Determination of synaptic phenotype: insulin and cAMP independently initiate development of electrotonic coupling between cultured sympathetic neurons.
Determination of synaptic phenotype: insulin and cAMP independently initiate development of electrotonic coupling between cultured sympathetic neurons.
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突触表型的测定：胰岛素和cAMP独立地启动培养的交感神经元之间电紧张耦合的发展。
DOI：
10.1073/pnas.81.19.6235
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发表时间：
1984
影响因子：
11.1
通讯作者：
Bennett,MV
中科院分区：
文献类型：
--
作者：
Kessler,JA;Spray,DC;Saez,JC;Bennett,MV
当细胞在加血清的营养培养基中培养2周时，从新生大鼠颈上神经节分离的成对交感神经元之间的电紧张耦合很少见，而当细胞在无血清成分确定的培养基中培养相同时间时，这种耦合很常见。这种确定成分培养基是相同的营养培养基，但添加了五种因子（黄体酮、转铁蛋白、腐胺、胰岛素和硒）。当单独添加到含血清培养基中时，胰岛素和较小程度的硒促进电渗和染料偶联的发展。剂量低至 0.01 微克/毫升即可产生胰岛素效应，并在暴露 3 至 5 天后达到最大效果。细胞暴露于二丁酰 cAMP 也会增强电紧张耦合的发生率。这种效果用低至 0.1 mM 的剂量即可获得，速度更快（约等于暴露 12 小时时达到最大），并且在磷酸二酯酶抑制剂咖啡因存在的情况下延长。丁酸盐本身在小程度上促进偶联，但其他膜渗透类似物的类似作用证实了 cAMP 的参与。在特定培养基中生长的培养物中，cAMP 的内源水平显着升高，但在添加了胰岛素或硒的含血清培养基中则没有显着升高。我们得出结论，cAMP 和胰岛素或硒对偶联的促进作用是独立的。因此，确定培养基中偶联的发展似乎是添加促进物质（胰岛素、硒）和消除血清对 cAMP 水平的抑制作用的结果。
Electrotonic coupling between pairs of sympathetic neurons dissociated from superior cervical ganglia of neonatal rats is rare when cells are cultured for 2 weeks in a nutrient medium plus serum and is common when cells are cultured for the same period in serum-free defined medium. This defined medium is the same nutrient medium with five added factors (progesterone, transferrin, putrescine, insulin, and selenium). When added singly to serum-containing medium, insulin and, to a lesser extent, selenium promote the development of electrotonic and dye coupling. The insulin effect is obtained with doses as low as 0.01 microgram/ml and is maximal after exposures from 3 to 5 days. The incidence of electrotonic coupling is also enhanced by exposure of cells to dibutyryl cAMP. This effect is obtained with doses as low as 0.1 mM, is faster (being maximal at approximately equal to 12 hr exposure), and is prolonged in the presence of the phosphodiesterase inhibitor caffeine. Butyrate itself promotes coupling to a small extent, but cAMP involvement is confirmed by similar effects of other membrane permeant analogues. Endogenous levels of cAMP are significantly elevated in cultures grown in the defined medium but not in those in serum-containing medium to which insulin or selenium are added. We conclude that the promotion of coupling by cAMP and by insulin or selenium are independent. The development of coupling in the defined medium thus seems to be a consequence of the addition of promoting substances (insulin, selenium) and the removal of an inhibitory effect of serum on cAMP levels.