Vasodilatation Effects of the Alcohol Extract from Uighur Medicine Ziziphora clinopodioides on Isolated Rat Thoracic Aorta Vessel Rings / 中国药房

ABSTRACT

OBJECTIVE:To study the vasodilatation effects of the alcohol extract from Uighur medicine Ziziphora clinopodioi-des(EEZ)on isolated rat thoracic aorta vessel rings. METHODS:Isolated rat thoracic aorta vessel rings were prepared. There was a group with intact vessel ring endothelium and a group with vessel ring endothelium removed in the test. After preshrinking the ves-sel rings with phenylephrine(PE),EEZ of 100,300,500,700,900 and 1 100 mg/L was added gradually,concentration-vasodila-tation curve was drawn and maximal vasodilatation rate (Emax) and median effective concentration (EC50) were calculated. For the group with vessel ring endothelium removed,after the vessel ring was pretreated with EEZ at EC50 in calcium-free solution or calci-um-free high-potassium solution,CaCl2 of 0.4,0.8,1.2,1.6,2.0 and 2.4 mmol/L was added gradually,and calcium concentra-tion-tension curve was drawn;following the pretreatment of the vessel ring with EEZ at EC50,1 μmol/L PE was added and shrink tension was recorded and vasoconstriction percentages was calculated. RESULTS:EEZ had vasodilatation effect on the vessel ring preshrunk with PE in a concentration and smooth muscle-dependent manner. The group with intact vessel ring endothelium and the group with vessel ring endothelium removed respectively had Emax of (58.18 ± 16.23)% and (73.54 ± 17.21)%,and EEZ EC50 of 773.27 mg/L. For calcium-free high-potassium solution,EEZ could cause the calcium ion-vasoconstriction curve to move to the right obviously;for calcium-free solution,EEZ could inhibit the vasoconstriction caused by PE. CONCLUSIONS:EEZ has vasodi-latation effects by a mechanism which may be related to inhibiting calcium influx and intracytoplasmic calcium release through the inhibition of voltage-dependent calcium channels(VDCCs),and thus interfering intracytoplasmic calcium ion balance.