Cajaninstilbene acid relaxes rat renal arteries: roles of Ca2+ antagonism and protein kinase C-dependent mechanism.
Cajaninstilbene acid (CSA) is a major active component present in the leaves of Cajanus cajan (L.) Millsp. The present study explores the underlying cellular mechanisms for CSA-induced relaxation in rat renal arteries. Vascular reactivity was examined in arterial rings that were suspended in a Multi Myograph System and the expression of signaling proteins was assessed by Western blotting method. CSA (0.1-10 µM) produced relaxations in rings pre-contracted by phenylephrine, serotonin, 9, 11-dideoxy-9α, 11α-epoxymethanoprostaglandin F(2α) (U46619), and 60 mM KCl. CSA-induced relaxations did not show difference between genders and were unaffected by endothelium denudation, nor by treatment with N(G)-nitro-L-arginine methyl ester, indomethacin, ICI-182780, tetraethylammonium ion, BaCl(2), glibenclamide, 4-aminopyridine or propranolol. CSA reduced contraction induced by CaCl(2) (0.01-5 mM) in Ca(2+)-free 60 mM KCl solution and by 30 nM (-)-Bay K8644 in 15 mM KCl solution. CSA inhibited 60 mM KCl-induced Ca(2+) influx in smooth muscle of renal arteries. In addition, CSA inhibited contraction evoked by phorbol 12-myristate 13-acetate (PMA, protein kinase C agonist) in Ca(2+)-free Krebs solution. Moreover, CSA reduced the U46619- and PMA-induced phosphorylation of myosin light chain (MLC) at Ser19 and myosin phosphatase target subunit 1 (MYPT1) at Thr853 which was associated with vasoconstriction. CSA also lowered the phosphorylation of protein kinase C (PKCδ) at Thr505. In summary, the present results suggest that CSA relaxes renal arteries in vitro via multiple cellular mechanisms involving partial inhibition of calcium entry via nifedipine-sensitive calcium channels, protein kinase C and Rho kinase.
Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China.
Dong-Mei
DM
Zhang
Yong
Y
Li
Wai San
WS
Cheang
Chi Wai
CW
Lau
Shun-Ming
SM
Lin
Qian-Lan
QL
Zhang
Nan
N
Yao
Ying
Y
Wang
Xin
X
Wu
Yu
Y
Huang
Wen-Cai
WC
Ye
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D005905:Glyburide / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D011189:Potassium Chloride / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D012077:Renal Artery / Q000187:drug effects*; D012459:Salicylates / Q000494:pharmacology*; D013267:Stilbenes / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019789:Tetraethylammonium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
C549543:3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid; D012459:Salicylates; D013267:Stilbenes; D000077267:Fulvestrant; D004958:Estradiol; D019789:Tetraethylammonium; D011189:Potassium Chloride; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D005905:Glyburide; D002118:Calcium