[Effect of tetramethyl pyrazine on coronary vasoconstriction induced by endothelin-1 in dogs].
The purpose of this study was to determine the antagonistic effect of tetramethyl pyrazine (TMP), a sort of chinese herbal medicine, on coronary vasoconstriction induced by endothelin-1 (ET-1) in closed chest dogs. ET-1 at doses of 50, 75 and 100 pmol was selectively administered into left main coronary artery and coronary angiogram was performed in 1, 3 and 10 minutes after intracoronary administration of ET-1. After a 60 minute interval ET-1 administration and coronary angiogram were repeated in two groups in group A with 5 dogs intravenous infusion of saline solution was administered while in group B with 4 dogs TMP was infused at a dose of 80 mg/kg. Blood pressure of intra-femoral artery, heart rate and ECG were monitored during the experiment. The study demonstrated that coronary vessel diameter significantly decreased by 17% (P < 0.02) in group A and 20% (P < 0.02) in group B, associated with ischemia in ECG (4/5 in group A and 3/4 in group B) after intracoronary administration of ET-1. Endothelin-1 induced coronary vasoconstriction and ischemic changes in ECG were significantly inhibited by intravenous TMP. The coronary diameter increased by 20% (P < 0.03) after administration of TMP, comparing with the control group. Heart rate had an increased response to TMP. In conclusion this study demonstrated that intracoronary administration of ET-1 caused significant myocardial ischemia through coronary vasoconstriction, which was inhibited by TMP. TMP significantly dilated coronary artery.
Pu
Z
Z
PUMC Hospital, CAMS and PUMC, Beijing.
Zhu
W
W
Jing
Z
Z
Zeng
Z
Z
Zuo
W
W
D000818:Animals; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000187:drug effects*; D004285:Dogs; D019332:Endothelin-1 / Q000037:antagonists & inhibitors*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000503:physiopathology; D011719:Pyrazines / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D019332:Endothelin-1; D011719:Pyrazines; D014665:Vasodilator Agents; C017953:tetramethylpyrazine