ST14A cells have properties of a medium-size spiny neuron

The ST14A cell line was previously derived from embryonic day 14 rat striat al primordia by retroviral transduction of the temperature-sensitive SV40 l arge T antigen. We showed that cell division and expression of nestin persi sts at 33 degreesC, the permissive temperature, whereas cell division cease s, nestin expression decreases, and MAP2 expression increases at the nonper missive temperature of 39 degreesC. In this study, we further characterized the cells and found that they express other general and subtype-specific n euronal characteristics, ST14A cells express enolase and beta III-tubulin, Furthermore, they express the striatal marker DARPP-32, which is up-regulat ed upon differentiation of the cells by growth in serum-free medium. Stimul ation with dopamine, the DB-dopamine receptor agonist quinpirole, or the D1 -dopamine receptor agonist SKF82958 results in phosphorylation of CREB. Tre atment of the cells with a mixture of reagents which stimulate the MAPK and adenylyl cyclase pathways radically changes the morphology of the ST14A ce lls. The cells develop numerous neurite-like appearing processes which stai n with beta III-tubulin. Moreover, under these conditions, intracellular in jection of rectangular depolarizing current stimuli elicits overshooting ac tion potentials with a relatively fast depolarization rate when starting fr om a strongly hyperpolarized membrane potential. Taken together, these data imply that the ST14A cell line displays some of the characteristics of a m edium-size spiny neuron subtype and provides a new tool to elucidate the pa thways and molecules involved in medium-size spiny neuron differentiation a nd disease. (C) 2000 Academic Press.