Sun D, Huang A, Koller A, Kaley G
Department of Physiology, New York Medical College, Valhalla 10595.
J Appl Physiol (1985). 1994 May;76(5):2241-7. doi: 10.1152/jappl.1994.76.5.2241.
We aimed to test the hypothesis that as a consequence of short-term daily bouts of exercise the control of arteriolar smooth muscle by endothelium is altered. Rats ran on a treadmill once a day, 5 days/wk, for 2-4 wk (with gradually increasing intensity, up to 26 min at 22 m/min at a 1% grade by the beginning of the 3rd wk and up to 38 min at 28 m/min at a 2% grade by the beginning of the 4th wk) while a control group remained sedentary (SED). Cannulated and pressurized arterioles of rat gracilis muscle developed spontaneous myogenic tone, which was slightly enhanced in exercised (EX) compared with SED rat arterioles. At 80 mmHg pressure, the passive (Ca(2+)-free solution) and active diameters of SED and EX rat arterioles were 105.4 +/- 3.8 and 55.1 +/- 2.3 microns and 107.1 +/- 3.4 and 50.2 +/- 2.2 microns, respectively. Dose-dependent dilations to sodium nitroprusside (10(-8)-10(-6) M) and constrictions to norepinephrine (10(-8)-10(-6) M) were not affected in EX arterioles, whereas dilations to adenosine (10(-6)-10(-4) M) were significantly reduced. In contrast, dose-dependent dilations to acetylcholine (ACh; 5 x 10(-9)-10(-7) M) and L-arginine [precursor of nitric oxide (NO); 10(-4)-10(-3) M] were significantly enhanced (by 33-78 and 57-75%, respectively) in arterioles of EX compared with those of SED rats. Responses of arterioles to sodium nitrite were not different in SED and EX groups.(ABSTRACT TRUNCATED AT 250 WORDS)
由于短期每日进行运动，内皮对小动脉平滑肌的控制会发生改变。大鼠每周5天，每天在跑步机上跑步2 - 4周（强度逐渐增加，到第3周开始时以22米/分钟的速度在1%坡度下跑26分钟，到第4周开始时以28米/分钟的速度在2%坡度下跑38分钟），而对照组保持 sedentary（SED）状态。大鼠股薄肌的插管加压小动脉产生自发性肌源性张力，与SED大鼠的小动脉相比，运动（EX）大鼠的小动脉自发性肌源性张力略有增强。在80 mmHg压力下，SED和EX大鼠小动脉的被动（无钙溶液）直径和主动直径分别为105.4±3.8微米和55.1±2.3微米以及107.1±3.4微米和50.2±2.2微米。EX小动脉对硝普钠（10⁻⁸ - 10⁻⁶ M）的剂量依赖性舒张和对去甲肾上腺素（10⁻⁸ - 10⁻⁶ M）的收缩不受影响，而对腺苷（10⁻⁶ - 10⁻⁴ M）的舒张则显著降低。相反，与SED大鼠相比，EX大鼠小动脉对乙酰胆碱（ACh；5×10⁻⁹ - 10⁻⁷ M）和L - 精氨酸[一氧化氮（NO）的前体；10⁻⁴ - 10⁻³ M] 的剂量依赖性舒张显著增强（分别增强33 - 78%和57 - 75%）。SED组和EX组小动脉对亚硝酸钠的反应没有差异。（摘要截断于250字）
