DEAROMATIZED WHITE SPIRIT INHALATION EXPOSURE CAUSES LONG-LASTING NEUROPHYSIOLOGICAL CHANGES IN RATS

Dearomatized white spirit inhalation exposure causes long-lasting neur ophysioloical changes in rats. NEUROTOXICOL TERATOL 18(1), 67-76, 1996 . -Exposure for 6 h per day, 5 days per week, during a period of 6 mon ths to the organic solvent dearomatized white spirit (0, 400, and 800 ppm) was studied in rats that were 3 months old when the repeated expo sure was initiated. After an exposure-free period of 2-6 months durati on, neurophysiological, neurobehavioral, and macroscopic pathologic ex aminations were performed. The study revealed exposure-related changes in sensory evoked potentials and a decrease in motor activity during dark (no light) periods but no white spirit-induced changes in learnin g and memory functions. The measurements of the flash evoked potential (FEP), somatosensory evoked potential (SEP), and auditory brain stem response (ABR) all demonstrated dose-dependent increases of the amplit udes of the early latency peaks of the sensory evoked potentials (EPs) . Furthermore, an increase of the dose showed that the measurements of FEP and SEP revealed changes in the later-latency peaks, which reflec t the more associative aspects of sensory processing. The results demo nstrated that 6 months of exposure to dearomatized white spirit induce d long-lasting and possible irreversible effects in the nervous system of the rat.