Effects of arsenite on long-term potentiation in hippocampal slices from young and adult rats

Kruger K, Binding N, Straub H, Musshoff U

Abstract

The effects of trivalent arsenite were tested at the Schaffer collateral-CA I synapse of adult (2-4 month) and young (14-21 days) rats. Exposure of 100 mu mol/l arsenite led to a slight and reversible reduction Of the amplitudes Of evoked excitatory postsynaptic field potentials in adult and young rats, while exposure of 0.1 and 1 mu mol/l arsenite had no effects. The long-term potentiation (LTP) was significantly inhibited by arsenite in adult but not ill rats. Exposure of 0.1.1 and 100 mu mol/l arsenite to slices of adult rats before and during the UP Stimulus led to a significant reduction in the potentiated amplitudes amounting to a maximum of 50% of the control values. In young, animals. however, exposure of I mu mol/l arsenite showed no effect on the UP potentiated amplitudes. while exposure of 100 mu mol/l arsenite led initially to a significant reduction in the amplitudes, compared to the control level. which was completely reversible 20 min after washout. Exposure of 100 [mu mol/l arsenite did not affect the paired-pulse facilitation. indicating that arsenite does not exert its effects by influencing presynaptic transmitter release mechanisms. (c) 2006 Elsevier Ireland Ltd. All rights reserved.