Orekhova I V, Veksler V I
Biull Eksp Biol Med. 1991 Nov;112(11):478-80.
Effects of alpha 1-adrenoagonist phenylephrine (PhE) and lithium, an inhibitor of inositolmonophosphatase, on calcium sensitivity of hyperpermeable rat myocardial fibers were studied. In the presence of propranolol, PhE reduced calcium sensitivity, and this effect was enhanced as calcium concentration was being increased during stimulation with PhE. This appears to relate to an activation of protein kinase C by calcium. LiCl also decreased calcium sensitivity of fibers. This result partially can be explained by a direct effect of Li+ on myofibrils. A combination of PhE and LiCl decreased calcium sensitivity even more, but the effect of PhE in this case was less expressed than in the absence of LiCl. Prasozin, an alpha 1-adrenoblocker, prevented from the effect of PhE both in the presence and in the absence of lithium, thus indicating that stimulation of alpha 1-adrenoceptors was involved in the effects of PhE and lithium observed in this study.
研究了α1 -肾上腺素能激动剂去氧肾上腺素（PhE）和肌醇单磷酸酶抑制剂锂对高通透性大鼠心肌纤维钙敏感性的影响。在普萘洛尔存在的情况下，PhE降低了钙敏感性，并且在用PhE刺激期间随着钙浓度的增加这种作用增强。这似乎与钙激活蛋白激酶C有关。LiCl也降低了纤维的钙敏感性。这一结果部分可以通过Li +对肌原纤维的直接作用来解释。PhE和LiCl的组合进一步降低了钙敏感性，但在这种情况下PhE的作用比不存在LiCl时表现得要小。α1 -肾上腺素能阻滞剂哌唑嗪在有锂和无锂的情况下均能阻止PhE的作用，因此表明α1 -肾上腺素能受体的刺激参与了本研究中观察到的PhE和锂的作用。
