Effects of total flavonoids of Hippophae rhamnoides L. on intracellular free calcium in cultured vascular smooth muscle cells of spontaneously hypertensive rats and Wistar-Kyoto rats.
OBJECTIVE
To explore the effects of total flavonoids of Hippophae rhamnoides L. (TFH), quercetin (Que) and isorhamnetin (Isor) on the intracellular free calcium ([Ca(2+)](i)) in vascular smooth muscle cells (VSMC) of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY).


METHODS
Fluo 3-acetoxymethylester (Fluo-3/AM) was used to observe the effects of TFH (100 mg/L) and its essential monomers, namely Que (10(-4) mol/L) and Isor (10(-4) mol/L) on changes of [Ca(2+)](i) in cultured SHR and WKY VSMC (abbr. to Ca-SHR & Ca-WKY) following exposure to high K(+), norepinephrine (NE) and angiotensin II (Ang II), and to compare with the effects of verapamil (Ver).


RESULTS
(1) TFH, Que and Isor had inhibitory effects on resting Ca-SHR (P < 0.05), but had no significant effects on Ca-WKY (P > 0.05). (2) High K(+) could increase Ca-SHR more significantly than Ca-WKY (P < 0.05); TFH, Que and Isor could inhibit the elevation of [Ca(2+)](i) induced by high K(+)-depolarization, with the effects similar to that of Ver, and the effect on Ca-SHR was more significant than that on Ca-WKY (P < 0.05). (3) NE and Ang II could increase Ca-SHR more significantly than Ca-WKY (P < 0.05), TFH, Que and Isor had remarkably inhibitory effect on the elevation of Ca-SHR and Ca-WKY induced by NE or Ang II. (4) In the absence of extracellular Ca(2+), TFH, Que and Isor also had certain inhibitory effect on Ca-SHR and Ca-WKY induced by NE, and the effect on the former was more significant than that on the latter (P < 0.05).


CONCLUSIONS
TFH, Que and Isor might decrease the levels of [Ca(2+)](i) in VSMCs by blocking both voltage-dependent calcium channels (VDC) and receptor-operated calcium channels (ROC) in physiological or pathological state, which may be one of the important mechanisms of their hypotensive and protective effects on target organs in patients with hypertension.
Zhu
Fu
F
Cardiovascular Department, Nanhui District Central Hospital, Shanghai 201300. zhufu@medmail.com.cn
Huang
Bo
B
Hu
Chun-yan
CY
Jiang
Qing-yuan
QY
Lu
Zhen-guo
ZG
Lu
Ming
M
Wang
Mei-hua
MH
Gong
Min
M
Qiao
Chun-ping
CP
Chen
Wei
W
Huang
Pan-hua
PH
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000032:analysis*; D002478:Cells, Cultured; D005419:Flavonoids / Q000494:pharmacology*; D044948:Flavonols / Q000494:pharmacology; D031281:Hippophae; D006973:Hypertension / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000737:chemistry* / Q000166:cytology*; D009638:Norepinephrine / Q000494:pharmacology; D011794:Quercetin / Q000494:pharmacology / Q000031:analogs & derivatives; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014700:Verapamil / Q000494:pharmacology
D005419:Flavonoids; D044948:Flavonols; C047368:3-methylquercetin; D000804:Angiotensin II; D011794:Quercetin; D014700:Verapamil; D002118:Calcium; D009638:Norepinephrine