Effect of ferric nitrilotriacetate on rostral mesencephalic cells

After murine fetal cells from the rostral mesencephalic tegmentum were isolated, prepared, and cultured; neuronal and glial cells in primary mixed cell cultures were exposed to ferric nitrilotriacetate (Fe-NTA) at varying concentrations. Studies were performed at 23 days in culture after 14 day exposure to Fe-NTA. In addition to morphologic studies, biochemical assays including specific ³H]flunitrazepam (FLU) binding, clonazepam (CLO)-displaceable ³H]-FLU binding, Ro5-4864-displaceable ³H]-FLU binding, ³H]dopamine (DA) uptake, ³H]haloperidol (HAL) binding, ³H]spiperone (SP) binding, glutamine synthetase activity (GS), and protein determinations were performed. The data demonstrate that chelated ferric iron has an adverse effect on these cells. The data also demonstrate that increasing concentrations of Fe-NTA resulted in massive neuronal dropout leaving the culture population virtually all glial; however, the specific binding of ³H]HAL and ³H]SP increased. There was a concomitant decrease in both glutamine synthetase activity and overall protein content. The mechanism of enhancement in the presence of Fe-NTA of ³H]HAL and ³H]SP binding is unknown and may be unique, but may be related to the known increase in D₂ receptor ligand affinity in the presence of other multivalent cations (Ca²⁺ and Mg²⁺).