Modulation by the thyroid state of intracellular calcium and contractility in ferret ventricular muscle.
Modulation by the thyroid state of intracellular calcium and contractility in ferret ventricular muscle.
复制标题
甲状腺状态对细胞内钙和雪貂心室肌收缩力的调节。
DOI：
10.1161/01.res.63.6.1080
复制
发表时间：
1988
影响因子：
20.1
通讯作者：
Morgan,JP
中科院分区：
文献类型：
--
作者：
MacKinnon,R;Gwathmey,JK;Allen,PD;Briggs,GM;Morgan,JP
本研究的目的是确定甲状腺功能亢进或甲状腺功能减退引起的心脏收缩异常是否是由细胞内Ca 2+处理的变化或心室肌球蛋白同工酶分布的改变引起的。从甲状腺功能正常的雪貂和用L-甲状腺素（甲状腺功能亢进）或甲巯咪唑（甲状腺功能减退）治疗的雪貂获得的右心室乳头肌装载有钙指示剂水母发光蛋白，用于记录等长收缩期间细胞内Ca 2+水平。在甲状腺功能减退雪貂的肌肉中，与对照组相比，峰值张力降低，收缩持续时间延长;这些变化与幅度降低和持续时间延长的Ca 2+瞬变相关。甲状腺功能亢进症在Ca 2+瞬变和相关等长收缩的时间过程中产生了相反的变化。天然聚丙烯酰胺凝胶电泳进行肌球蛋白提取的右心室游离壁的控制和治疗雪貂。甲状腺功能亢进状态与新的肌球蛋白形成有关，如焦磷酸盐凝胶上出现三条肌球蛋白带所示。甲状腺功能减退和甲状腺功能正常雪貂的肌球蛋白凝胶显示出一条带，与甲状腺功能亢进雪貂的三条带中最慢的一条带一起迁移。这些结果表明，在这两个Ca 2+处理和肌球蛋白同工酶的变化可能有助于在甲状腺功能亢进症中观察到的收缩异常。细胞内Ca 2+处理的改变可能是甲状腺功能减退引起的收缩变化的原因。
The purpose of this study was to determine whether the cardiac contractile abnormalities induced by hyperthyroidism or hypothyroidism are caused by changes in intracellular Ca2+ handling or by alterations in the distribution of isoenzymes of ventricular myosin. Right ventricular papillary muscles obtained from euthyroid ferrets and ferrets treated with L-thyroxine (hyperthyroid) or methimazole (hypothyroid) were loaded with the calcium indicator aequorin for recording intracellular Ca2+ levels during isometric contraction. In muscles from the hypothyroid ferrets, peak tension was reduced and the duration of contraction prolonged compared to the controls; these changes were associated with a Ca2+ transient of decreased amplitude and prolonged duration. Hyperthyroidism produced opposite changes in the time course of the Ca2+ transient and the associated isometric contraction. Native polyacrylamide gel electrophoresis was performed on myosin extracted from the right ventricular free wall of control and treated ferrets. The hyperthyroid state was associated with new myosin formation as indicated by the appearance of three myosin bands on the pyrophosphate gel. Gels of myosin from hypothyroid and euthyroid ferrets showed a single band that migrated with the slowest of the three bands from the hyperthyroid ferrets. These results suggest that changes in both Ca2+ handling and myosin isoenzymes may contribute to the contractile abnormalities observed in hyperthyroidism. Alterations in intracellular Ca2+ handling alone may account for the contractile changes induced by hypothyroidism.