Abstract
The present study was performed to examine the antihypertensive effect of neferine
in hypertensive rats and its relaxant mechanisms in isolated rat thoracic aorta. The
antihypertensive effect was evaluated by tail-cuff methods on NG-nitro-L-arginine methyl ester (L-NAME) (40 mg/kg BW) 4-week hypertensive-induced
hypertensive rats. The vasorelaxant effect and its mechanisms were studied by the
organ bath technique in the thoracic aorta isolated from normotensive rats. The results
indicated that the treatment of neferine (1 mg/kg and 10 mg/kg) markedly decreased
the systolic blood pressure (SBP) when compared with the hypertension group (137.75 ± 10.14 mmHg
and 132.23 ± 9.5 mmHg, respectively, p < 0.001), without affecting the heart rate.
Moreover, neferine (10−12 − 10−4 M) exhibited concentration-dependent vasorelaxation in endothelium-intact rings (Emax values = 98.95 ± 0.66% and pD2 = 7.93 ± 0.28) and endothelium-denuded rings (Emax values = 90.61 ± 1.91% and pD2 = 6.85 ± 0.36). The effects of neferine were reduced by pre-incubation with L-NAME
and 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ) but not with pre-incubation
with indomethacin and K+channel blockers. Neferine attenuated the contractions induced by phenylephrine and
caffeine in a Ca2+-free solution and also inhibited in CaCl2- and phenylephrine-induced contracted rings. Our study suggests that neferine exhibited
hypertensive potential, induced vasorelaxation through the endothelium nitric oxide
synthase (eNOS)/nitric oxide (NO)/soluble guanylyl cyclase (sGC) pathway and involved
the modulation of Ca2+ influx through Ca2+ channels and intracellular Ca2+ release from the sarcoplasmic reticulum.
Key words
endothelium-dependent - endothelium-independent - hypertension - neferine - nelumbonaceae
-
Nelumbo nucifera
- rat aorta vasorelaxation