Dual effects of sodium aescinate on vascular tension in rat thoracic aorta.
OBJECTIVE
Sodium aescinate (SA) is used as a vasoactive drug in clinical treatment. This study was designed to investigate the effects of SA on rat isolated thoracic aorta and the possible mechanisms.


METHODS
Isometric tension was recorded in response to drugs in organ bath.


RESULTS
The effects of SA obeyed an all-or-nothing response. SA in relatively low dose (> or = 50 microg/ml) had an endothelium-independent contractile effect in rat aorta (P<0.01), which depended on extracellular Ca(2+) influx via L-type Ca(2+) channel (P<0.05). SA in relatively high dose (> or = 100 microg/ml) also induced vasoconstriction in Ca(2+)-free medium (P<0.01), which was independent of the activity of inositol-1,4,5-trisphosphate receptor (IP(3)R), ryanodine receptor (RYR), and protein kinase C (PKC). SA in relatively high dose (> or = 100 microg/ml) dilated both endothelium-intact and endothelium-denuded aortic rings precontracted by phenylephrine (PE) or KCl (each P<0.01). SA inhibited extracellular Ca(2+) influx induced by PE or KCl (each P<0.01) and had no activation effect on K(+) channels on vascular smooth muscle. The relaxant effect of SA partly depended on the activity of NO synthase but not on the activity of cyclooxygenase.


CONCLUSIONS
Taken together, this study indicated that SA had dual effects on vascular tension in rat isolated thoracic aorta.
Li
Xia
X
Department of Neurology, The First Affiliated Hospital, College of Medicine, Zhejiang University, PR China.
Chen
Guo-Ping
GP
Li
Liang
L
Wang
Kai-Jun
KJ
Zhang
Bi-Qi
BQ
Hu
Shen-Jiang
SJ
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects; D004928:Escin / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D004928:Escin