METABOLISM OF THE MAJOR PROTEIN KINASE C SUBSTRATE NAP-22 IN HIPPOCAMPUS AND PARIETAL CORTEX OF SPONTANEOUSLY-HYPERTENSIVE RATS: THE IMPACT OF DIETARY SALT LOAD

Objective. To assess the changes in NAP-22 messenger ribonucleic acid (mRNA) expression level as well as NAP-22 protein content in hippocampus and in parietal cortex of spontaneously-hypertensive rats after longterm dietary salt load (nutritional factor of the arterial hypertension, HTN). design and methods. We examined SHR and WKY male rats before and after 1 % NaCl consumption instead of drinking water. NAP-22 mRNA level was estimated using real time PCR, and the content of NAP-22 protein and its isoforms was evaluated by electerophoresis with subsequent immunoblotting. Results. In spontaneously-hypertensive rats, NAP-22 mRNA expression in parietal cortex significantly decreased after the salt load, the decrease was more profound in parietal cortex than in hippocampus and even more expressed in the normotensive control. After the salt load, NAP-22 protein level in parietal cortex decreased more in SHR rats than in the normotensive rats. conclusions. Although both salt load and dietary calcium deficiency induce similar changes in blood pressure, intracellular mechanisms of developing HTN are different. Intracellular signaling cascades involved in the salt load model need further investigation.

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