Aims: 

Hypertensive TGR (mREN-27) rats are characterized by hypertension and inverted blood pressure (BP) profile. The purpose of the study was to test the hypothesis that inverted BP profile correlates with clock genes expression in the brain areas responsible for BP regulation (paraventricular nucleus, area postrema).

Methods: 

Hypertensive TGR and normotensive Sprague-Dawley rats were synchronized to the lighting schedule 12L:12D. Brain nuclei were dissected by punching technique. Daily profile of clock genes expression was measured by real time PCR in the hypothalamic nuclei, brainstem and the circumventricular organ area postrema (AP). Plasma renin activity (PRA) was determined by radioimmunoassay.

Results: 

PRA was significantly higher in TGR in comparison with control animals. Expression of per2 was rhythmic in the most of analyzed nuclei and reached the maximum at beginning of the night. Expression of bmal1 was also expressed in rhythmic manner in the most nuclei and peaked at the beginning of the day. Most performed differences in clock gene expression we detected in the AP of TGR rats. Expression of per2 was phase delayed and expression bmal1 was phase advanced in the TGR rats in comparison with controls. Genes involved in protein and glucose metabolism were expressed in rhythmic manner in AP of TGR rats with peak levels at night.

Conclusion: 

Results confirmed that TGR rats exerted a higher PRA. Daily profile of clock and metabolic gene expression were different in AP in TGR rats in comparison with control animals.

Research was supported by grants APVV-20-022704, VEGA 1/4328/07 and VEGA 1/4343/07.