You are here:
Acute inhalation of 2,2,4-trimethylpentane alters visual evoked potentials and signal detection behaviour of rats.
Citation:
BOYES, W. K., L. DEGN, M. S. BERCEGEAY, W. M. OSHIRO, AND P. J. BUSHNELL. Acute inhalation of 2,2,4-trimethylpentane alters visual evoked potentials and signal detection behaviour of rats. Presented at Society of Toxicology, Seattle, WA, March 16 - 20, 2008.
Impact/Purpose:
We evaluated potential neurological impairment from acute inhalation exposure to TMP in adult male Long-Evans rats using both electrophysiological and behavioral assessments.
Description:
The volatile organic compound 2,2,4-trimethylpentane (TMP, “isooctane”) is a primary constituent of gasoline for which the current health effects data are insufficient to permit EPA to conduct a risk assessment. We evaluated potential neurological impairment from acute inhalation exposure to adult male Long-Evans rats using both electrophysiological and behavioral assessments. Rats (n=9-10/dose) were exposed to TMP vapors in concentrations of 0, 500, or 1000 ppm. Visual evoked potentials were recorded from electrodes previously implanted in visual cortex while the rats viewed modulating visual patterns (0.16 cpd, 60% contrast, 4.55 Hz appear/disappear). VEPs were recorded before exposure, every 10 min during a 60 min exposure session, and for an additional 60 min after exposure terminated. The spectral amplitude of the frequency-double component (F2) was significantly reduced by 500 or 1000 ppm TMP exposure. In behavioral assessment, rats (n=14) performed a signal-detection operant task while breathing 0, 500, 1500, 2000, or 2500 ppm TMP for 62 min. Slight reductions were observed in accuracy measures at the 2000 and 2500 ppm concentrations. Together these data demonstrate that TMP, like other volatile organic substances, impairs neurological function during acute inhalation exposure. This abstract does not reflect EPA policy.