Accumulation of calcium in the rat hippocampus during kainic acid seizures.

The change in the total calcium content of the rat hippocampus was investigated quantitatively and the sites of the accumulated calcium in the CA1 region were demonstrated cytochemically by the oxalate-pyroantimonate technique 4 h following intraperitoneal kainic acid administration. Kainic acid was found to induce a significant increase in the total calcium content of the hippocampus (from 4.75 +/- 0.39 to 6.64 +/- 0.60 mumol/g dry weight). Calcium accumulated mainly in the mitochondria of the neuronal somata, the dendrites and the synaptic terminals. Consequently, the degenerative alterations caused by kainic acid are associated with intracellular calcium accumulation, which can overload the capacity of the mitochondria for calcium sequestration, and may have a role, besides other factors, in the development of neuronal damage.