HEXAFLUORODIETHYL ETHER (INDOKLON) CONVULSIONS IN CORPUS-CALLOTOMIZED WHITE RATS

Abstract

The convulsant threshold of 24 corpus-callotomized Sprague–Dawley rats exposed to Indoklon vapor once a week was found to be significantly lower than that of 24 sham-operated controls in the second, third, and fourth exposures; the sensitivity of both groups of animals increased progressively and levelled out at the fifth exposure. Repetition of the experiment after 3 weeks of rest, with exposures spaced at 48-hour intervals, further lowered the convulsant threshold of the animals, both groups exhibiting a similar, and possibly maximal, sensitivity to Indoklon at the second exposure. When in another series, 60 corpus-callotomized rats and 60 sham-operated controls were injected intraperitoneally with CD10 of Indoklon at weekly intervals, the susceptibility of both groups to convulsions again increased rapidly during the first four injections; at the second injection, the corpus-callotomized rats were significantly more sensitive to Indoklon than the controls. During the fifth to eighth injection, the convulsibility of the animals reached a plateau, 62.2% to 78.5% of the rats convulsing; the difference between the two groups at this stage became less marked, though the convulsions in corpus-callotomized animals continued to be of longer duration than in the controls. Repetition of the injections, spaced at 48-hour intervals, after 3 months of rest, demonstrated a continuing high and equal sensitivity of the two groups of rats to Indoklon with some depression setting in during the second half of a series of 12 injections.