Plasticity of subfornical organ astrocyte structure and supraoptic nucleus hormone expression following extreme dehydration in the desert rodent Gerbillus tarabuli.

The central nervous system plays a pivotal role in the regulation of water and electrolyte balance, largely via the circumventricular organs (CVOs) and the hypothalamo-neurohypophysial system. Gerbillus tarabuli, a desert-dwelling rodent capable of surviving in arid environments, remains poorly characterized with respect to the neuroendocrine mechanisms underlying its hydromineral adaptation In the present study, we examined the effects of long-term dehydration (4 weeks) in G. tarabuli. We focused on glial fibrillary acidic protein (GFAP) expression in the subfornical organ (SFO), as well as vasopressin (VP) and oxytocin (OT) expression in magnocellular neurons (MCNs) of the supraoptic nucleus (SON) using immunohistochemistry. Physiological parameters, including body mass, plasma osmolality, sodium concentration, hematocrit, and glycemia, were also assessed. In dehydrated gerbils, the observed changes in body mass, plasma osmolality, natremia, and glycemia were not significantly different from those of euhydrated gerbils. In contrast, hematocrit was significantly increased (5.53%), corresponding to a 15.97% reduction in plasma volume. Long-term dehydration induced a marked increase in GFAP immunoreactivity within the SFO, concomitant with a significant increase in VP and OT immunoreactivity and enlargement of magnocellular soma size in the SON. Additionally, the SON of G. tarabuli showed a mediolateral extension in the dorsolateral region of the optic chiasm (OC). Together, these findings identify G. tarabuli as a valuable model for investigating the neuroendocrine mechanisms underlying hydromineral homeostasis and the central adaptations supporting survival in arid environments.