Neurite development in vitro: II. The role of microfilaments and microtubules in dibutyryl adenosine 3′,5′-cyclic monophosphate and nerve growth factor stimulated maturation

Dibutyryl cyclic AMP (DBC) and Nerve Growth Factor (NGF) have both been shown to enhance in vitro neuronal maturation in embryonic sensory ganglia. Since microfilaments and microtubules are known to be involved in neurite elongation, embryonic chick dorsal root ganglia have been treated with cytochalasin B and colcemid in the presence of these growth promoters (DBC or NGF). Established 48-hr cultures show drastic neurite retraction when treated with either inhibitor. The treatment of cultures with DBC or NGF in the presence of colcemid reverses the inhibitive effects and normal elongation occurs. The growth stimulators, however, are unable to effectively reverse the action of cytochalasin B. These data suggest that increased microtubule assembly is involved in DBC and NGF stimulation of neurite elongation, and hence provide further support for the suggestion that cyclic AMP mediates some of the actions of NGF.