A neural influence on the appearance of sodium current in Xenopus embryonic myocytes.
Regulation of early embryonic expression of sodium current in cultured Xenopus laevis myocytes was investigated. In myocytes isolated before innervation and cultured for about 1 day, only 51% expressed sodium current at a mean density of 74 +/- 20 pA/pF (mean +/- SEM; n = 26), inadequately reflecting the functional development of skeletal muscle in vivo at this time. This cell-autonomous expression pattern could be modulated. First, co-culture of myocytes and dissociated neural tissue induced additional sodium current expression (82%; 172 +/- 31 pA/pF, n = 14) and, secondly, removal of calcium from the culture medium reduced sodium current density (13 +/- 6 pA/pF; n = 5). The former results suggest that a diffusible factor released from differentiating neurons is able to initiate the expression of sodium channels in myocytes.
Prabhakar
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E
Department of Pharmacology, Medical School, University of Birmingham, Edgbaston, UK.
Barnes
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T
Spruce
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AE
D000818:Animals; D002478:Cells, Cultured / Q000502:physiology; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000254:growth & development*; D009474:Neurons / Q000502:physiology*; D015222:Sodium Channels / Q000502:physiology*; D014981:Xenopus
D015222:Sodium Channels