The effects of single doses of a novel 5-HT3 receptor antagonist, BRL 46470A (0.1 microgram, 0.01 mg, 1 mg or 50 mg) and lorazepam (2.5 mg) on psychometric performance and the EEG were investigated in a randomised, double-blind, crossover, placebo controlled study of 16 healthy male volunteers. 2. There was strong evidence that lorazepam had a marked effect on the EEG, increasing power in the 1 Hz to 7 Hz and 13 Hz to 20 Hz wavebands, whilst reducing power in the 8 Hz to 12 Hz waveband. Lorazepam also produced an impairment of daytime function as assessed by psychometric performance and subjective measures. 3. In contrast, there was little evidence to suggest that BRL 46470A had any effect on the EEG or that it impaired daytime function.
