HaloperidolおよびDiazepamの視覚誘発電位(VEP)および脳波への急性効果

The acute effects of haloperidol (HLP) and diazepam (DZP) on the Visual Evoked Potential (VEP) and EEG were studied with 16 healthy male subjects (26~43 y.o.). In the two experimental session for each subject, HLP (0.02 mg/kg) were intra-venously and DZP (0.1 mg/kg) were per-orally administered. EEGs and VEPs were recorded through the two derivations (2 ch : O1→A1+2, 5 ch : O1→Cz), with 1024 msec of analysis time, averaging 100 responses. In the experimental session, EEGs and VEPs were recorded before and 15, 30, and 45 min after administration of HLP, before and 30,60, and 90 min after DZP. Consecutive change of group mean VEP were studied. Individual VEPs were subjected to the component analysis, and to the statistical assessment together with EEG. The following results were obtained.
1. After the administration of HLP, the latencies of short, middle and long latency component significantly increased, and the peak-to-peak amplitude N 1-P 2, P 5-N 5 and N 5-P 6 significantly decreased. The largest peak-to-peak amplitude P 4-N 7 significantly increased. In EEG, δ and θ-power% increased, and α2-power% decreased significantly. Significant positive correlation was found between δ, θ-power% of EEG and VEP latencies, and significant negative correlations was found between α2-power% and VEP latencies. These findings indicate the inhibitory effect of HLP all over the visual system through dopaminergic neuron system. The largest peak-to-peak amplitude (P 4-N 7) increased significantly synchronizing with increased θ waves.
2. After the administration of DZP, the latencies of short and middle latency component, P 3 and P 5, increased, P 2 latency decreased significantly. The peak-to-peak amplitude P 3-N 3, N 3-P 4, P 5-N 5, and N 5-P 6 decreased, N 2-P 3 amplitude increased significantly. In EEG, β1-power% increased, and α2-power% decreased significantly. Significant negative correlation was found between δ, θ-power% of EEG and VEP amplitudes, and positive correlations between α2-power% and VEP amplitudes. These findings indicate the inhibitory effect of DZP mainly on lateral geniculate body, optic radiation, and up to the visual cortex making BZD-receptor and GABA-receptor complex. Some exciting effect of DZP before the lateral geniculate body was suggested.