Increasing or decreasing nervous activity modulates the severity of the glio-vascular lesions of 1,3-dinitrobenzene in the rat : effects of the tremorgenic pyrethroid, bifenthrin, and of anaesthesia

To test the hypothesis that altered neuronal activity may influence the extent and severity of the glio-vascular lesions produced by 1,3-dinitrobenzene (DNB), rats were either given the tremorgenic pyrethroid, Bifenthrin, or anaesthetised during various dosing schedules of DNB. When compared with controls dosed only with DNB, Bifenthrin tremor made both the ataxia and other functional effects caused by DNB more pronounced. Lesions in the brain stem were made significantly more severe and widespread across three dose levels of DNB. Centres such as facial nuclei, motor nuclei of fifth nerve, subthalamic nuclei and mamillary bodies, not damaged by DNB alone, were also affected in some animals. In contrast, general anaesthesia by either isoflurane ur urethane decreased the severity of the lesions, this being more pronounced with urethane. The character of the tissue changes, however, was not altered by these additional procedures. These findings support the suggestion that neuronal activity is one important determinant of the selective vulnerability of sensitive brain stem nuclei to glio-vascular damage from DNB intoxication.