The effect of hypothermia on the vasoconstriction and vasodilatation and concerned with vasoactive drugs / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the changes of vasoconstriction and vasodilatation under different temperature conditions and the protective effects of Vitamin E (Vit E) against endothelial injury induced by hypothermia.</p><p><b>METHODS</b>The tail arterial rings were prepared for isometric tension recording using multi wire myograph system. The effect of temperature on relaxation and construction was evaluated. Incubate the arterial rings with different concentration of Vit E when they were exposed to hypothermia, then acetylcholine (ACh)-induced endothelium-dependent relaxation was investigated to evaluate the activity of endothelial.</p><p><b>RESULTS</b>(1) The hypothermia could enhanced the dose-dependent construction induced by PE in mice tail artery. (2) Exposure to hypothermia also resulted in increase of sodium nitroprusside (SNP)-induced re-After incubation with Vit E, the vascular relaxation responses to ACh increased in an endothelium-dependent manner, when compared with the hypothermia-treated group.</p><p><b>CONCLUSION</b>The vascular function of constriction was attenuated by hypothermia, while the relaxation was increased. Vit E could prevent the hypothermia-induced decrease in vascular endothelial cells.</p>

The selective dilatation effects of iptakalim on basilar and pulmonary arterioles in high-altitude hypoxic rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the selective dilatation effects of iptakalim (Ipt) on basilar and pulmonary arterioles, and endothelial cell function of these arterioles in hypoxic rats.</p><p><b>METHODS</b>SD male rats were divided into 2 groups:control and hypoxic group fed in normobaric hypoxic environment (O2 7.8%, 8 h). Arteriole rings about (204 + 5) pm were isolated and the tension of hypoxic arterioles pre-contracted by 6 nmol/L endothelin-1 (ET-1) was observed with wire myograph system model (DMT 610 m). The relaxing response of hypoxic arterioles induced by different concentration of Ipt were detected and endothelial activity was also tested by acetylcholine.</p><p><b>RESULTS</b>10(5) mol/L acetylcholine (ACh)-mediated vasodilatation of basilar and pulmonary arterioles was greatly reduced in the hypoxic group than those in control group (P < 0.05). Compared with normal group, a novel ATP-sensitive potassium channel opener Ipt at the concentration ranging from 10(-11) mol/L to 10(3) mol/L, caused stronger dose dependent vasodilatation on hypoxic pulmonary arterioles, and there was no significant difference between control and hypoxic basilar arterioles.</p><p><b>CONCLUSION</b>The endothelial function of basilar and pulmonary arterioles was damaged under hypoxic state, and Ipt selectively increased dilatation effects on hypoxic pulmonary arterioles, but not on hypoxic basilar arterioles which could improve high altitude pulmonary edema pathological state and be the novel drug in the treatment of pulmonary hypertension.</p>

The selective dilatation effects of iptakalim on pulmonary arterioles in hypoxic pulmonary hypertensive rat / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the selective dilatation effects of iptakalim (Ipt), a novel ATP-sensitive potassium channel opener, on pulmonary arterioles in hypoxic pulmonary hypertensive rat.</p><p><b>METHODS</b>SD male rats were divided into 3 groups, control group, the rest were fed in hypoxic and normobaric environment (O2 10% +/- 0.5%, 8 h/d and 6 d/week) and divided into hypoxia group and hypoxia plus acetazolamide (Acz) group (hypoxic rats were treated with ig acetazolamide (Acz) 80 mg x kg(-1) d(-1)) . After 12 weeks, pulmonary arteriole rings about (197 +/- 4) microm were isolated and the tension of hypoxic pulmonary arterioles pre-contracted by 6 nmol/L endothelin-1 (FT-1) was observed with wire myograph system model (DMT 610 m). The relaxing response of hypoxic pulmonary arterioles induced by different concentration of Ipt were detected and endothelial activity was also tested by acetylcholine.</p><p><b>RESULTS</b>10(-5) mol/L acetylcholine (ACh)-mediated vasodilatation was greatly reduced in the hypoxic group than those in control group (P < 0.01) and there was no significant difference between Acz treatment group and control group (P > 0.05). Ipt at the concentration ranging from 10(-11) mol/L to 10(-4) mol/L, caused dose dependent vasodilation on both hypoxic pulmonary arterioles and Acz treatment group (P > 0.05), but not on normal group.</p><p><b>CONCLUSION</b>The endothelial function of pulmonary arterioles was damaged under hypoxic pulmonary hypertensive state, and Ipt showed selective dilatation effects on hypoxic pulmonary arterioles. Acz could improve the dysfunction of endothelial cells induced by hypoxic pulmonary hypertensive state, which didn't affect the selective dilatation effects of Ipt on hypoxic pulmonary arterioles.</p>