre el comportamiento reproductivo ha sido extensamente documentado. La fluctuación periódica de hormonas sexuales en hembras de numerosas especies ha sido relacionada con cambios comportamentales no sexuales tales como humor, ansie dad, agresión y respuesta a estrés. El sustrato bioló-gico-neural de estos cambios se basa en los cambios que estas hormonas inducen en el Sistema Nervioso Central. Este trabajo resume algunos cambios que afectan a receptores y neurotrasmisores de los sistemas GABAérgico, serotoninér-gico, dopaminérgico y péptido liberador de prolactina del SNC de la rata. La rata hembra posee un ciclo sexual de 4 días de duración, denominado ciclo estrual. La presente revisión se informa en tres secciones. (1) Se presenta una breve descripción de la variación de tres hormonas sexuales principales con acción directa sobre el SNC: estrógenos (E2), progesterona (P4) y prolactina (PRL). Se han descripto propiedades ansiolíticas para P4 y anti-estrés para PRL; para E2, la bibliografía es controvertida, describiéndose acciones excitatorias y anti-estrés. (2) Se informan algunos cambios cerebrales y comportamentales que tienen lugar en cada estadio del ciclo estrual. Las fluctuaciones hormonales se consideran bá-sicas para la interpretación de tales cambios. (3) Se mencionan algunos hallazgos acerca de la influencia hormonal cíclica sobre los sistemas de neurotransmisión del SNC y sobre un nuevo pép-tido propuesto como mediador de la respuesta a INTERDISCIPLINARIA, 2012, 29, 1, 63-77 63 INFLUENCE OF THE ESTROUS ABSTRACTSex hormone fluctuations in females are involv ed in some behavioral states such as mood, anxiety, aggression and stress response, due to functional changes in the central nervous system (CNS) activity induced by the cyclic sex hormone fluctuation. This review includes three sections.1.-A description of the three major hormone fluctuations in the estrous cycle: estrogens (E2), progesterone (P4) and prolactine (PRL). E2 achieves the maximum circulation levels during P. E2 is mainly excitatory and has been considered to have an antidepressive action. The highest plasma levels of P4 and its metabolite allopregnenolone (ALLO) occur in P. Ovulation takes place in the night of P, and the resulting corpora lutea produces a secondary increase in P4 (and ALLO) on D. The P4 peak level occurring in D1 and in the evening of P was shown to exert benzodiazepine-like effects, including sedation. It has been proposed that ALLO, rather than P4 is the one acting on GABA systems. Circulating levels of ALLO parallel those of P4 across the estrous cycle and is known to have anxiolytic properties.PRL is produced mainly in the adeno hy pophysis, though synthesis in other sites of the brain also occurs. Its regulation is mostly inhibitory and is exerted by dopamine (DA) released in the hypothalamus. A surge in PRL secretion occurs during P. PRL would be a modulator of the HPA-axis, and is considered as a stress hormone.2.-Some behavioral and neural changes occur at each stage ...

Effects of the Female Estrous Cycle on the Sexual Behaviors and Ultrasonic Vocalizations of Male C57BL/6 and Autistic BTBR T+ tf/J Mice

“…The estrous cycle affects many behavioral and psychiatric states, including mood, anxiety, stress responses, sexual receptivity, learning, and memory [ 4 5 6 7 8 9 ]. In particular, sexual receptivity is highest at a stage in which copulation is crucial for successful reproduction [ 10 ].…”

“Rapid actions of the neurosteroid allopregnanolone on ovarian and hypothalamic steroidogenesis: Central and peripheral modulation”

“…ALLO is one of the most studied neurosteroids at the CNS level, and its concentration varies throughout the oestrous cycle, pregnancy and under stress situations . ALLO can act via the mPR, 5HT 3 receptor, pregnane X receptor, and via the GABA A receptor, the most studied signalling pathway .…”