BACKGROUND & AIMS:
:String-shaped reconstituted smooth muscle (SM) fibers were prepared in rectangular wells by thermal gelation of a mixed solution of collagen and cultured SM cells derived from guinea pig stomach. The cells in the fiber exhibited an elongated spindle shape and were aligned along the long axis. The fiber contracted in response to KCl (140 mM), norepinephrine (NE; 10(-7) M), epinephrine (10(-7) M), phenylephrine (10(-6) M), serotonin (10(-6) M), and histamine (10(-5) M), but not acetylcholine (10(-5) M). Phentolamine (10(-7) M) produced a parallel rightward shift of the NE dose-response curve. Moreover, NE-induced contraction was partially inhibited by nifedipine and completely abolished by the intracellular Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester, the myosin light chain kinase inhibitor ML-9, the Rho kinase inhibitor Y-27632, and papaverine. A [(3)H]quinuclidinyl benzilate binding study revealed that the loss of response to acetylcholine was due to the loss of muscarinic receptor expression during culture. The expression of contractile proteins in the fibers was similar to that in cultured SM cells. These results suggest that, although the fiber is not a model for fully differentiated SM, contractile mechanisms are maintained.
背景与目标:
: 通过将源自豚鼠胃的胶原蛋白和培养的SM细胞的混合溶液热凝胶化,在矩形孔中制备了线状重构的平滑肌 (SM) 纤维。纤维中的细胞呈细长的纺锤形,并沿长轴对齐。纤维收缩响应KCl (140 mM),去甲肾上腺素 (NE; 10(-7) M),肾上腺素 (10(-7) M),去氧肾上腺素 (10(-6) M),5-羟色胺 (10(-6) M),和组胺 (10(-5) M),但不是乙酰胆碱 (10(-5) M)。酚妥拉明 (10(-7) M) 产生了NE剂量-反应曲线的平行右移。此外,NE诱导的收缩被硝苯地平部分抑制,并被细胞内Ca(2 +) 螯合剂1,2-双 (2-氨基苯氧基) 乙烷-N,N,N',N'-四乙酸乙酰氧基甲酯完全消除,肌球蛋白轻链激酶抑制剂ML-9,Rho激酶抑制剂Y-27632,和罂粟碱。A [(3)H] 奎宁环烷基苯甲酸酯结合研究表明,对乙酰胆碱反应的丧失是由于培养过程中毒蕈碱受体表达的丧失。纤维中收缩蛋白的表达与培养的SM细胞相似。这些结果表明,尽管纤维不是完全分化SM的模型,但仍保持收缩机制。