Retinoic acid treatment enhances the acetylcholine contents in the human teratocarcinoma cell line NTera-2

Human NTera-2/clone D1 teratocarcinoma cells are induced by retinoic acid ( RA) to differentiate into postmitotic cells with morphological and biochemi cal characteristics of embryonic human neurones. Currently only limited inf ormation concerning peptide-contents and neurotransmitter pools of these ce lls is available. Zeller and Strauss [Int. J. Dev. Neurosci. 1995;13(5):437 ] described an increase in choline acetyltransferase (ChAT) activity in RA- treated, but not in untreated NTera-2 cells, suggesting the induction of a cholinergic phenotype during treatment with RA. In the present study we inv estigated the effect of RA-differentiation on the amount of the neurotransm itters acetylcholine (ACh), and dopamine in NTera-2 in order to specify the transmitter phenotype induced by RA-differentiation. We found that a 4-wee k treatment of NTera-2 cells with 10 muM RA markedly increased the ACh-cont ent of these cells, while dopamine levels were unchanged. Depolarisation wi th potassium (60 mM) enhanced ACh-outflow in the differentiated cells in a Ca++ dependent way. Also neuropeptides like substance P and NPY were detect able in the undifferentiated NTera-2 cells, while vasointestinal peptide (V IP) could not be found in either precursor or RA-differentiated cells. Diff erentiation was accompanied by a marked reduction of neutral endopeptidase enzyme activity and aminopeptidase activity. From these observations it was concluded that RA induces a cholinergic neurochemical differentiation of t his human teratocarcinoma cell line, and that these cells might provide a m odel system to investigate cholinergic properties of human origin. (C) 2000 Elsevier Science B.V. All rights reserved.