Survival of dentate hilar mossy cells after pilocarpine-induced seizures and their synchronized burst discharges with area CA3 pyramidal cells
Section snippets
Experimental procedures
Animal care and use met the guidelines set by the National Institutes of Health and the New York State Department of Health. All efforts were made to minimize the number of animals used and their suffering. All chemicals were purchased from Sigma (St. Louis, MO, USA) unless otherwise noted.
Results
This study is based on 42 mossy cells recorded from 21 animals. Eight were injected with pilocarpine and had status epilepticus followed by recurrent seizures. The number of seizures that were witnessed ranged from three to 42, but this is quite likely to be an underestimate because observations were not made continuously (see Experimental procedures). These rats are referred to below as ‘epileptic’. Slices were made 1–6 months after status, and 20 mossy cells were recorded.
Six rats were
Summary
The results suggest that mossy cells can survive status epilepticus and chronic seizures in rats. The cells that survived had similar morphological and intrinsic electrophysiological properties as mossy cells from saline controls, but had spontaneous and evoked epileptiform discharges. These discharges were synchronized with epileptiform bursts of area CA3 pyramidal cells. Simultaneous intracellular recording showed that the majority of pyramidal cell bursts occurred prior to mossy cell burst
Acknowledgements
We thank Annmarie Curcio and Ruth Marshall for technical and secretarial assistance. This study was supported by NIH Grant 38285 to H.E.S.
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