Altered serotonin innervation in the rat epileptic brain.

Studies in animal models of epilepsy revealed compromised serotonin (5-HT) transmission between the raphe nuclei and the brain limbic system. The goal of the present study was to evaluate the effects of epilepsy on the structural integrity of the dorsal (DR) and median (MnR) raphe nuclei and on the morphology of serotonergic fiber terminals in the dentate gyrus (DG), infralimbic cortex (IL) and medial septum (MS). The study was performed in adult Wistar rats using the kainate (9.5 mg/kg) status epilepticus (SE) model. Four months post-SE, the brainstem sections of the animals were immunostained for 5-HT, whereas the forebrain sections were immunostained for serotonin transporter (SERT). Stereological analysis revealed that epileptic rats, as compared to controls, had approximately 30% less 5-HT-stained cells in the interfascicular part of the DR, but twice as many 5-HT-stained cells in the MnR. Another finding was the reorganization of the 5-HT fiber network in all target areas analyzed, as indicated by the rightward shift of the density-size distribution histograms of SERT-stained fiber varicosities. Nonlinear regression analysis of these histograms revealed that SERT-stained varicosities were represented by two subpopulations characterized by distinct cross-sectional areas. The areal density of the small-sized varicosities was decreased in the DG (hilus and molecular layer), IL cortex (layers II/III) and MS, while that of the larger-sized varicosities was increased. The present results support the hypothesis that chronic epilepsy can trigger profound structural reorganization of the ascending serotonergic pathways in the rat brain.

Influência da ooforectomia na variação ponderal em ratas jovens e adultas / Influence of oophorectomy on the weight variance in young and adult female rats

Para avaliar a influência do tempo de ooforectomia na variação ponderal, foram utilizadas 60 ratas, divididas em dois grupos (30 em cada grupo): Grupo A - jovens; e Grupo B - adultas. Os animais de cada grupo foram subdivididos em três subgrupos: Subgrupo 1 - controle (n= 6); Subgrupo 2 - laparotomia (n= 6); Subgrupo 3 (n= 18) - ooforectomia total bilateral. Os animais foram pesados semanalmente durante 13 semanas e os resultados foram avaliados pelo teste t de Student, com significância para p<0,05. As ratas ooforectomizadas tiveram ganho ponderal maior do que as demais, sendo a diferença significativa a partir da 11ª semana no Grupo A e 9ª semana no Grupo B, persistindo até o fim do experimento. No presente trabalho, a ooforectomia bilateral em ratas relacionou-se com maior ganho ponderal, independente da idade dos animais.

[Influence of oophorectomy on weight variance in young and adult female rats]. / Influência da ooforectomia na variação ponderal em ratas jovens e adultas.

To assess the effects of oophorectomy on body weight, 60 adult female rats were divided into two groups (30 in each group): Group A -- young rats; Group B -- adult rats. The animals of each group were divided into three subgroups: Subgroup 1 (n= 6) -- control; Subgroup 2 (n= 6) -- laparotomy; Subgroup 3 (n= 18) -- bilateral oophorectomy. The weight of the animals was weekly assessed during 13 weeks and the results were compared by Student t test, with significance for p<0.05. The oophorectomized rats presented higher weight gain than those of the other groups. The difference was significant after eleven weeks, in Group A, and nine weeks, in Group B, until the end of the experiment. In the present work, bilateral oophorectomy in rats was related to higher body weight, independent on the age of the animals.