Abstract: Objective To investigate whether brain reactive oxygen species mediate sympathoexcitation and arterial pressure
elevation in DOCA-salt hypertensive rats. Methods DOCA-salt hypertensive model was established in male SD rats by
subcutaneous injection of DOCA after uninephrectomy and drinking 1% NaCl solution for 4 weeks. The baseline mean arterial
pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded in the rats under mild anesthesia,
and MAP changes following intravenous hexamethonium injection were observed. The responses of MAP, HR and RSNA to
intracerebroventricular administration of tempol (20 μmol/L in 10 μl) were evaluated; plasma NE level was measured with
ELISA, and ROS level and NAD(P)H oxidase activity in the hypothalamus were detected using chemiluminescence assay.
Results MAP and plasma NE levels were significantly increased in DOCA-salt rats as compared with those in the control
group (P<0.01). In DOCA-salt hypertensive rats, intravenous hexamethonium injection induced a blood pressure reduction
240% of that in control rats, and significantly increased the levels of superoxide anion and NAD(P)H oxidase activity in the
hypothalamus. Intracerebroventricular microinjection of tempol also resulted in more significant changes of MAP, HR and
RSNA in DOCA-salt rats than in the control group (P<0.01). Conclusion Sympathoexcitation due to increased NAD(P)H
oxidase-derived ROS levels in the hypothalamus may mediate arterial pressure elevation in DOCA-salt hypertensive rats.