The neurotoxic effects of ibotenic acid, quinolinic acid and kainic acid on cells in the rat striatum were investigated using immunocytochemistry with antibodies to the calcium binding proteins, calbindin and parvalbumin. The results showed that both ibotenic acid and quinolinic acid affected calbindin and parvalbumin cells to the same extent. However, parvalbumin immunopositive neurons were more sensitive than calbindin immunopositive neurons to the neurotoxic effects of kainic acid. Although the reason for this increased sensitivity of parvalbumin striatal neurons to kainic acid is unclear, these results suggest that the neurotoxicity produced by kainic acid is different to that occurring with quinolinic acid and ibotenic acid.