Calcium uptake in brain synaptosomes from rats exposed to daily toluene for up to 80 weeks

Rats were exposed to toluene, 500 p.p.m., for 12 hrs/day for up to 80 weeks. The brains were removed and the synaptosomes were prepared. Potassium-stimulated and unstimulated synaptosomes were incubated with 45Ca2+ for 1/2, 2, 4, 8, and 16 min. Toluene exposure for 4 and 12 weeks caused a significant, approximately 20%, increase in 45Ca2+ uptake into unstimulated synaptosomes. The effect was of moderate quantity and transient, since it was not significant after 30 and 80 weeks of exposure. It seems doubtful whether the demonstrated change in calcium uptake should have any relevance in connection with the "organic solvent neurotoxicity syndrome".