Functional Changes in Aqp4 Gene Expression in the Rat Hypothalamus under Different Drinking Regimens and Arterial Hypertension

Aquaporin-4 (AQP4) is the main water channel in the centralnervous system. AQP4 is highly expressed in brain structures, suggestingits crucial role in water transport in norm and in pathology. Here,we studied the effect of a change in the drinking regimen (waterdeprivation, hyperhydration) and inherited arterial hypertensionon the expression of the AQP4 water channel gene in the hypothalamus,a regulatory brain center of visceral functions. The expressionlevel of the Aqp4 gene in hyperhydrated animalswas found to be more than 1.5 times lower than in water-deprivedanimals, which may reflect the need to prevent cytotoxic edema duringincreased fluid intake. Rats with inherited stress-induced arterialhypertension are characterized by an increased level of the Aqp4 gene in the hypothalamus, suggestingthe involvement of this channel in processes associated with theregulation of brain water balance and the prevention of vasogeniccerebral edema in arterial hypertension. Thus, the presence of theAQP4 water channel in the brain, associated with the protectionof brain cells, is functionally determined by the state of the body,as evidenced by bidirectional changes in Aqp4 expressionduring hyperhydration and arterial hypertension.