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Superoxide anions involved in sympathoexcitation and pressor effects of salusin‐ β in paraventricular nucleus in hypertensive rats
Author(s) -
Sun H.J.,
Zhang L.L.,
Fan Z.D.,
Chen D.,
Zhang L.,
Gao X.Y.,
Kang Y.M.,
Zhu G.Q.
Publication year - 2014
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12188
Subject(s) - apocynin , endocrinology , medicine , chemistry , superoxide , rostral ventrolateral medulla , nadph oxidase , nad(p)h oxidase , blood pressure , oxidative stress , heart rate , biochemistry , enzyme
Aims Salusin‐ β in paraventricular nucleus ( PVN ) increases renal sympathetic nerve activity ( RSNA ), mean arterial pressure ( MAP ), heart rate ( HR ) and arginine vasopressin ( AVP ) release in hypertensive rats but not in normal rats. The present study was designed to investigate the downstream molecular mechanism of salusin‐ β in the PVN in hypertension. Method Renovascular hypertension was induced by two‐kidney, one‐clip (2K1C) in male SD rats. Acute experiments were carried out 4 weeks after 2K1C or sham operation under anaesthesia. Results MrgA1 mRNA expression and salusin‐ β level in the PVN as well as plasma salusin‐ β level were increased in 2K1C rats. Bilateral PVN microinjection of salusin‐ β increased the RSNA, MAP and HR in 2K1C rats, which were abolished by the pre‐treatment with polyethylene glycol–superoxide dismutase (PEG‐SOD), the superoxide anion scavenger tempol, the NAD(P)H oxidase inhibitor apocynin or the protein kinase C (PKC) inhibitor chelerythrine chloride (CLC), but not affected by the AT 1 receptor antagonist losartan, the Mas receptor antagonist A‐779, the NOS inhibitor L‐NAME or the GABA A and GABA B receptor antagonists gabazine+CGP‐35348. Salusin‐ β ‐induced increases in superoxide anion level and NAD(P)H oxidase activity in the PVN were abolished by the PVN pre‐treatment with CLC. Salusin‐ β increased AVP levels in rostral ventrolateral medulla and plasma, which were prevented by the pre‐treatment with PEG‐SOD, apocynin or CLC in 2K1C rats. Salusin‐ β augmented the enhanced activity of PKC in the PVN in 2K1C rats. Conclusion Protein kinase C‐ NAD (P)H oxidase‐superoxide anions pathway in the PVN is involved in salusin‐ β ‐induced sympathetic activation, pressor response and AVP release in renovascular hypertension.