We examined the endothelium-dependent relaxation response to acetylcholine (Ach) in treptozotocin-induced diabetic rat aorta at the stages of 2- and 6-wks' duration in vitro, and compared with another two groups which were treated with dietary supplement of 0.1% Aminoquanidine (AG) and 0.5% Erigeron breviscapus(EB) from l-week of diabetes induction. At the stage of 2-wks' duration of diabetes, relaxation responses to lower concentrations of Ach in 0.3uM phenylepherineprecontracted aortas were diminished significantly (Pc0.05) compared with agematched control, but the maximal relaxation of Ach remained unchanged. At the stage of 6-wks' duration, diabetes caused an approximately 60% (P<0.001) deficit in maximum relaxation, and this was significantly (P<0.001) prevented in AG and EB treated groups. There was an approximately 40% enhancement in the maximum contractile response to phenylepherine with diabetes (P<0.5), which was unaffected significantly by AG and EB treatments. The data suggest that the defective endothelium-dependent relaxation in diabetic rat aorta occurred as early as 2-wks' duration of diabetes, and the treatments of AG and EB could protect vascular endothelium although the deficits in vascular smooth muscle contractile responses were not protected.

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

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.