Influence of opioid receptor antagonists on motor-impairing effects of benzodiazepines.

The influence of naloxone and naltrexone on the motor-impairing effects of diazepam, chlordiazepoxide, clonazepam and estazolam were studied in the aerial righting reflex test (mice, rats), and the first two drugs were examined in the rota-rod test (mice). Benzodiazepine-induced motor incoordination was significantly decreased by naloxone and naltrexone (4-16 mg/kg) in mice and rats in aerial righting reflex test. The motor-impairing effects of diazepam and chlordiazepoxide observed in rota-rod test were significantly diminished only by naltrexone (8-16 mg/kg).

Effects of calcium channel antagonists on the reinforcing properties of morphine, ethanol and cocaine as measured by place conditioning.

Morphine, ethanol and cocaine were examined in place conditioning paradigm. After initial preferences were determined, animals were conditioned with morphine (5 mg/kg), ethanol (1 g/kg) and cocaine (5 mg/kg) alone or combinations of these drugs plus some calcium antagonists: nifedipine (5 and 10 mg/kg) and verapamil (5 and 10 mg/kg). Nifedipine prevented the ability of morphine and cocaine, but not of ethanol, to produce a place preference.

Rewarding properties of some drugs studied by place preference conditioning.

Ethanol, morphine, cocaine and amphetamine were examined in place conditioning. After determination of initial preferences, animals were conditioned with ethanol (1 g/kg), morphine (5 mg/kg), cocaine (5 mg/kg) and amphetamine (5 mg/kg) alone or with combinations of these drugs plus naloxone (1 mg/kg). Naloxone prevented the ability of all drugs used to produce a place preference.

Effects of opioid antagonists on anticonvulsant and hypnotic activity of benzodiazepines.

The influence of naloxone and naltrexone on the hypnotic and protective efficacy of diazepam, chlordiazepoxide, clonazepam and estazolam against electroshock- and pentylenetetrazole-induced seizures was studied in mice. Naloxone and naltrexone significantly decreased the anticonvulsant effects of diazepam and estazolam, but they did not changed that of chlordiazepoxide and clonazepam in electroshock-induced tonic hindlimb extension. Protective effects of benzodiazepines against pentylenetetrazole-induced seizures were slightly diminished by naloxone and naltrexone (16 mg/kg).

Ethanol and benzodiazepines. The influence of CGS 8216 on the ethanol-induced hypothermia and motor incoordination in mice and rats.

Ethanol has pharmacological profile very similar to benzodiazepines which facilitate GABA-ergic neurotransmission. In addition, a lot of ethanol-induced effects are partially antagonized by Ro 15-4513, a benzodiazepine inverse agonist. In our study, the influence of CGS 8216, another benzodiazepine inverse agonist, on the hypothermic (3.