长期限食对大鼠尾动脉P_2X_1受体和α_1受体介导血管收缩反应的影响

Effects of long food-restriction on P_2X_1 and α_1 receptors-mediated vasoconstriction in rat caudal artery

目的研究长期限食对大鼠尾动脉P2X1受体和α1受体介导血管收缩反应的影响。方法将Wistar大鼠分为对照组和限食组,对照组大鼠自由饮食,限食组大鼠每天给予正常日饮食量的50%,3周后制备大鼠离体尾动脉环标本,记录α,β-亚甲基ATP(α,β-MeATP)和去甲肾上腺素(NA)诱发的等长收缩反应。结果与对照组比较,长期限食后α,β-MeATP和NA诱发大鼠尾动脉的收缩反应明显增强(P<0.01),10-4mol/Lα,β-MeATP和NA诱发的收缩反应与对照组相比,分别增大了34.01%和25.85%。限食前后α,β-MeATP和NA诱发最大收缩反应的比值分别为0.78和0.83,两种血管激动剂的半数有效浓度值在限食前后均无明显改变(P>0.05)。结论长期限食明显增强大鼠尾动脉P2X1受体和α1受体介导的收缩反应,但对两种激动剂的受体结合率、两种受体介导最大收缩反应的比值以及血管的肌性收缩反应无明显影响。

Objective To observe the effect of long food-restriction on the vasoconstriction responses mediated by P2XI purinoceptor anda -adrenoceptor in rat caudal arteries. Methods Wistar rats were divided into two groups： control group and food-restriction group. Control group rats had free diet, then food-restricted rats were given approximately 50% of their normal daily food intake. After 3 weeks, isometric contractile responses induced by a-MeATP and NA in caudal artery were recorded. Results Compared with control group, long food-restriction significantly increased the caudal artery contraction reactions induced by a-MeATP and NA （P 〈 0.01）; the vasoconstriction mediated by 10 mol/L a,β-MeATP and NA increased by 34.01% and 25.85% respectively. The values of Emaxa,β-MeATP/Emax.NA were 0.78 and 0.83 before and after food-restriction. The long food-restriction did not affect the ECho values of a,β- MeATP and NA in the rat caudal arteries. Conclusion Long food-restriction increases the vasoconstriction regulated by P2X1 purinoceptors and a-adrenoceptors in rat caudal artery, while their receptors binding rate, the ratio of their maximum constriction, and the muscle contraction response are not chaned durin the food restriction.