Cain S M, Chapler C K
Am J Physiol. 1982 Dec;243(6):H1010-7. doi: 10.1152/ajpheart.1982.243.6.H1010.
Blood flow (Q) and O2 uptake (Vo2) were measured in the intact autoperfused left hindlimb (less paw) of anesthetized paralyzed dogs ventilated at constant rate with either room air (normoxia) or 9.1% O2 in N2 (hypoxia) for 20-min periods. One group of 10 dogs was given 3.0 mg/kg phenoxybenzamine (alpha-block) and was subjected to the sequence of normoxia, hypoxia, normoxia. The sequence was repeated after 1.0 mg/kg propranolol (beta-block). A second group of 10 was treated the same but was not given adrenergic blockers (no block). A third group of 10 was made hypoxic only once after the sciatic and femoral nerves to the prepared limb were severed (denervated). Decreased O2 availability during hypoxia limited both total and limb V02 in all cases. Limb Q did not change, but vascular resistance increased in the no-block group with onset of hypoxia and a brisk transient hyperemia occurred with reoxygenation. After both alpha- and beta-block no change occurred in limb resistance with reoxygenation. A similar result was obtained in the denervated limb. These results indicated that the transient hyperemia following hypoxia was the result of altered states of neurally mediated vascular tone, mostly sympathetic, and was not due to local metabolic vasodilation or altered blood levels of catecholamines during a 20-min period of hypoxia.
在以室空气（常氧）或氮气中9.1%氧气（低氧）以恒定速率通气的麻醉性瘫痪犬的完整自体灌注左后肢（不包括爪子）中，测量血流量（Q）和氧气摄取量（V̇o₂），持续20分钟。一组10只犬给予3.0mg/kg酚苄明（α阻断），并经历常氧、低氧、常氧的顺序。在给予1.0mg/kg普萘洛尔（β阻断）后重复该顺序。第二组10只犬接受相同处理但未给予肾上腺素能阻断剂（无阻断）。第三组10只犬在切断制备肢体的坐骨神经和股神经（去神经）后仅经历一次低氧。在所有情况下，低氧期间氧气供应减少限制了总V̇o₂和肢体V̇o₂。肢体Q未改变，但在无阻断组中，随着低氧的开始血管阻力增加，再氧合时出现明显的短暂性充血。在α和β阻断后，再氧合时肢体阻力没有变化。在去神经肢体中也获得了类似的结果。这些结果表明，低氧后的短暂性充血是神经介导的血管张力改变的结果，主要是交感神经介导的，而不是由于局部代谢性血管舒张或低氧20分钟期间儿茶酚胺血水平的改变。
