Interaction of caffeine with benzodiazepines: behavioral effects in mice

Three series of behavioral experiments, i.e. hole-board, open-field and spontaneous motor activity test, were carried out on mice with the goal of determining the effects of the interaction between caffeine and two peculiar benzodiazepines (BDZ). The drugs, desmethyldiazepam (DMDZ) and chlor-desmethyldiazepam (Cl-DMDZ), were administered acutely by the intraperitoneal route. In preliminary experiments, the effects of several doses of caffeine were examined in the three in order to obtain some indication of the doses to use for interaction experiments. Therefore, stimulant doses of caffeine (5, 10 and 20 mg/kg) were associated with the two benzodiazepines. It was found that BDZ counteracted the effect of caffeine in the hole-board and in the spontaneous motor activity tests. By contrast, in the open-field situation, the association always gave rise to an increase in exploration activity. Furthermore, the present investigations showed, once again, that chlor-desmethyldiazepam is more active than the other benzodiazepine.