Quik M, Philie J, Goldstein G
Department of Pharmacology, McGill University, Montreal, Que., Canada.
Brain Res. 1992 Dec 18;599(1):117-28. doi: 10.1016/0006-8993(92)90858-7.
Thymopoietin, a polypeptide hormone isolated from thymus and involved in immune function, potently inhibited [125I]alpha-bungarotoxin binding to neonatal muscle cells in culture (IC50 = 3.8 nM) and blocked carbachol-stimulated 22Na uptake with an IC50 of 1.9 +/- 0.2 nM and 23 +/- 7 nM at a half-maximal and maximal concentration of carbachol, respectively. Studies were subsequently done to evaluate potential long-term functional consequences of this interaction of thymopoietin at the nicotinic receptor. Exposure (1-3 days) of neonatal muscle cells in culture to nicotine (3 x 10(-6) M) or carbachol (1 x 10(-6) M) resulted in a decline in myotube branching and a decrease in myotube length. Thymopoietin did not appreciably alter myotube morphology on its own; however, it prevented the effects of nicotine and carbachol on muscle cell morphology at concentrations (1-10 nM) which corresponded well to those with which thymopoietin interacted at the receptor. The action of alpha-bungarotoxin on the myotubes was very similar to that of thymopoietin. These studies suggest that the endogenously occurring polypeptide, thymopoietin, has the potential to modulate muscle cell morphology through an interaction at the nicotinic receptor.
胸腺生成素是一种从胸腺中分离出来且参与免疫功能的多肽激素，它能有效抑制培养的新生肌肉细胞与[125I]α-银环蛇毒素的结合（IC50 = 3.8 nM），并阻断卡巴胆碱刺激的22Na摄取，在卡巴胆碱半最大浓度和最大浓度时，IC50分别为1.9±0.2 nM和23±7 nM。随后进行了研究，以评估胸腺生成素与烟碱样受体相互作用的潜在长期功能后果。将培养的新生肌肉细胞暴露于尼古丁（3×10−6 M）或卡巴胆碱（1×10−6 M）1 - 3天，会导致肌管分支减少和肌管长度缩短。胸腺生成素自身不会明显改变肌管形态；然而，在与胸腺生成素在受体处相互作用的浓度（1 - 10 nM）下，它能阻止尼古丁和卡巴胆碱对肌肉细胞形态的影响。α-银环蛇毒素对肌管的作用与胸腺生成素非常相似。这些研究表明，内源性多肽胸腺生成素有可能通过与烟碱样受体相互作用来调节肌肉细胞形态。
