Distribution of HSP72 induction and neuronal death following limbic seizures.

A small area of deep prepiriform cortex is uniquely susceptible to convulsant and anticonvulsant drugs in the rat. We have studied the pattern of expression of the non-constitutive stress protein (HSP72) following seizures induced by unilateral microinjection of bicuculline into this area. HSP was seen first in ipsilateral dorsal medial thalamus, amygdala and associated piriform cortex, and with more sustained seizures was seen bilaterally in these structures as well as in other projection sites. Neuronal cell death, as assessed by acid-fuchsin staining, occurred in the same brain regions. Frank necrosis was found in the ipsilateral piriform cortex with prolonged seizures. Behaviorally, the seizures induced are characteristic of involvement of the limbic system and, therefore, may be a model of human complex partial seizures.