Abstract
Chronic experimental epilepsy was produced in adult female Sprague-Dawley rats by the implantation of cobalt wire into the right parietal cortex. Rats treated similarly with glass rods were used as controls. All animals were simultaneously prepared with permanent cortical and temporalis muscle electrodes for EEG and EMG recording. Administration of pentylenetetrazol i.p. at a dose of 15 mg/kg every 15 min until the appearance of generalized convulsions resulted in the lowering of the chemical seizure threshold expected for the cobalt-treated rats, with only 2 injections of the drug required in contrast to the 3 to 4 injections needed for the control rats. Analysis of the EEG recordings collected over the 24 h period after the first injection revealed the presence of a more pronounced suppression of REM sleep in the cobalt-epileptic rats. This effect was found to be due to a reduction in the total number of REM sleep episodes, while the duration of the individual episodes remained unchanged. The latencies to REM onset in these rats, moreover, were markedly reduced. These results in a chronic seizure model further support the usefulness of cobalt experimental epilepsy in the rat for the study of human seizure disorders in comparison with acute seizure models.
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Supported by the Epilepsy Foundation of America; a preliminary report on this work appeared in the Pharmacologist 15, 196 (1973).
U.S. Public Health Service Predoctoral Fellow; Supported by Training Grant TO1 GM 0076.
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Colasanti, B.K., Craig, C.R. & Hartman, E.R. Differential effects of pentylenetetrazol on REM sleep in naive and cobalt-epileptic rats. Psychopharmacologia 37, 151–157 (1974). https://doi.org/10.1007/BF00437421
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DOI: https://doi.org/10.1007/BF00437421