Abstract
We have demonstrated that the brain nNOS system is upregulated in hypertensive Dahl salt-sensitive (DS) rats than in normotensive DS rats. In the present study, we compared the number of nNOS neurons in the brain between DS rats, Dahl salt-resistant (DR) rats, and Sprague-Dawley (SD) rats. The DS and DR rats were divided into two groups: one fed on 8% NaCl food (the DS8% and DR8% groups) and the other fed on 0.4% NaCl food (the DS0.4% and DR0.4% groups). SD rats were fed only on 0.4% NaCl food. Immunohistochemical study showed that there was no significant difference in the distribution of nNOS neurons in the brainstem and hypothalamus between those five rat groups. The number of nNOS neurons in the brainstem was significantly greater in the SD group than in the DR0.4% group, while no significant difference was found in the number of nNOS neurons in the brainstem and hypothalamus between the DR0.4% and DR8% groups, or between the DR0.4% and DS0.4% groups. It might be possible that the brain nNOS system is not upregulated in the hypertensive DS8% group but downregulated in the normotensive rat groups (DS0.4%, DR0.4%, and DR8%). [Jpn J Physiol 55 Suppl:S191 (2005)]
