Effects of chronic @entity109 exposure on cultured XXXX spinal cord neurons.

@entity19 @entity17166 @entity1 @entity109
The anticonvulsant @entity109 (PB), at concentrations of 20, 40, and 90 micrograms/ml, was chronically applied to cell cultures of @entity19 spinal cord from day 2 or day 14 after initial plating, and the effects of this exposure on neuronal density and morphological characteristics were determined. Neuronal morphological characteristics were analyzed quantitatively following intracellular injection of the fluorescent dye Lucifer yellow. Cultures exposed to PB for 6 weeks, from day 14 after plating, showed concentration-dependent reductions in neuronal density; both large and small neurons were equally affected. PB exposure also reduced dendritic branching frequency, and the length of dendrites, of remaining large neurons. A higher percentage of these neurons had a bipolar branching pattern than was normally the case. Neurons in cultures exposed to PB from day 2 after plating, compared with those exposed from day 14, showed significantly less alteration in terms of density and morphological characteristics. Effects on neuronal morphological characteristics increased with duration of drug exposure. Equimolar concentrations of @entity17166 produced effects similar to those produced by PB. Chronic exposure to PB adversely affects survival and morphological characteristics of @entity1 central neurons grown in cell culture. Curiously, exposure from the time of initial plating appears to be less deleterious than exposure initiated 2 weeks later. To the extent that neuronal development in vitro can be compared to the situation in vivo, these results, and those of other investigators, raise concerns about long-term exposure of the developing @entity1 nervous system to PB.
