Effects of Panax notoginseng saponins on receptor-operated Ca2+ channels in vascular smooth muscle.
The effects of saponins of Panax notoginseng (PNGS) on the alpha-adrenoceptor agonists-induced contractile responses and Ca2+ movement were studied in dog mesenteric artery (MA) and saphenous vein (SV). PNGS reduced the contractions and the 45Ca influx (from 0.36 +/- 0.03 to 0.14 +/- 0.05 mumol.g-1 wet strip) induced by phenylephrine (Phe) without effect on KCl-induced contraction and 45Ca influx which were nearly completely inhibited by nifedipine 0.1 mumol.L-1. PNGS did not change the 45Ca efflux induced by Phe and the Kd value (from 0.76 +/- 0.04 to 0.72 +/- 0.15 nmol.L-1) for [3H]prazosin binding on the microsomal membrane isolated from MA. Our results indicate that PNGS selectively inhibits Ca2+ entry through receptor-operated Ca2+ channel.
Guan
Y Y
YY
Department of Pharmacology, Sun Yat-Sen University of Medical Sciences, Guangzhou.
Kwan
C Y
CY
He
H
H
Sun
J J
JJ
Daniel
E E
EE
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects; D004285:Dogs; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D017538:Mesenteric Artery, Superior / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D012501:Saphenous Vein / Q000187:drug effects; D012503:Saponins / Q000302:isolation & purification / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D015220:Calcium Channels; D004365:Drugs, Chinese Herbal; C027816:San-Chi; D012503:Saponins