Adenosinergic system is involved in development of diazepam tolerance in mice

In the present study the effect of adenosinergic system on the development of diazepam tolerance to motor disturbances in mice was investigated. Diazepam tolerance was obtained by administration of diazepam at a dose of 5.0 mg/kg, s.c. for ten consecutive days. On the 1st and the 10th day of the experiment motor impairments were measured in two behavioural tests: rota-rod and chimney test. We showed that acute diazepam injection produced significant motor impairments in mice and that effect was decreased by repeated diazepam treatment, confirming the development of tolerance to the motor impairing effect of diazepam. We demonstrated that adenosine A1 and/or A2A receptor agonists: CPA (0.025 and 0.05 mg/kg, i.p.), CGS 21680 (0.1 and 0.2 mg/kg, i.p.), NECA (0.005 and 0.01 mg/kg, i.p.) pretreatment with diazepam were able to attenuate the development of diazepam tolerance and adenosine receptor antagonists: DPCPX (1.0 and 3.0 mg/kg, i.p.), DMPX (3.0 and 6.0 mg/kg, i.p.) and caffeine (10.0 and 20.0 mg/kg, i.p.) induced the opposite effect. The most apparent effects were obtained by non-selective agonist (NECA) and antagonist (caffeine) of adenosine receptors. We conclude that adenosinergic system plays an important role in mechanisms underlying the development of benzodiazepine tolerance.