Norepinephrine-induced calcium signaling and expression of adrenoceptors in avian tendon cells.
Norepinephrine-induced calcium signaling and expression of adrenoceptors in avian tendon cells.
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DOI：
10.1152/ajpcell.00099.2004
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发表时间：
2004-10
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影响因子：
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通讯作者：
M. Wall;J. Faber;Xi Yang;M. Tsuzaki;A. Banes
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文献类型：
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作者：
M. Wall;J. Faber;Xi Yang;M. Tsuzaki;A. Banes
交感传出神经存在于肌腱中，但它们在肌腱中的功能尚不清楚。α（1）-肾上腺素受体由多种细胞类型表达。在去甲肾上腺素（NE）存在下，肾上腺素受体激活G（q/11）信号通路，随后增加细胞内Ca（2+）浓度（[Ca（2+）]（ic））。假设鸟类肌腱细胞表达功能性肾上腺素受体，通过增加[Ca（2+）]（ic）对NE做出反应。通过RT-PCR分析禽腱细胞的α（1）-肾上腺素受体的mRNA表达。禽腱表达α（1A）-和α（1B）-肾上腺素受体亚型。此外，肌腱表面腱外膜细胞和内部成纤维细胞注入Ca（2+）敏感染料fura 2，并刺激NE通过增加[Ca（2+）]（ic）。α（1A）-肾上腺素能受体拮抗剂KMD-3213显著降低Ca（2+）反应。其它肾上腺素受体拮抗剂对Ca（2+）反应无影响。细胞外Ca（2+）的缺乏也显著降低了对NE的反应，表明Ca（2+）内流有助于[Ca（2+）]（ic）的升高。本研究首次证明了腱细胞表达肾上腺素受体，NE诱导的Ca（2+）反应与α（1A）-肾上腺素受体亚型偶联。
Sympathetic efferent nerves are present in tendons, but their function within tendon is unknown. alpha(1)-Adrenoceptors are expressed by a variety of cell types. In the presence of norepinephrine (NE), adrenoceptors activate G(q/11) signaling pathways that subsequently increase intracellular Ca(2+) concentration ([Ca(2+)](ic)). It was hypothesized that avian tendon cells express functional adrenoceptors that respond to NE by increasing [Ca(2+)](ic). Avian tendon cells were analyzed for mRNA expression of alpha(1)-adrenoceptors by RT-PCR. Avian tendons expressed the alpha(1A)- and alpha(1B)-adrenoceptor subtypes. Furthermore, both tendon surface epitenon cells and internal fibroblasts infused with a Ca(2+)-sensitive dye, fura 2, and stimulated with NE responded by increasing [Ca(2+)](ic). KMD-3213, an alpha(1A)-adrenoceptor antagonist, significantly reduced the Ca(2+) response. Other adrenoceptor antagonists had no effect on the Ca(2+) response. The absence of extracellular Ca(2+) also significantly reduced the response to NE, indicating that Ca(2+) influx contributed to the rise in [Ca(2+)](ic). This study provides the first evidence that tendon cells express adrenoceptors and that the NE-induced Ca(2+) response is coupled to the alpha(1A)-adrenoceptor subtype.