Studies on cultured rat Schwann cells. II. Comparison with a rat Schwann cell line.

Cultured rat Schwann cells do not exhibit the ring-like changes in cell shape previously reported to be induced in the Schwann cell line RN22 by elevation of intracellular cyclic AMP. They do, however, undergo different shape changes on treatment with cholera toxin or low serum concentration. Furthermore, DNA synthesis in the cell line is inhibited by treatment with cholera toxin and unaffected by bovine pituitary extract, though both of these agents stimulate DNA synthesis in normal Schwann cells. Our results, therefore, do not support the hypothesis that elevation of intracellular cyclic AMP is a positive signal for myelination by the Schwann cell. Moreover, they illustrate the need for caution in drawing conclusions about normal cells of the nervous system from studies on neural cell lines.