RESUMEN
Studies have shown that changes in ovarian hormone concentrations promote natural fluctuations in the density of dendritic spines of hippocampal neurons in female Sprague-Dawley rats, without changes in dendritic length, throughout the estrous cycle. However, it is still unknown whether these fluctuations are present in other rat strains. Due to our interest in Wistar rats, the objective of the present study was to determine if there is natural dendritic remodeling in the female Wistar rat throughout the estrous cycle. This study analyzed the dendritic arborization of pyramidal neurons CA1 and CA3 of the dorsal hippocampus in each phase of the estrous cycle. We used the Golgi-Cox staining method and Sholl analysis to evaluate the dendritic length and density of dendritic spines. Our results showed that the dendritic length of the basilar and apical trees of CA1 neurons was longer in the metestrus phase. In CA3 neurons, only the apical dendritic trees showed longer dendritic length during metestrus. There was no variation in the density of dendritic spines in relation to any of the phases of the estrous cycle. Taken together, these results indicated that pyramidal neurons of the CA1 and CA3 regions of the dorsal hippocampus in the Wistar rat exhibited changes in dendritic length in the metestrus phase of the estrous cycle. Together, these data are important when considering the use of these organisms in behavioral studies.
Asunto(s)
Región CA1 Hipocampal/citología , Región CA3 Hipocampal/citología , Espinas Dendríticas/fisiología , Metestro/fisiología , Neuronas/citología , Análisis de Varianza , Animales , Espinas Dendríticas/ultraestructura , Femenino , Neuronas/ultraestructura , Ratas , Ratas Wistar , Tinción con Nitrato de PlataRESUMEN
In previous studies, the anxiolytic-like effects of Montanoa tomentosa and Montanoa frutescens were reported in male rats, but the potential anxiolytic-like effects of Montanoa plants during the different phases of the ovarian cycle in rats remain to be explored. The anxiolytic-like effects of the aqueous crude extracts of M. frutescens (25 and 50 mg/kg) and M. grandiflora (25 and 50 mg/kg) in the elevated plus maze were investigated in Wistar rats during the estrous cycle and compared with 2 mg/kg diazepam as a reference anxiolytic drug. To investigate any motor effect (i.e., hyperactivity, no changes, or hypoactivity) associated with the treatments, the rats were evaluated in the open field test. The M. frutescens (25 and 50 mg/kg) and M. grandiflora (50 mg/kg) extracts exerted anxiolytic-like effects during the metestrus-diestrus phase, similar to diazepam, without disrupting spontaneous motor activity. No significant effects of the extracts were detected in either behavioral test during the proestrus-estrus phase, whereas diazepam produced motor hypoactivity in the open field test. These results indicate that the M. frutescens and M. grandiflora extracts possess anxiolytic-like effects that depend on the ovarian cycle phase, supporting the Mexican ancient medicinal use of these plants to ameliorate anxiety disorders.
Asunto(s)
Ansiolíticos/farmacología , Ansiedad/tratamiento farmacológico , Diestro/fisiología , Metestro/fisiología , Montanoa/química , Extractos Vegetales/farmacología , Animales , Ansiolíticos/química , Ansiolíticos/uso terapéutico , Conducta Animal/efectos de los fármacos , Femenino , Aprendizaje por Laberinto/efectos de los fármacos , Extractos Vegetales/química , Extractos Vegetales/uso terapéutico , Ratas , Ratas WistarRESUMEN
O presente experimento compara a nível de microscopia de luz a morfologia do epitélio uterino de ratas congenitamente atímicas (rnu/rnu) com a de suas "littermtes" eutímicas (rnu/ +), da linhagen Rowett, nas fases de proestro e de metaestro do ciclo estral. Pudemos observar que a morfologia do epitélio uterino das ratas homozigotas (rnu/rnu) foi semelhante à das heterozigotas (rnu/ +), em ambas as fases estudadas e compatível com a morfologia uterina descrita na literatura referente a ratas comuns. No metaestro verificamos epitélio do tipo cilíndrico simples e áreas deste epitélio em desarranjo com algumas das células apresentando vacuolizaçäo citoplasmática e núcleo picnótico. No proestro, o epitélio cilíndrico simples apresentou-se constituído por células contendo núcleo alongado deslocado para a porçäo basal
Asunto(s)
Animales , Femenino , Ratas , Masculino , Metestro/fisiología , Proestro/fisiología , Útero/citología , Epitelio , Ratas DesnudasRESUMEN
We explored the oxytocin-prostaglandin interactions during the rat estrous cycle. The experiments were done with uterine preparations isolated from rats in different stages of the sex cycle incubated 'in vitro' with oxytocin (O) (50 mU/ml). We found that the effect of O on prostaglandin (PG) synthesis was associated to the sex hormones, and varied during the estrous cycle. Indeed, during the estrogenic influence (i.e. at proestrus and estrus) O diminished the synthesis of PGE2 and with the highest estradiol concentration (i.e. during estrus) the hormone also augmented the synthesis of PGF2 alpha. During metestrus, no changes in PG synthesis after treatment were found. Likewise, during diestrus, when progesterone levels fall, O enhanced PGF2 alpha uterine synthesis. In this study an inhibitory action of O on the uterine production of 6-keto-PGF1 alpha at proestrus was also seen. The present results indicate that when estrogen concentration increases (during estrus) 6-keto-PGF1 alpha synthesis also increases. In summary, we have observed that sex hormones exert a modulating action on the influences of O on uterine PGs synthesis.
Asunto(s)
Estro/fisiología , Oxitocina/farmacología , Prostaglandinas/biosíntesis , Útero/metabolismo , 6-Cetoprostaglandina F1 alfa/biosíntesis , Animales , Ácido Araquidónico/metabolismo , Diestro/fisiología , Dinoprost/biosíntesis , Dinoprostona/biosíntesis , Femenino , Metestro/fisiología , Proestro/fisiología , Ratas , Ratas Wistar , Útero/efectos de los fármacosRESUMEN
We have previously demonstrated the presence of tissue kallikrein and its mRNA in rat uterus, and an increase of the immunoreactive enzyme on Day 7 of gestation, which suggests a hormonal regulation and a role in implantation. This study pursued the sequential variations during the cycle and early pregnancy. During the estrous cycle, immunoreactive uterine kallikrein levels showed a recurrent pattern, with the highest value on proestrus (12.9 +/- 1.5 ng/uterus or 0.49 +/- 0.03 ng/mg protein), and the lowest on metestrus (4.1 ng +/- 0.5 ng or 0.30 +/- 0.03 ng/mg protein); p < 0.05. During gestation, values on Day 1 (6.1 +/- 0.4 ng/uterus or 0.30 +/- 0.01 ng/mg protein) and Day 3 (4.9 +/- 0.3 ng or 0.35 +/- 0.01 ng/mg protein) were similar to levels during estrus and diestrus; a progressive rise, observed from Day 5 (8.2 +/- 1.1 ng or 0.43 +/- 0.02 ng/mg protein), attained the highest value on Day 7 (15.8 +/- 1.7 ng or 0.78 +/- 0.05 ng/mg protein); p < 0.05. The variations observed during the cycle and early gestation coincide with those described for ovarian steroids and uterine vasoactive changes, suggest the hormonal regulation of uterine kallikrein levels, and support its role in implantation.
Asunto(s)
Estro/fisiología , Calicreínas/metabolismo , Preñez/metabolismo , Útero/metabolismo , Animales , Diestro/fisiología , Femenino , Metestro/fisiología , Embarazo , Proestro/fisiología , Ratas , Ratas Sprague-DawleyRESUMEN
En el presente estudio se observa la ultraestructura del estroma endometrial de ratas congenitamente atímicas (rnu/rnu), homozigotas para el gen nude recesivo y de sus camadas eutímicas (+/rnu), heterozigotas para el mismo gen, ambas de la línea Rowet, con el propósito de detectar posibles alteraciones en las ratas rnu/rnu. Estudios morfológicos del aparato reproductor de éstas, usando microscopio de luz, no muestran diferencias de las ratas +/rnu. Estudios ultraestructurales referentes a este asunto no fueron encontrados en la literatura consultada. La ultraestructura del estroma endometrial de rnu/rnu y +/rnu mostraron fibroblastos con una GER más dilatada en el proestro que el metaestro y una menor frecuencia de eosinófilos y macrófagos en las ratas rnu/rnu que en las +/rnu en proestro. La frecuencia de monocitos fue mas alta en el proestro mientras que la de los neutrófilos fue mas baja en el proestro y metaestro, en ambos grupos de ratas. Los resultados ultraestructurales sugieren que la menor frecuencia de eosinófilos y macrófagos encontrados en la ratas rnu/rnu en fase de proestro pueden estar relacionados con atmia congénita y/o alteraciones en los niveles de hormonas esteroidales encontradas en esas ratas