Effects of the benzodiazepine inverse agonist RO19-4603 alone and in combination with the benzodiazepine receptor antagonists flumazenil, ZK 93426 and CGS 8216, on ethanol intake in alcohol-preferring (P) rats

Brain Res. 1996 Sep 23;734(1-2):19-34.

Abstract

The present study investigated dose dependence and time course effects of the benzodiazepine (BDZ) partial inverse agonist, RO19-4603 (0.005-0.30 mg/kg) alone, and in combination with the BDZ receptor antagonists flumazenil, ZK 93426, and CGS 8216 (20 mg/kg) in selectively bred alcohol-preferring (P) rats provided a two-bottle choice test between ethanol (EtOH) (10% v/v), and a palatable saccharin (0.0125% g/v) solution. A single dose of RO19-4603 as low as 0.009 mg/kg selectively reduced EtOH drinking during the initial 15 min of a 4 h access to 19-0% of control levels on day 1. The 0.08, 0.15 and 0.30 mg/kg doses of RO19-4603 significantly reduced total EtOH intake in the 4 h access period to 57-45% of controls on day 1. On day 2, no RO19-4603 injections were given; however, six of the seven doses of RO19-4603 (0.009, 0.02, 0.04, 0.08, 0.15, and 0.30 mg/kg) continued to reduce EtOH intake to 42-3% of control levels at the initial 15 min interval, while the 0.005, 0.009, 0.08, and 0.30 mg/kg doses reduced total 4 h EtOH intake to 60-42% of controls. Saccharin intake was either not altered by RO19-4603 or showed increases during the initial 15 min intervals and the total 4 h sessions on days 1 and 2. Food intake was also unaffected by RO19-4603. The CGS 8216, but neither flumazenil nor ZK 93426, reliably reversed the RO19-4603-induced suppression of EtOH intake on days 1 and 2. That certain BDZ inverse agonists can attenuate motivated behavior for EtOH reinforcement over a prolonged time course may provide a possible therapeutic approach to reducing EtOH consumption associated with alcoholism.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alcohol Drinking*
  • Animals
  • Azepines / pharmacology*
  • Benzodiazepines / agonists*
  • Dose-Response Relationship, Drug
  • Drinking / drug effects
  • Drug Combinations
  • Eating / drug effects
  • Ethanol
  • Female
  • Flumazenil / pharmacology*
  • GABA-A Receptor Antagonists*
  • Pyrazoles / pharmacology*
  • Rats
  • Saccharin
  • Solutions
  • Time Factors

Substances

  • Azepines
  • Drug Combinations
  • GABA-A Receptor Antagonists
  • Pyrazoles
  • Solutions
  • Benzodiazepines
  • Ethanol
  • Flumazenil
  • 2-phenylpyrazolo(4,3-c)quinolin-3(5H)-one
  • Ro 19-4603
  • Saccharin