mTOR Expression in Neurons of the Rat Tuberal Hypothalamus in Aging

The expression of the mTOR (mammalian target of rapamycin) protein kinase and RICTOR (rapamycin-insensitive companion of mammalian target of rapamycin) protein was studied immunohistochemically in neurons of the tuberal region of the rat hypothalamus in male rats aged 3, 6, 12, and 24 months. We have shown for the first time the presence of mTOR-immunopositive (ip) neurons in the arcuate (ARN), dorsomedial (DMN), and ventromedial (VMN) hypothalamic nuclei, as well as RICTOR-ip neurons in the ARN and VMN in rats of different ages. In the ARN of aging rats, the percentage of mTOR-ip neurons increases, while the proportion of mTOR-ip neurons colocalizing mTOR and RICTOR decreases. In the VMN and DMN, a highest percentage of mTOR-ip neurons was observed in 6-month-old rats. A highest percentage of RICTOR-ip neurons was found in the VMN of 6-month-old rats. Thus, aging is accompanied by changes in mTOR expression in neurons of the hypothalamic tuberal nuclei.

Automated summary

This study investigated the expression of mTOR and RICTOR proteins in neurons of the tuberal region of rat hypothalamus at different ages. The results showed changes in the proportion of mTOR and RICTOR immunopositive neurons in the hypothalamic nuclei with aging. The highest percentage of mTOR and RICTOR immunopositive neurons was observed in the ventromedial nucleus of 6-month-old rats.