Differences in direct effects of adrenergic stimuli on coronary, cutaneous, and muscular vessels.
Differences in direct effects of adrenergic stimuli on coronary, cutaneous, and muscular vessels.
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肾上腺素刺激对冠状血管、皮肤血管和肌肉血管的直接影响存在差异。
DOI：
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发表时间：
1972
影响因子：
15.9
通讯作者：
H. Mayer
中科院分区：
文献类型：
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作者：
A. Mark;F. Abboud;P. Schmid;D. Heistad;H. Mayer
在静脉内给予普萘洛尔（2 mg/kg）后，比较了肾上腺素能刺激对犬冠状血管的直接影响与对皮肤（后爪）和骨骼肌（股薄肌）血管的影响，普萘洛尔是一种选择性心肌β受体阻滞剂，可最大限度地减少心肌刺激对冠状血管阻力的间接影响。左回旋冠状动脉，胫前动脉和股薄动脉分别灌注，但同时在恒定流量。灌注压、左心室压和dP/dt。记录心率。每张床的灌注压变化反映了血管阻力的变化。与对皮肤和肌肉血管的影响相比，交感神经刺激、去甲肾上腺素和苯肾上腺素对冠状血管的直接收缩作用最小。随后阻断血管β受体并不增加收缩反应。血管紧张素，一种非肾上腺素能刺激，产生显着的冠状血管收缩，超过了皮肤和近似的肌肉。这些结果表明，与皮肤和肌肉血管相比，冠状血管中α肾上腺素能受体缺乏。冠状动脉和皮肤血管对异丙肾上腺素的直接扩张反应相似，但在肌性血管中更大。对硝酸甘油（一种非肾上腺素能扩张剂）的反应在骨骼肌中也更大。因此，异丙肾上腺素对三个床的作用差异可能反映了对扩张剂刺激的反应性差异，而不是β受体密度的差异。与去甲肾上腺素相反，肾上腺素对冠状动脉血管的主要直接作用是通过激活血管β受体介导的扩张。由α受体刺激引起的收缩效应被普萘洛尔所揭示。最后，激动剂在刺激冠状血管β受体中的效力顺序和用心得安选择性β受体阻滞的证明表明，冠状血管中的β受体与外周血管中的β受体相似，而不是心肌中的β受体。
Direct effects of adrenergic stimuli on coronary vessels in dogs were compared with effects on vessels to skin (hind paw) and skeletal muscle (gracilis muscle) after intravenous administration of practolol (2 mg/kg), a selective myocardial beta receptor blocker which minimized indirect effects of myocardial stimulation on coronary vascular resistance. The left circumflex coronary, cranial tibial, and gracilis arteries were perfused separately but simultaneously at constant flow. Perfusion pressures, left ventricular pressure and dP/dt. and heart rate were recorded. Changes in perfusion pressure to each bed reflected changes in vascular resistance. The direct constrictor effects of sympathetic nerve stimulation, norepinephrine and phenylephrine on coronary vessels were minimal compared with effects on cutaneous and muscular vessels. Subsequent blockade of vascular beta receptors did not augment the constrictor responses. Angiotensin, a nonadrenergic stimulus, produced striking coronary vasoconstriction which exceeded that in skin and approximated that in muscle. These results suggests that there is a paucity of alpha adrenergic receptors in coronary vessels compared to cutaneous and muscular vessels. Direct dilator responses to isoproterenol were similar in coronary and cutaneous vessels, but were greater in muscular vessels. Responses to glyceryl trinitrate, a nonadrenergic dilator, also were greater in skeletal muscle. Therefore, differences in effects of isoproterenol on the three beds may reflect differences in reactivity to dilator stimuli rather than differences in the density of beta receptors. In contrast to norepinephrine, the predominant direct effect of epinephrine on coronary vessels was dilatation mediated through activation of vascular beta receptors. A constrictor effect caused by stimulation of alpha receptors was unmasked by propranolol.Finally, the order of potency of agonists in stimulating coronary vascular beta receptors and the demonstration of selective beta receptor blockade with practolol suggest that beta receptors in coronary vessels resemble those in peripheral vessels more than those in myocardium.