TTFFLUOR DRGs are Green fluorescent primary DRG cells, which has been developed through transient transfection with tGFP expression vector expressing the green fluorescent protein gene sequences as free cytoplasmatic protein. Within 2-3 days in culture, the fluorescent DRG neurons display extensive neurite outgrowth. On day 10 approximately they show the same size and neurochemical type distribution as freshly dissociated rat DRG neurons. This is consistent with the generally accepted view that after 9 days in culture, DRG neurons are physiologically mature.