Progressive accumulation of large aggregates of calcium-containing polysaccharides and basophilic debris within specific thalamic nuclei after lithium/pilocarpine-induced seizures.
Between 30 and 50 days after the induction of seizures by a single injection of lithium and pilocarpine, large aggregates of Nissl-staining material appeared; they occupied up to 35% of the thalamic volume. Both histochemical and atomic absorption analyses indicated elevated concentrations of Ca++ (and possibly Mg++) within this substance that was also composed of polysaccharides and nucleic acids. Significant interactions between time since seizure induction and form of the material indicated a progressive accretion of this material from diffusely scattered micrometer granules to large crystalline forms. We suggest this material is composed of endoplasmic reticular debris that is bound by bivalent cations; because the severity of damage exceeds local phagocytic capacity, the material aggregates and then crystallizes. Possible relation to thalamic calcification in neonatal ischemic brains is considered.
Lafreniere
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GF
Behavioral Neuroscience Laboratory, Laurentian University, Sudbury, Ontario.
Peredery
O
O
Persinger
M A
MA
D000818:Animals; D001491:Basophils / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D006651:Histocytochemistry; D008094:Lithium; D008297:Male; D010862:Pilocarpine; D011134:Polysaccharides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism*; D013054:Spectrophotometry, Atomic; D013194:Staining and Labeling; D013787:Thalamic Nuclei / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D011134:Polysaccharides; D010862:Pilocarpine; D008094:Lithium; D002118:Calcium