Age-related changes in rat brain ATPases during treatment with chlordecone

Chlordecone was reported to produce neurotoxicity by modulating the Na+ pump in adult rat brain. The present in vitro and in vivo studies were initiated to investigate its effect on maturing rat brain ATPases. Neonates were exposed to chlordecone for 20 d indirectly through lactation by treating the mothers po and from 21 to 50 d as adults. Brain P2 fractions were prepared from treated and control rats. Na+,K+, oligomycin-sensitive (O.S.) and oligomycin-insensitive (O.I.) Mg2+-ATPase activities were increased with age up to d 20. Na+,K+- and O.S. Mg2+-ATPases were inhibited in both in vitro and in vivo treatment with chlordecone. Both these enzymes were more sensitive to chlordecone in the neonatal brains as compared to adult rats (20-50 d). The activity of Mg2+-ATPase but not of Na+,K+-ATPase was restored to normal activity after 20 d of withdrawal of chlordecone treatment. O.I. Mg2+-ATPase was insensitive to chlordecone treatment in all age groups. Ca2+-ATPase activity was not increased with age; however, it was more sensitive to chlordecone in neonates as compared to adults. These results suggest that the Na+ pump, Ca2+-ATPase, and ATP synthesizing enzymes are highly sensitive to chlordecone during early postnatal development.