Differential effects of the aging process on the morphology of the hypothalamic ventromedial nucleus of male and female rats.

摘要

We investigated the effects of aging on the neuroanatomical sex dimorphisms of the rat hypothalamic ventromedial nucleus (VMN). Stereological methods were used to estimate the volume of the VMN and the total number and size of its neurons, including their dendritic trees, in males and females aged 6 and 24 months. No cell loss was detected in aged rats. However, in aged females, the volume of the VMN and the somatic size of its neurons were increased, whereas in aged males the dendritic spine density was augmented. Due to these gender-specific effects, the male-female differences observed in the morphology of the VMN in adult rats were annulled in aging. Our findings support the notion that some structural sex dimorphisms in the brain are not stable throughout the life span.