SELECTIVE DEGENERATION OF CA1 PYRAMIDAL CELLS BY CHRONIC APPLICATION OF BISMUTH

The heavy metal bismuth induces a new type of selective neuronal degen eration that shares some common aspects with that seen following hypox ia and ischemia. Continuous application of 3 mu m bismuth to organotyp ic cultures of rat hippocampus resulted after 2-3 weeks in selective d egeneration of CA1 pyramidal cells, while CA3 pyramidal cells, dentate granule cells, and subicular neurons were resistant. With 10 mu m bis muth, the majority of hippocampal neurons degenerated. The addition of 20 mu m MK-801, a noncompetitive NMDA-antagonist, during the entire c ulturing period failed to prevent neuronal degeneration induced by 3 m u m bismuth. GABA-immunoreactive interneurons were also affected by bi smuth, but were generally less sensitive than CA1 pyramidal cells. Acu te application of up to 100 mu m bismuth did not change the electrophy siological properties of CA1 pyramidal cells. (C) 1994 Wiley-Liss, Inc .