3-Methylindole alters both olfactory and trigeminal nasal mucosal potentials in rats

Data from human studies imply that vanillin is an olfactory stimulant, wher eas CO2 activates intranasal trigeminal nociceptors. We examined the effect s of the olfactotoxin 3-methylindole (3-MI) on nasal mucosal potentials evo ked by vanillin and CO2 in rats. A single i.p. administration of 300 mg/kg 3-MI altered both olfactory and trigeminal mucosal responses. Relative to a mplitude values determined in non-3-MI-injected rats, the response to vanil lin was reduced to 6%, 7%, and 43%, and the response to CO2, recorded in th e same rats, decreased to 25%, 38%, and 51% at 4, 8 and 16 days post-3-MI, respectively. The results suggest that 3-MI affects both olfactory and trig eminal elements within the nasal mucosa. NeuroReport 11:2195-2197 (C) 2000 Lippincott Williams & Wilkins.