Brain nuclear factor kappa B is involved in the corticotropin-releasing factor-induced central activation of sympatho-adrenomedullary outflow in rats

NF-κB Blockade in Hypothalamic Paraventricular Nucleus Inhibits High-Salt-Induced Hypertension Through NLRP3 and Caspase-1

High-salt-induced inflammation and oxidative stress in the hypothalamic paraventricular nucleus (PVN) contribute to the pathogenesis of salt-sensitive hypertension. In this study, we hypothesized that chronic inhibition of nuclear factor-κB (NF-κB) activity in the PVN delays the progression of hypertension by upregulating anti-inflammatory cytokines, reducing NLRP3 (NOD-like receptor family pyrin domain containing 3) and IL-1β and attenuating p-IKKβ, NF-κB p65 activity and NAD(P)H oxidase in the PVN of salt-sensitive hypertensive rats. Dahl salt-sensitive rats received a high-salt diet (HS, 8 % NaCl) or a normal-salt diet (NS, 0.3 % NaCl) for 6 weeks and were treated with bilateral PVN infusion with either vehicle or pyrrolidine dithiocarbamate (PDTC, 5 μg/h), a NF-κB inhibitor via osmotic minipump. The mean arterial pressure and plasma levels of norepinephrine (NE) and epinephrine (EPI) were significantly increased in high-salt-fed rats. In addition, rats with high-salt diet had higher levels of p-IKKβ, NF-κB p65 activity, Fra-like (Fra-LI) activity (an indicator of chronic neuronal activation), NOX-4 (subunits of NAD(P)H oxidase), NLRP3 and IL-1β, and lower levels of IL-10 in the PVN than normal diet rats. Bilateral PVN infusions of PDTC attenuated these high-salt-induced changes. These findings suggest that high-salt-induced NF-κB activation in the PVN caused hypertension via sympathoexcitation, which are associated with the increases of NLRP3, IL-1β and oxidative stress in the PVN; PVN inhibition of NF-κB activity attenuates NLRP3, IL-1β and oxidative stress in the PVN and thereby attenuates hypertension.

Brain nuclear factor-kappa B activation contributes to neurohumoral excitation in angiotensin II-induced hypertension

AIMS

Angiotensin II (ANG II)-induced inflammatory and oxidative stress responses contribute to the pathogenesis of hypertension. In this study, we determined whether nuclear factor-kappa B (NF-kappaB) activation in the hypothalamic paraventricular nucleus (PVN) increases oxidative stress and contributes to the ANG II-induced hypertensive response.

METHODS AND RESULTS

Rats were infused intravenously with ANG II (10 ng/kg per min) or saline for 4 weeks. These rats received either vehicle or losartan (LOS, 20 microg/h), an angiotensin II type 1 receptor (AT1-R) antagonist; pyrrolidine dithiocarbamate (PDTC, 5 microg/h), a NF-kappaB inhibitor; tempol (TEMP, 80 microg/h), a superoxide scavenger; LOS (20 microg/h), and PDTC (5 microg/h); or TEMP (80 microg/h) and PDTC (5 microg/h), given intracerebroventricularly (ICV) via osmotic minipump. ANG II infusion resulted in increased mean arterial pressure, renal sympathetic nerve activity, plasma proinflammatory cytokines (PIC), norepinephrine, and aldosterone. These rats also had higher levels of Fra-LI (an indicator of chronic neuronal activation), PIC, phosphorylated IKKbeta, NF-kappaB subunits, AT1-R, superoxide, and gp91phox (a subunit of NADP(H) oxidase) and lower levels of IkappaBalpha in the PVN than control animals. ICV treatment with LOS, PDTC, or TEMP attenuated these changes, and combined treatment with ICV LOS and PDTC, or ICV TEMP and PDTC prevented these ANG II-induced hypertensive responses.

CONCLUSION

These findings suggest that an ANG II-induced increase in the brain renin-angiotensin system activates NF-kappaB in the PVN and contributes to sympathoexcitation in hypertension. The increased superoxide in the PVN contributes to NF-kappaB activation and neurohumoral excitation in hypertension.