Abstracts

RATIONALE: We reported a characteristics of substantia nigra seizures induced by a local injection of kainic acid(KA) into substantia nigra pars reticulata (SNr): Brain Research 911(2001) 89-95. It has been postulated that excessive influx of calcium into cells and subsequent accumulation of calcium in mitochondria leads to cell damage in various pathological conditions. The occurrence of cell damage caused by the failure of calcium homeostasis has been reported in the following pathological conditions: muscle cell necrosis in muscular dystrophy, myocardial infarction, hepatic ischemia and seizures. In the present study, the sites of calcium accumulation were studied by ⁴⁵ Ca autoradiography during kainic acid (KA)-induced substantia nigra seizure in rats.
METHODS: Eight Wistar male rats (250-330g) were used. Under intraperitoneal pentobarbital anesthesia (45mg/kg), a stainless-steel cannula was inserted stereotaxically into the left SNr for KA injection. At 7 days after surgery, 1microgram of KA was injected into the left SNr (4 rats) and 1microgram of physiological saline was injected into the left SNr (4 rats). About two hour after KA injection, ⁴⁵ Ca was injected through the cannula in the femoral vein. Autoradiograms were prepared by exposing an X-ray film to the dried sections for 14 days in an X-ray cassette.
RESULTS: In ⁴⁵ Ca autoradiogram, the sites of calcium accumulation were as follows: hippocampus [gt] thalamus [gt] pretectal area [gt] substansia nigra [gt] amygdala [gt] lateral septal nucleus [gt] caudate nucleus [gt] globus pallidus.
CONCLUSIONS: Discussion and conclusion:These results suggested that regional calcium accumulation by SNr seizures not only involved the secondary generalization of the seizures but also might be responsible for neuronal cell damages.