Positive inotropic effects of methoxamine: evidence for alpha-adrenergic receptors in ventricular myocardium.
Positive inotropic effects of methoxamine: evidence for alpha-adrenergic receptors in ventricular myocardium.
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甲氧明的正性肌力作用：心室心肌中α-肾上腺素能受体的证据。
DOI：
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发表时间：
1975
影响因子：
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通讯作者：
W. Parmley
中科院分区：
文献类型：
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作者：
B. Rabinowitz;L. Chuck;M. Kligerman;W. Parmley
本研究观察了甲氧胺对猫心室肌细胞力形成和腺苷酸环化酶活性的影响。甲氧胺产生了剂量相关的增加力量发展的等距收缩猫乳头肌。甲氧胺的正性肌力作用不改变β-肾上腺素能阻滞剂（普萘洛尔），或前利血平的儿茶酚胺耗竭，但完全阻止了α-肾上腺素能阻滞剂（酚妥拉明或麦角胺）。麦角胺、酚妥拉明和甲氧胺对腺苷酸环化酶活性均无直接影响。酚妥拉明没有减弱成对电刺激产生的力量发展的增加，这表明它不会阻止钙进入肌肉。总之，甲氧胺使猫乳头肌的力量发展产生剂量相关性增加，这被心室肌中的α-肾上腺素能受体选择性阻断。
The present study was undertaken to evaluate the effects of methoxamine on force development and adenyl cyclase activity in cat ventricular myocardium. Methoxamine produced a dose-related increase in force development of isometrically contracting cat papillary muscles. The positive inotropic effects of methoxamine were not altered by beta-adrenergic blockade (propranolol), or catecholamine depletion by prior reserpinization, but were completely prevented by alpha-adrenergic blockade (phentolamine or ergotamine). Neither ergotamine, phentolamine, nor methoxamine had any direct effects on adenyl cyclase activity. Phentolamine did not attenuate the increase in force development produced by paired electrical stimulation, suggesting that it does not block the entry of calcium into the muscle. In summary, methoxamine produced a dose-related increase in force development of the cat papillary muscle that was selectively blocked by alpha-adrenergic receptors in ventricular myocardium.