Effects of repeated exposure of rats to JP-5 or JP-8 jet fuel vapor on neurobehavioral capacity and neurotransmitter levels

The U.S. Naval Service is anticipating transition from the nearly exclusive use of JP-5 jet fuel to predominant use of JP-8, consistent with the prima ry utilization by the U.S. Army, U.S. Air Force, and the militaries of most NATO countries. To compare the relative risk of repeated exposure to JP-5 versus JP-8 vapor, groups of 32 male Sprague-Dawley rats each were exposed for 6 h/d, 5 d/wk for 6 wk (180 h) to JP-8 jet fuel vapor (1000 +/- 10% mg/ m(3)), JP-5 vapor (1200 +/- 10% mg/m(3)), or room air control conditions. F ollowing a 65-d rest period, rats completed 10 tests selected from the Neur obehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in perfo rmance capacity. Repeated exposure to JP-5 resulted in significant effects on only one test, forelimb grip strength (FGS), while exposure to JP-8 vapo r resulted in a significant difference versus controls on appetitive reinfo rcer approach sensitization (ARAS). Rats were further evaluated for concent rations of major neurotransmitters and metabolites in five brain regions an d in the blood serum. Levels of dopamine, the dopamine metabolite dihydroxy phenylacetic acid (DOPAC), and the serotonin metabolite homovanillic acid ( HVA) were significant ly modulated in various brain regions, as measured 85 + d postexposure. Similarly, serum levels of the serotonin metabolite 5-hyd roxyindoleacetic acid (5-HIAA) were differentially modulated following JP-8 or JP-5 exposure. Results are compared to previously published research ev aluating the neurotoxicity of repeated exposure to other hydrocarbon fuels and solvents.