Alterations of Neurohumoral Response to Acute Stress in Spontaneously Hypertensive Rats Subjected to Long-Term Isolation

Hypertension is a serious disease characterized by a sustained or recurrent increase in blood pressure, which can lead to various complications. Here, we studied the effect of genetically determined arterial hypertension in rats on their adaptation to long-term isolation and subsequent response to acute restraint stress. Male SHR rats with spontaneous hypertension were maintained in individual cages for 14 weeks. The serum levels of corticosterone, glucose, and pro- and anti-inflammatory cytokines and salivary α-amylase activity were studied, and the expression of genes associated with the regulation of steroidogenesis in the adrenal glands was evaluated. There were no significant changes in the parameters of the hypothalamic–pituitary–adrenocortical and sympatho-adrenal systems after isolation. Nevertheless, the preliminary isolation significantly affected the response to moderate restraint stress, including the expression of the regulatory genes Fkbp5 and Star in the adrenal glands and the content of proinflammatory cytokines IL-1β and IL-6 in the blood, although the changes in these indices were relatively subtle. This may reflect the predisposition of animals in isolation to develop quite specific stress-related changes.