Changes in preference for male faces during the menstrual cycle in a Spanish population / Cambios en la preferencia por rostros masculinos durante el ciclo menstrual en población española

A recent and controversial hypothesis suggests the presence of an oestrus phase in women as in other mammals. This implies that women at their optimal fertility point of the menstrual cycle exhibit behaviors focused to maximize the genetic quality of their offspring. Several studies support this hypothesis, finding that women in the fertile phase tend to prefer men with traits associated to phenotypic quality, such as greater facial masculinization and symmetry. We experimentally tested some of the observations supporting this hypothesis in a population of 810 young Spanish women. We analyzed whether the preference for masculinized male faces is affected by I) the phase of the menstrual cycle, II) having a stable partner and III) the use of birth control pills. We could not repro-duce the effect of the first two factors, but we found that women using hormonal contraceptives tend to prefer men with less masculine faces. These results indicate that some of the evidences supporting the oestrus hypothesis in humans must be reviewed, incorporating data from different socio-cultural and ethnic populations

Recientemente se ha postulado una controvertida hipótesis que propone la presencia de un periodo de estro en las mujeres, como ocurre en otros mamíferos. Ello implica que las mujeres en el óptimo de fertilidad del ciclo menstrual presenten comportamientos encaminados a maximizar la calidad genética de su descendencia. Diversas investigaciones sostienen esta hipótesis, al encontrar que las mujeres en la fase fértil prefieren hombres con rasgos que denotan mayor calidad fenotípica, como un mayor grado de masculinización o una mayor simetría. Nuestro objetivo ha sido testar experimentalmente en una población de 810 jóvenes españolas alguna de estas observaciones. Analizamos si, tal como se recoge en la bibliografía, la preferencia por rostros de hombres masculinizados se ve afectada por I) la etapa del ciclo menstrual, II) el tener pareja estable y III) el empleo anticonceptivos hormonales. No hemos podido reproducir el efecto de los dos primeros factores, pero sí encontramos que las mujeres que emplean anticonceptivos hormonales prefirieron rostros de hombre menos masculinos. Estos resultados no refutan la hipótesis del estro en humanos, pero nos indican que algunas de las pruebas que la sustentan han de ser reconsideradas, incorporando datos de poblaciones étnica y socioculturalmente diferentes

The antiepileptic effect of sodium valproate during different phases of the estrous cycle in PTZ-induced seizures in rats

Catamenial epilepsy is a form of epilepsy which is related to the menstrual cycle. Cyclic variation in the levels of ovarian hormones plays a pivotal role in its pathogenesis. Sodium valproate (VPA) is one of the oldest antiepileptic drugs (AEDs) which inhibits hepatic metabolizing enzymes. The aim of this study was to evaluate the antiepileptic effects of VPA during different phases of the estrous cycle in rats. 72 adult female Wistar rats in three groups (control, 75 and 100 mg/kg VPA), each with four subgroups (proestrous, estrous, metestrous and diestrous) were used (n = 6). Initially, puberty was assessed using vaginal smears and rats with two regular cycles were selected. VPA with doses 75 and 100 mg/kg was administered intraperitoneally (i.p) in the treatment groups followed by i.p. injection of 80 mg/kg pentylentetrazol (PTZ) in the treatment and control groups. After induction of seizure by PTZ, initiation time of myoclonic seizures (ITMS), initiation time of tonic-clonic seizures (ITTS), seizures duration (SD) and mortality rate (MR) were recorded for 30 min. Data were presented as mean±SD, one-way ANOVA followed by Tukey-Kramer multiple comparison post hoc test were used for analysis of data (P < 0.05). The results of this study showed that VPA significantly improved antiepileptic parameters including ITMS, ITTS, SD, and MR, in which they were significantly more prominent during the luteal phase than the follicular phase (P < 0.05). In addition, there was no significant difference neither between proestrous and estrous nor between metestrous and diestrous in each separately group of rats (P > 0.05) (AU)

Variaciones en la expresión cerebral del receptor opioide mu a lo largo del ciclo estral de la rata / Estrous cycle alters mu-opioid receptor immunostaining in the rat brain

Con el fin de observar las posibles alteraciones regionales de la expresión de receptores opioides mu en el cerebro de la rata que pudieran acontecer a lo largo del ciclo estral, se ha realizado un estudio inmunocitoquímico que ha demostrado la existencia de un incremento significativo del número de células nerviosas que expresan el receptor en la fase de proestro (a las 15.00 h), con respecto al estro, en el área preóptica medial del hipotálamo y la corteza piriforme. Estos resultados concuerdan con estudios previos en los que se ha demostrado que la expresión del receptor opioide mu en el prosencéfalo de la rata puede ser alterada por los esteroides gonadales (AU)