Gambassi G, Capogrossi M C
Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD.
Cardiologia. 1992 Aug;37(8):565-7.
Two different myocardial alpha 1-adrenergic receptor subtypes have been recently described. Since their functional role is still unknown we examined the effect of alpha 1A and alpha 1B on contractile properties, cell Ca2+ homeostasis and myofilament sensitivity to Ca2+ in indo-1 loaded ventricular myocytes. Non selective alpha 1-adrenergic stimulation increases twitch amplitude, systolic Ca2+ and myofilament sensitivity. Same effects but amplified are associated with alpha 1A-receptors stimulation. In contrast, alpha 1B-receptors stimulation decreases twitch amplitude and systolic Ca2+ below control value. Myocardial alpha 1-adrenergic stimulation results from the opposite actions of the 2 subtypes.
最近已描述了两种不同的心肌α1 - 肾上腺素能受体亚型。由于它们的功能作用仍不清楚，我们研究了α1A和α1B对indo - 1负载的心室肌细胞收缩特性、细胞钙稳态和肌丝对钙敏感性的影响。非选择性α1 - 肾上腺素能刺激可增加收缩幅度、收缩期钙和肌丝敏感性。与α1A受体刺激相关的是相同但增强的效应。相比之下，α1B受体刺激可使收缩幅度和收缩期钙低于对照值。心肌α1 - 肾上腺素能刺激源于这两种亚型的相反作用。
