Abstract
The effects of thiol compounds on methylmercury chloride (MMC)-inhibited choline acetyltransferase (ChAT) activity and MMCinhibited 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 10-3M 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 dosedependent fashion. Neither D-Pc nor DMS could reverse the hemicholinium-3-inhibited high affinity choline uptake.
