This investigation examined the relationship between alteration of Ca(2+)-transport systems and cytotoxicity in vitro for a number of neuroactive chemicals including environmental pollutants. (45)Ca(2+) uptake as a measure of Ca(2+) sequestration was determined in mitochondria and microsomes isolated from cerebella of adult male Long-Evans hooded rats by differential centrifugation. Ca(2+) extrusion, measured as Ca(2+)-ATPase activity, was determined in synaptosomes prepared by sucrose density gradient. Cytotoxicity (lactate dehydrogenase leakage) was assessed in primary cultures of cerebellar granule cells from 6- to 8-day old Long-Evans rats. N-Methyl-D-aspartic acid (NMDA) did not alter synaptosomal Ca(2+)-ATPase activity or (45)Ca(2+) uptake in mitochondria and microsomes. However, chlorpromazine (CPZ), aluminum (Al), permethrin (PER), and deltamethrin (DEL) inhibited Ca(2+) sequestration by mitochondria and microsomes. Of all the chemicals tested, CPZ was the most potent in inhibiting Ca(2+)-transporting systems and was also cytotoxic.