THE ONTOGENY OF NADPH-DIAPHORASE NEURONS IN SERUM-FREE STRIATAL CULTURES PARALLELS IN-VIVO DEVELOPMENT

Nitric oxide synthase is co-localized with somatostatin and neuropepti de Y in a subpopulation of striatal interneurons that stain selectivel y for NADPH-diaphorase. We studied the ontogeny of diaphorase-positive neurons in striatal serum-free cultures derived from 15-16-day-old CD 1 mice. NADPH-diaphorase staining was detected as early as embryologic al day 18 in vivo and day 5 in vitro. Over the next seven days the num ber of neurons staining for NADPH-diaphorase increased rapidly and the n levelled off at about 0.5-1% of the total neuronal population both i n vivo and in vitro. The cultured diaphorase neurons were also similar to their in vivo counterparts in terms of morphology and dendritic br anching. Striatal neurons expressing NADPH-diaphorase exhibit similar ontogeny, morphology and neurochemical characteristics in vivo and in serum-free primary neuronal cultures. The culture system may represent a useful model for studying this important subgroup of striatal neuro ns.