Patch-clamp whole-cell recording techniques were used to study ATP-induced Cl- current and the effects of Cl- channel blockers on NO release in bovine aortic endothelial cells. ATP evoked an outward rectified Cl- current with a reversal potential of 2973mV. This outward rectified Cl- current was dependent on Ca2+ influx, but not Ca2+ release. In Ca2+-free medium, ATP did not produce the Cl- current; however, subsequent addition of Ca2+ to the medium evoked an ATP-induced outward rectified Cl- current. Furosemide, glibenclamide, and DIDS inhibited ATP-activated Cl- current in a concentrationdependent manner with maximal inhibition of 8874%, 9371%, and 7973%, respectively. The IC50 values of furosemide, glibenclamide, and DIDS were 6.272.6, 29.6712.3, and 21.0713.4mM, respectively. These effects of Cl- channel blockers matched those on NO release from endothelial cells. Our data suggest that ATP-induced Ca2+ entry followed by increased [Ca2+]i activates Ca2+-activated Cl- channels which mediate NO release from endothelial cells. Drug Dev. Res. 57: 000-000, 2003

目的：研究随着糖尿病的发生发展，大鼠主动脉平滑肌对苯肾上腺素等激动剂收缩反应的变化及其可能机制。方法：用链尿菌素诱导糖尿病后，在第2、6、12周，取主动脉环进行实验观察。结果：苯肾上腺素的浓度依赖性收缩反应曲线，与对照相比：在第2周，低浓度时（0.01-0.03μmol·L-1）明显增加（P<0.01），最大反应无明显变化；在第6周，各浓度点均显著增加，且最大收缩反应增加约40%；然而，在第12周1）苯肾上腺素10μmol·L-1引起的最大收缩反应趋向降低（P<0.05），2）在无Ca2+液，也较对照明显减小（P<0.05），3）在无Ca2+液，在尼非地平1μmol·-L-1和苯肾上腺素10μmol·L-1存在下，复Ca2+引起的收缩在两组问的差异未见显著性，4）在正常Krebs‘液，环匹阿尼酸10μmol·L-1引起的收缩反应较对照也显著减小（P<0.001)。结论：（1）在糖尿病的第2周，平滑肌α-1肾上腺素能受体的敏感性增加。（2）糖尿病大鼠主动脉平滑肌对苯肾上腺素收缩反应的异常变化，与通过电压依赖性钙通道的Ca+内流大小、胞内功能性Ca2+池大小及其胞内Ca2+池耗竭后所引起的充电性内流变化密切相关。

Newborn male Wistar rats were treated with nerve growth factor daily by subcutaneous inJection for 2 weeks, and control rats were treated with either cytochrome c or buffered saline. Average body weight of the treated animals was lower than that of the controls during the 2 weeks of treatment, but became simdar to that of the controls thereafter. Tissue levers of norepinephrine were elevated in the brain, adrenal glands, nlesernteric arteries, and vas deferens of the treated animals immediately after the treatment, but became simliar in the three grcalps 2 weeks after tbe terminndon of tbe treatment. Blood pressure and heart tale were measured beginning at 4 weeks of age until 28 becks, when the rats were sacrificed and the mesenteric arteries sampled for morphometric measurements of vessel wall dimensions. Pretreatrnent with nerve growth fac tor did not affect blood pressure, nor heart rate. Stroctural atteration of the three types of mesenteric arteries was also absent in the treated animals. We conclude that even though neonatal treatment of normal Wistar rats with nerve growth factor for 2 weeks induced an elevation of the norepinephrine levels in severat tissues at the end of the treatment period, it was not sufficient to produce hypertension and structural alterations in the blood vessels.

AIM: To investigate the effects of 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) on cell proliferation and apoptosis in ECV304 endothelial cells and related molecular mechanism. METHODS: MTT, Hoechst33258, TUNEL, Flow cytometry, DNA ladder, RT-PCR, Western blot, and electrophoretic mobility shift assay (EMSA) analysis were employed. RESULTS: The 15d-PGJ2 induced apoptosis in ECV304 endothelial cells in a dose-dependent manner (the percentage of apoptosis was enhanced from 10.0%±1.3% to 32.8%±1.6%), which was accompanied by inhibition of NF-κB and AP-1 DNA binding activity, down-regulation of c-myc, upregulation of Gadd45 and p53, and activation of p38 kinase. However, the expression of p21 was found no significant change. CONCLUSION: peroxisome proliferator-activated receptor gamma ligand, 15d-PGJ2, can inhibit proliferation and induce apoptosis in ECV304 endothelial cells through different mechanisms.

1. The effects of chebulinic acid, which has been shown to elicit blood pressure lowering effect in rats, on aortic vascular contraction as well as cardiac contraction were studied in rats. 2. Chebulinic acid had no effect on KCI-induced aortic contraction, but irreversibly inhibited the contractile responses to phenylephrine in an apparently non-competitive manner. Chebulinic acid also inhibited contractile responses of rat aorta to 5-hydroxytryptamine and angiot ensin It. 3. Chebulinic acid inhibited the binding of pH]-prazosin to dog aortic microsomal membranes in a concentration-depen-dent manner with an IC50 value of 0.3dmmol/L Results of saturation binding experiments suggest a mixed mode of inhibition by chebulinic acid (i.e. a decrease in both the maximal number of binding sites and the affinity for prazosin). 4. Chebulinic acid concentration-dependently and reversihly inhibited the maximal left ventricuiar pressure of rat heart in a Langendorff preparation with 50% inhibition occurring at a concentration of 0.3nmol/L. 5. We conclude that chebulinic acid exerts non-specific inhibitory actions in vascular preparations. Its inhibitory effect on cardiac contraction was reversible and three orders of magnitude more potent than that on vascular contraction. We suggest that the hypotensive effect of chehulinic acid is probably mediated via the decrease in cardiac output resulting from reduced left ventricular contraction.