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Development of Sodium Channel Protein During Chemically Induced Differentiation of Neuroblastoma Cells
Author(s) -
Baumgold Jesse,
Spector Ilan
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb05656.x
Subject(s) - saxitoxin , sodium channel , scorpion toxin , batrachotoxin , sodium , toxin , microbiology and biotechnology , biology , tetrodotoxin , biochemistry , chemistry , biophysics , organic chemistry
We have previously shown that the [ 3 H]saxitoxin binding site of the sodium channel is expressed independently of the [ 125 I]scorpion toxin binding site in chick muscle cultures and in rat brain. In the present work, we studied the development of the sodium channel protein during chemically induced differentiation of N1E‐115 neuroblastoma cells, using [ 3 H]saxitoxin binding, [ 125 I]scorpion toxin binding, and 22 Na uptake techniques. When grown in their normal culture medium, these cells are mostly undifferen‐tiated, bind 90 ± 10 fmol of [ 3 H]saxitoxin/mg of protein and 112 ± 14 fmol of [ 125 I]scorpion toxin/mg protein, and, when stimulated with scorpion toxin and batrachotoxin, take up 70 ± 5 nmol of 22 Na/min/mg of protein. Cells treated with dimethyl sulfoxide (DMSO) or hexamethy‐lene‐bis‐acetamide (HMBA) differentiate morphologically within 3 days. At this time, the [ 3 H]saxitoxin binding, the [ 125 I]scorpion toxin binding, and the 22 Na uptake values are not very different from those of undifferentiated cells. With subsequent time in DMSO or HMBA, these values continue to increase, a result indicating that the main period of sodium channel expression occurs well after the cells have assumed the morphologically differentiated state. The data indicate that the expression of sodium channels and morphological differentiation are independently regulated neuronal properties, that the attainment of morphological differentiation is necessary but not in itself sufficient for full expression of the sodium channel proteins, and that, in contrast to the chick muscle cultures and rat brain, the [ 3 H]saxitoxin site and [ 125 I]scorpion toxin site appear to be coregulated in N1E‐115 cells.