Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats

Kruger K, Repges H, Hippler J, Hartmann LM, Hirner AV, Straub H, Binding N, Musshoff U

Abstract

In this study, the effects of pentavalent dimethylarsinic acid ((CH3)(2)AsO(OH); DMA(V)) and trivalent dimethylarsinous acid ((CH3)(2)As(OH); DMA(III)) on synaptic transmission generated by the excitatory Schaffer collateral-CA1 synapse were tested in hippocampal slices of young (14-21 day-old) and adult (2-4 month-old) rats. Both compounds were applied in concentrations of I to 100 mu mol/l. DMA(V) had no effect on the amplitudes of evoked fEPSPs or the induction of LTP recorded from the CA1 dendritic region either in adult or in young rats. However, application of DMA(III) significantly reduced the amplitudes of evoked fEPSPs in a concentration-dependent manner with a total depression following application of 100 mu mol/l DMA(III) in adult and 10 mu mol/l DMA(III). in young rats. Moreover, DMA(III), significantly affected the UP-induction. Application of 10 mu mol/l DMA(III) resulted in a complete failure of the postsynaptic potentiation of the fEPSP amplitudes in slices taken both from adult and young rats. The depressant effect was not reversible after a 30-min washout of the DMA(III). In slices of young rats, the depressant effects of DMA(III) were more pronounced than in those taken from adult ones. Compared to the (absent) effect of DMA(V) on synaptic transmission, the trivalent compound possesses a considerably higher neurotoxic potential. (c) 2007 Elsevier Inc. All rights reserved.