Thursday, July 14, 2011

Dietary salt enhances angiotensin-II-induced superoxide formation in the rostral ventrolateral medulla

Autonomic neuroscience, basic and clinical 2010 Jun 24;155(1-2):14-8. Epub 2010 Jan 6.
Valdir A. Braga

In this article the authors investigated the association of dietary salt and angiotensin-II infusion on hypertension and superoxide formation in the RVLM. Ang-II or saline was subcutaneously infused to male Wistar rats for 14 days. Two different doses of salt was given in the drinking water. As expected on the 15th day rats that received Ang-II and low salt in water exhibited higher levels of baseline arterial blood pressure than rats that received saline and low salt. Rats that received Ang-II and high salt had a significantly greater hypertension compared to Ang-II and low salt. On the other hand, rats treated with saline and high salt or saline and low salt did not become hypertensive. In addition the above treatment rats that are administrated with hexamethonium, a ganglionic blocker evoked larger decreases in mean arterial pressure in rats treated with Ang-II and high salt and rats treated with Ang-II and low salt. Dihydroethidium technique was used to measure superoxide formation in the RVLM which was greater in rats treated with Ang-II and high salt, than withAng-II and low salt and saline and high salt. These findings show that dietary salt provokes Ang-II-derived superoxide formation in the RVLM, resulting in a more severe hypertension. The authors believe that this effect could be mediated by an increase in inputs within the forebrain–PVN–RVLM axis.

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