QUANTITATIVE-ANALYSIS OF GAP-43 EXPRESSION BY NEURONS IN MICROCULTURES USING CELL-ELISA

A cell-ELISA technique is described which allows the quantification of GAP-43 protein in a large number of microcultures of adult dorsal roo t ganglion neurons. GAP-43 is measured in the 1-10 ng range, correspon ding to the amount of GAP-43 present in fewer than 500 DRG neurons. Sp ecificity of the assay is confirmed using Western blotting and immunoc ytochemistry. The GAP-43 content of adult DRG microcultures rises duri ng 2 weeks in culture, although the number of surviving neurons decrea ses. The GAP-43 content of cultured adult DRG neurons is not increased by chronic exposure to added nerve growth factor after 7 days in vitr o. However, GAP-43 is increased in DRG taken from animals with prior p eripheral nerve injury, and is decreased by chronic exposure to dibuty ryl cyclic AMP after 7 days in vitro. The method affords the sensitivi ty and statistical power to document modest changes in GAP-43 protein abundance in complex cultures. (C) 1997 Elsevier Science B.V.