Amerini S, Fusi F, Piazzesi G, Mantelli L, Ledda F, Mugelli A
Dev Pharmacol Ther. 1985;8(1):34-42. doi: 10.1159/000457019.
The positive inotropic effect of phenylephrine (in the presence of atenolol) and isoprenaline was studied in isolated right ventricular strips obtained from Wistar rats aged 2 weeks, 3 months, and 26 months. The positive inotropic effects induced by phenylephrine and isoprenaline were higher in the 2-week-old than in the 3- or 26-month-old rats. The typical 'alpha-type' or 'beta-type' responses were induced by phenylephrine (plus atenolol) or isoprenaline, in all the age groups. The EC50 values for the alpha-mediated positive inotropic effect decreased with age, while the EC50 value for the positive inotropic effect of isoprenaline increased in the senescent heart. These results suggest an enhanced alpha-adrenergic sensitivity in the senescent heart.
研究了去氧肾上腺素（在阿替洛尔存在的情况下）和异丙肾上腺素对从2周龄、3月龄和26月龄Wistar大鼠分离得到的右心室肌条的正性肌力作用。去氧肾上腺素和异丙肾上腺素诱导的正性肌力作用在2周龄大鼠中比在3月龄或26月龄大鼠中更强。在所有年龄组中，去氧肾上腺素（加阿替洛尔）或异丙肾上腺素均诱导出典型的“α型”或“β型”反应。α介导的正性肌力作用的半数有效浓度（EC50）值随年龄降低，而异丙肾上腺素正性肌力作用的EC50值在衰老心脏中升高。这些结果表明衰老心脏中α-肾上腺素能敏感性增强。
