Alterations in flash evoked potentials (FEPs) in rats produced by 3,3'-iminodipropionitrile (IDPN).

3,3'-Iminodipropionitrile (IDPN) is a neurotoxicant that produces changes in flash evoked potentials (FEPs) 18 weeks after treatment. We examined dose- and time-related effects of IDPN on FEPs at earlier time points than previously studied (52). Adult male Long-Evans rats were given IDPN (0, 100, 200, 400 mg/kg/day x 3 days, i.p.) and FEPs were recorded 14 days later. IDPN (400 mg/kg/day) decreased the amplitudes of some of the "early" and "middle" FEP peaks (n30 and N56), and increased the latencies of some early peaks (P21 and P46). A separate group of rats was treated with IDPN (0 or 400 mg/kg/day x 3 days, i.p.) and FEPs were recorded 1, 3, 7, 14, and 35 days later. The latencies of of all portions of FEPs were increased by IDPN, with maximal changes occurring at 7 and/or 14 days. The amplitude of the middle portions of FEPs (peaks N56, P63, N70, P90) were altered as early as day 3, and some changes were observed up to day 14. In contrast, the "late" portion of FEPs (peak N160) was affected at later times (days 14 and 35). Corneal opacities were noted on days 3 and 7, but were largely reversible by day 14. In the time-course study, IDPN decreased colonic temperature on days 1, 3, 7, and 14. The present results suggest that IDPN alters both the early FEP peaks related to the initial afferent sensory volley, and cortical processing associated with the middle and later portions of FEPs.