Disruption of axonal transport from olfactory epithelium by 3-methylindole

The effects of 150, 350, and 400 mg/kg intraperitoneal 3-methylindole (3-MI) on anterograde transport of horseradish peroxidase from the olfactory epithelium to the olfactory bulb were investigated. In 400 mg/kg 3-MI-treated rats sacrificed after 7 days only about 2% of all glomeruli had normal levels of the reaction product, and most glomeruli had no detectable reaction product. Lower doses of 3-MI produced correspondingly less disruption of axonal transport, with savings located primarily in the ventral to midlateral and the ventromedial region of the bulb. There was a gradual recovery of bulbar connections in 12-, 22-, and 92-day survival rats. In all cases, the increase in axonal transport was greatest in glomeruli on the lateral, ventral, and ventromedial areas of the bulb, and least evident or absent on the dorsal and dorsomedial areas.