Liang I Y, Stone H L
J Appl Physiol Respir Environ Exerc Physiol. 1983 Apr;54(4):1057-62. doi: 10.1152/jappl.1983.54.4.1057.
Diastolic coronary resistance (DCR) was studied in 10 conscious dogs in the untrained (UT) and partially trained (PT) condition. The PT regime consisted of treadmill running 5 days/wk for 4-5 wk. Left circumflex coronary flow, aortic pressure, and heart rate were measured, and diastolic coronary resistance (DCR) was calculated. Adrenergic blockade was achieved with propranolol (1 mg/kg, iv) (beta B) and phentolamine (1 mg/kg, iv) (alpha B). During submaximal exercise in the UT condition, DCR fell from a resting value of 3.84 +/- 0.24 Torr . ml-1 . min with increasing work load to 1.57 +/- 0.12 Torr . ml-1 . min at 6.4 km/h (speed)/16% (grade). The decrease in DCR during submaximal exercise was greater in the PT than in the UT condition. DCR following alpha-adrenergic blockade was not significantly changed in the UT and PT conditions (e.g., at 6.4 km/h (speed)/16% (grade), 1.10 +/- 0.141 vs. 1.03 +/- 0.107 Torr . ml-1 . min, whereas following beta-adrenergic blockade, DCR was larger in the UT compared with the PT condition (e.g., at 6.4 km/h (speed)/16% (grade), 2.03 +/- 0.091 vs. 1.73 +/- 0.073 Torr . ml-1 X min). Myocardial oxygen consumption was not significantly different in the PT and UT conditions, indicating no difference in metabolism with partial training. The present study suggests that during submaximal exercise in the PT condition there is a change in the neurogenic control of the coronary vasculature by a reduction in sympathetic neural activity on the coronary resistance vessels.
在10只清醒犬处于未训练（UT）和部分训练（PT）状态下，研究了舒张期冠状动脉阻力（DCR）。PT方案包括每周5天、持续4 - 5周的跑步机跑步。测量左旋冠状动脉血流、主动脉压和心率，并计算舒张期冠状动脉阻力（DCR）。使用普萘洛尔（1mg/kg，静脉注射）（β受体阻滞剂）和酚妥拉明（1mg/kg，静脉注射）（α受体阻滞剂）实现肾上腺素能阻断。在UT状态下的次最大运动期间，随着工作负荷增加，DCR从静息值3.84±0.24 Torr·ml⁻¹·min降至6.4 km/h（速度）/16%（坡度）时的1.57±0.12 Torr·ml⁻¹·min。PT状态下次最大运动期间DCR的降低幅度大于UT状态。在UT和PT状态下，α肾上腺素能阻断后的DCR无显著变化（例如，在6.4 km/h（速度）/16%（坡度）时，分别为1.10±0.141和1.03±0.107 Torr·ml⁻¹·min），而β肾上腺素能阻断后，UT状态下的DCR大于PT状态（例如，在6.4 km/h（速度）/16%（坡度）时，分别为2.03±0.091和1.73±0.073 Torr·ml⁻¹·min）。PT和UT状态下心肌耗氧量无显著差异，表明部分训练对代谢无差异。本研究表明，在PT状态下的次最大运动期间，冠状动脉血管的神经源性控制发生变化，冠状动脉阻力血管上的交感神经活动减少。
