Failure of 6-aminonicotinamide in selectively damaging astrocytes in vitro

The present study investigates cytotoxic effects of 6-amino-nicotinamide (6-AN), a nicotinamide antagonist, in primary cultures of the dissociated postnatal mouse cerebellum. Initial effects were seen with 1.5 microM 6-AN of this substance included in the culture medium at plating. Established cultures responded to concentrations higher than 3.1 microM. The relative number of astrocytes (identified immunohistochemically) was not reduced in cultures exposed to low, but effective concentrations of 6-AN. We therefore conclude that 6-AN is no suitable agent to regulate the number of astrocytes in cell cultures. Thus, at the present alpha-aminoadipic acid remains the only substance which can be considered a selective gliotoxin in vivo and in vitro.