The central pharmacological effects of ethanol are well known and rese
mble those of the benzodiazepines (BZD). In addition BZD may interact
with ethanol, resulting in enhanced cerebral depression. Ro 15-4513, B
ZD inverse agonist, potentially antagonizes a lot of effects of ethano
l but not all. In our study, another BZD inverse agonist, CGS 8216, re
verses the hypnotic effect of ethanol and hypoactivity in mice and rat
s. CGS 8216 increased also ethanol's locomotor stimulation in mice. Th
is supports the hypothesis that some effects of ethanol are mediated b
y the GABA-BZD-chloride channel receptor complex. Our behavioural expe
riments described in this report suggest that CGS 8216, like Ro 15-451
3, may act on the alpha-6 subunit of this receptor complex.