Reversible effects of monothiol (D-penicillamine) and dithiol (dimercaptosuccinic acid) chelating compounds on methylmercury-inhibited choline acetyltransferase activity and high affinity choline uptake.
The effects of thiol compounds on methylmercury chloride (MMC)-inhibited choline acetyltransferase (ChAT) activity and MMC-inhibited high affinity choline uptake of rat brain tissue were studied in vitro. D-penicillamine (D-Pc) and dimercaptosuccinic acid (DMS) reversed the MMC-inhibited ChAT activity dose-dependently. Equilibrium dialysis of MMC-inhibited ChAT against the buffer containing 10(-3) M D-Pc reversed the ChAT activity almost completely. The reversal effect of D-Pc (monothiol compound) on MMC-inhibited ChAT was significantly more potent than that of DMS (dithiol compound). D-Pc and DMS almost equally reversed the MMC-inhibited high affinity choline uptake by synaptosomes in a dose dependent fashion. Washing with a solution containing D-Pc or DMS equally reversed the MMC-inhibited high affinity choline uptake in a dose-dependent fashion. Neither D-Pc nor DMS could reverse the hemicholinium-3-inhibited high affinity choline uptake.
D000042:Absorption; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology*; D002794:Choline / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000037:antagonists & inhibitors*; D003956:Dialysis; D008297:Male; D008767:Methylmercury Compounds / Q000037:antagonists & inhibitors*; D010396:Penicillamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D004113:Succimer / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000494:pharmacology*
D002614:Chelating Agents; D008767:Methylmercury Compounds; D013438:Sulfhydryl Compounds; D004113:Succimer; D002795:Choline O-Acetyltransferase; D010396:Penicillamine; D002794:Choline; C004925:methylmercuric chloride