Reactive oxygen species (ROS) in the brain are involved in the pathogenesis of 
hypertension. Epigallocatechin-3-O-gallate (EGCG), one of the active compounds 
in green tea, has anti-oxidant, anti-inflammatory and vascular protective 
properties. This study was designed to determine whether chronic infusion of 
EGCG into the hypothalamic paraventricular nucleus (PVN) attenuates ROS and 
sympathetic activity and delays the progression of hypertension by up-regulating 
anti-inflammatory cytokines, reducing pro-inflammatory cytokines (PICs) and 
decreasing nuclear factor-kappa B (NF-κB) activity, as well as restoring the 
neurotransmitters balance in the PVN of spontaneously hypertensive rats (SHR). 
Adult normotensive Wistar-Kyoto (WKY) rats and SHR received bilateral PVN 
infusion of EGCG (20μg/h) or vehicle via osmotic minipumps for 4 weeks. SHR 
showed higher mean arterial pressure, plasma proinflammatory cytokines and 
circulating norepinephrine (NE) levels compared with WKY rats. SHR also had 
higher PVN levels of the subunit of NAD(P)H oxidase (gp91phox), ROS, tyrosine 
hydroxylase, and PICs; increased NF-κB activity; and lower PVN levels of 
interleukin-10 (IL-10) and 67kDa isoform of glutamate decarboxylase (GAD67) than 
WKY rats. PVN infusion of EGCG attenuated all these changes in SHR. These 
findings suggest that SHR have an imbalance between excitatory and inhibitory 
neurotransmitters, as well as an imbalance between pro- and anti-inflammatory 
cytokines in the PVN. Chronic inhibition of ROS in the PVN restores the balance 
of neurotransmitters and cytokines in the PVN, thereby attenuating hypertensive 
response and sympathetic activity.