THE EFFECT OF NERVE GROWTH-FACTOR ON CHOLINERGIC CELLS IN PRIMARY FETAL STRIATAL CULTURES - CHARACTERIZATION BY IN-SITU HYBRIDIZATION

In situ hybridization using S-35-labeled antisense oligonucleotide pro bes for choline acetyltransferase (ChAT), and ml and m2 muscarinic rec eptors was employed to monitor the effect of nerve growth factor (NGF) on cholinergic cells in mixed neuronal-glial striatal brain cultures prepared from E16/E17 rat embryos. In cultures treated with NGF, cells reactive to the ChAT oligonucleotide probe were significantly larger than cells in untreated cultures. In addition, there was a significant increase in the number of silver grains over reactive cells in cultur es exposed for 9-10 days to exogneous NGF. Similar results were obtain ed with an oligonucleotide probe specific for m2 muscarinic receptors: in NGF-treated cultures, cells reactive to the m2 receptor probe were significantly larger and had more silver grains than cells from non-t reated cultures. On the other hand, no significant effect of NGF on ce ll size or on the number of grains was observed for cells reactive to an ml muscarinic receptor probe. These results demonstrate that NGF sp ecifically increases the transcription of genes (ChAT and m2 muscarini c receptor) the expression of which is associated with cholinergic neu rons, promoting the growth of this particular type of neuron.