Abstract
We have demonstrated the distribution of nNOS neurons in the brainstem and diencephalon, which was upregulated in hypertensive Dahl-salt sensitive (DSS) rats compared with normotensive DSS rats. In this study, we directly compared nNOS activity in the brainstem and diencephalon between hypertensive DSS and normotensive Sprague-Dawley (SD) rats. The DSS and Dahl-salt resistant (DSR) rats were fed on 8% NaCl food (DSS8% and DSR8%) or 0.4% NaCl (DSS0.4% and DSR0.4%). SD rats were fed only on 0.4% NaCl food (SD0.4%). The level of nNOS activity in the brainstem of SD0.4% was almost the same as that of DSS8%, which had been significantly higher than those of DSS0.4%, DSR0.4% and DSR8% (normotensive Dahl rat strain). Although the level of nNOS activity in the diencephalon of SD0.4% was significantly higher than that of DSS8%, which had been almost the same as those of the normotensive Dahl rat strain. All these results indicated that at normal blood pressure, the nNOS neuronal system in both the brainstem and diencephalon of Dahl rat strain might be downregulated compared with SD rat strain. In hypertensive DSS rats, the nNOS neuronal system specifically in the brainstem seems to be reversed to the level in SD rats, although the nNOS neuronal system in the diencephalon stays to be downregulated compared with SD rats. [J Physiol Sci. 2006;56 Suppl:S95]
