Abnormal central serotonergic activities in spontaneously hypertensive rats (SHR).

We employed spontaneously hypertensive rats (SHR) to explore a possible role of central serotonergic activity in hypertension. The activities of serotonergic nervous system were assessed by measuring the serotonin turnover rates in rats treated with probenecid. Serotonin turnover rates in telencephalon and hypothalamus/thalamus of SHR were significantly lowered as compared to WKY rats whereas those in cerebellum of SHR were significantly elevated than those of WKY rats. There was no significant difference in serotonin turnover rates in midbrain and pons/medulla of SHR and WKY rats. These results suggest that the abnormal turnover rates of serotonin in brain may be one of the underlying neuronal factors for the manifestation of hypertension in SHR.