Meyer W, Böhm M, Herzig J W, Mügge A, Schmitz W, Scholz H
Abteilung Allgemeine Pharmakologie, Universitäts-Krankenhaus Eppendorf, Universität Hamburg, Fed. Rep. of Germany.
Arzneimittelforschung. 1993 Apr;43(4):432-5.
The effects of the alpha 1-adrenoceptor agonist phenylephrine (CAS 59-42-7) on Ca++ sensitivity of the contractile proteins and on force of contraction of the heart were studied in right ventricular preparations isolated from pigs. In contracting trabeculae phenylephrine (3-100 mumol/l) increased force of contraction in the presence of propranolol maximally by 91.8 +/- 36.2% (n = 5). The effect of phenylephrine was antagonized by prazosin, indicating an alpha-adrenoceptor-mediated positive inotropic effect. Glycerol- and Lubrol WX-extracted trabeculae ("chemically skinned") were activated by Ca(++)-concentrations between 0.01 and 47.7 mumol/l. Phenylephrine (0.1-100 mumol/l) did not affect the Ca++ activated force in these preparations. A direct intracellular action of phenylephrine on contractile proteins is thus rather unlikely to contribute to the positive inotropic effect of phenylephrine.
在从猪分离出的右心室标本中，研究了α1 -肾上腺素能受体激动剂去氧肾上腺素（化学物质登记号59 - 42 - 7）对收缩蛋白的钙离子敏感性以及心脏收缩力的影响。在收缩的小梁中，去氧肾上腺素（3 - 100 μmol/L）在普萘洛尔存在的情况下使收缩力最大增加91.8±36.2%（n = 5）。去氧肾上腺素的作用被哌唑嗪拮抗，表明存在α -肾上腺素能受体介导的正性肌力作用。甘油和十二烷基聚氧乙烯醚WX提取的小梁（“化学去膜”）由0.01至47.7 μmol/L的钙离子浓度激活。去氧肾上腺素（0.1 - 100 μmol/L）在这些标本中不影响钙离子激活的力量。因此，去氧肾上腺素对收缩蛋白的直接细胞内作用不太可能是其正性肌力作用的原因。
