A comparative study between two drugs acting on the GABAA receptor,
alprazolam and
alpidem was undertaken, using simple tests such as measurement of spontaneous locomotor activity, four plates test and rotarod in mice. Additional conflict test was further performed using a new conflict paradigm where the opportunity existed for rats to choose during punished periods between immediate, punished reinforcement and delayed non-punished reinforcement. The
benzodiazepine alprazolam, demonstrated, as expected, strong
anxiolytic effects in mice and increased punished response in rats at non
sedative doses (0.5, 1 mg/kg). High doses of
alprazolam decreased spontaneous locomotor activity and induced myorelaxant effects in mice.
Alpidem, an
imidazopyridine derivative, induced motor impairment in mice and only very weak
anxiolytic effects in the four plates test in mice (4 mg/kg) and in punished procedure in rats (32 mg/kg). As
alprazolam is a full agonist for the GABAA receptor complex and
alpidem is a partial agonist acting with specificity on omega 1 GABAA receptor subtypes, the results are discussed. Activity on omega 1 receptor subtypes is perhaps not sufficient in order to obtain a true anti-conflict effect and compounds such as
alpidem only relieve some of the symptoms of
anxiety disorders.