RESUMO
Social relations are built and maintained from the interaction among individuals. The oxytocin (OT), vasopressin (VP), estrogen, dopamine, and their receptors are involved in the modulation of sexual behavior in females. This study aimed to analyze the impact of OT gene knockout (OTKO) on sexual behavior and the gene expression of oxytocin (OTR), estrogen alpha (ERα), estrogen beta (ERß), vasopressin (V1aR), and dopamine (D2R) receptors in the olfactory bulb (OB), prefrontal cortex (PFC), hippocampus (HPC), and hypothalamus (HPT), as well as in the synthesis of VP in the HPT of female mice. Wild-type (WT) littermates were used for comparisons. The CDNAs were synthesized by polymerase chain reaction and the gene expression was calculated with the 2-ΔΔCt formula. Our results showed that the absence of OT caused an increase in the frequency and duration of non-receptive postures and a decrease in receptive postures in the OTKO. OTKO females showed a significant decrease in the gene expression of OTR in the HPC, V1aR in the HPT, and ERα and ERß in the PFC. There was no significant difference in the gene expression of D2R of OTKO. However, OTKO showed an increased gene expression of V1aR in the HPC. There is no significant difference in VP mRNA synthesis in the HPT between OTKO and WT. Our findings demonstrate that the absence of OT leads to significant changes in the expression of the studied genes (OTR, ERα, ERß, V1aR), and these changes may contribute to the decreased sexual behavior observed in OTKO females.
Assuntos
Encéfalo/metabolismo , Técnicas de Inativação de Genes , Sistemas Neurossecretores/metabolismo , Ocitocina/genética , Comportamento Sexual , Animais , Feminino , Regulação da Expressão Gênica , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ocitocina/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Dopaminérgicos/genética , Receptores Dopaminérgicos/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Receptores de Vasopressinas/metabolismo , Vasopressinas/genética , Vasopressinas/metabolismoRESUMO
The posterodorsal medial amygdala (MePD) is a sexually dimorphic area in the social behavior neural network, with high concentration of oxytocin (OT) receptors. Wild type (WT) and OT knockout (OTKO) females were studied in proestrus, and Golgi-impregnated spines in the MePD were classified. Results show that the OTKO group has increased density of thin, mushroom, and stubby/wide spines when compared to the WT (p<0.01 in all cases). These data indicate that OT is an important synaptic modulator in the MePD, a finding that is likely involved with the display of the female sexual behavior.
Assuntos
Tonsila do Cerebelo/citologia , Tonsila do Cerebelo/fisiologia , Espinhas Dendríticas/fisiologia , Ocitocina/fisiologia , Receptores de Ocitocina/fisiologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proestro , Receptores de Ocitocina/genéticaRESUMO
Central oxytocin (OT) and arginine-vasopressin (AVP) have been shown to play an important role in sexual behavior and neuroendocrine secretion in rodents. The results of exogenous OT administration on sexual behaviors in male and female mice are controversial. This study aimed to analyze the role of OT in sexual behavior, the number of oocytes and the density of dendritic spines in the posterodorsal medial amygdala (MePD) of female mice with selective deletion of the OT gene (OTKO). Female C57BL/6 mice were genotyped and divided into control (WT) and OTKO groups (n=11 each). All experiments were performed in the proestrus phase. Compared to WT data, our results showed that the OTKO group had a significant increase in the latency for the display of lordosis behavior (490.8 ± 113.8 and 841.9 ± 53.9, respectively) and a decrease in both the frequency (6.3 ± 2.4 and 0.5 ± 0.4) and duration (49.3 ± 19.9 and 7.2 ± 7.1) of lordosis and a reduction in the number of oocytes (12.2 ± 0.8 and 9.9 ± 0.6). However, the OTKO group showed a higher density of proximal dendritic spines in the MePD compared to the WT group (2.4 ± 0.1 and 1.9 ± 0.1 spines/dendritic µm, respectively). No significant difference was observed in the plasma levels of AVP between the groups (OTKO: 617.1 ± 96.0 and WT: 583.3 ± 112.0 pg/mL). Our data suggest that OT plays a crucial role in the sexual behavior display, number of released oocytes and density of dendritic spines in the MePD of female mice. The AVP plasma concentration was not affected in the OTKO animals.