Concentration-related effects of hexane on evoked responses from brain and peripheral nerve of the rat

Sensory evoked responses were studied in 32 chronically implanted male Fischer-344 rats in order to characterize the electrophysiologic concomitants off hexacarbon polyneuropathy. The action potential (AP) of the ventral caudal (tail) nerve, the brainstem auditory-evoked response (BAER), and cortical somatosensory (SER)-, auditory- and visual-evoked responses were recorded from rats exposed to air or 500, 1000 or 1500 ppm hexane for 24 hrs/day, 5 days/week for 11 weeks. Concentration-related latency increases occurred within each sensory modality. The most pronounced effects were on the AP and SER. Latency of the fifth, but not the first, component of the BAER was prolonged, indicating an effect on central auditory tract conduction time. Amplitudes of response components were variable and rarely affected significantly by exposure to hexane.