Expression of mineralocorticoid receptors mRNA in the brain, heart and kidney of Sprague Dawley rats with renovascular hypertension

A large body of evidence indicates that mineralocorticoids play significant role in regulation of cardiovascular functions and in pathogenesis of several forms of hypertension by means of multiple effects exerted in the brain, heart and kidney. However, little is known about regulation of expression of mineralocorticoid receptors mRNA in the hypertensive states. The purpose of the present study was to determine whether expression of mineralocorticoid receptors mRNA is altered in the brain as well as in the left ventricle of the heart and in the kidney in the rats with the Goldblatt 2K,1C renovascular hypertension. Competitive PCR method was used for relative quantitative analysis of mineralocorticoid receptors mRNA in the brain, heart and kidney samples harvested from 12 to 14 weeks old, male Sprague Dawley rats subjected either to constriction of the left renal artery (n = 8) or to the sham surgery (n = 9). The 2K,1C rats manifested significantly higher systolic blood pressure (P < 0.005) and significantly reduced weight of the left kidney (P < 0.001) in comparison to the sham-operated rats. In both groups, mineralocorticoid receptors mRNA was well expressed in the preoptic, diencephalic, mesencephalopontine, medullary and cerebellar regions of the brain, and in the heart, renal cortex and the renal medulla. Significant differences were found between expression of MR mRNA in different brain regions. In the 2K,1C rats, expression of mineralocorticoid receptors mRNA was significantly lower than in the sham-operated rats in the mesencephalopontine (P < 0.02) and medullary (P < 0.005) regions of the brain as well as in the heart (P < 0.030) and the renal medulla of the kidney (P < 0.001). No significant differences were detected in the other brain regions and in the renal cortex. The results provide evidence that mineralocorticoid receptors mRNA expression is significantly diminished in the brain stem, the heart and the renal medulla of rats with the 2K,1C renovascular hypertension.