Ro 15-4513 selectively attenuates ethanol,but not sucrose,reinforced responding in a concurrent access procedure: comparison to other drugs |
| |
Authors: | Nancy M Petry |
| |
Institution: | (1) Department of Psychology, William James Hall, Harvard University, 33 Kirkland Street, 02138 Cambridge, MA, USA;(2) Present address: Department of Psychiatry, University of Vermont, Substance Abuse Treatment Center, Arnold 6, 1 South Prospect Street, 05401 Burlington, VT, USA |
| |
Abstract: | The experiments described in this report used a concurrent access procedure to study ethanol reinforcement. Rats were trained to lever press for a 10% sucrose solution and a 10% ethanol/10% sucrose mixture, and both reinforcers were available on variable-interval 5-s schedules. In baseline and vehicle injection sessions, the animals distributed their responding between both solutions. When injected with the partial inverse benzodiazepine agonist Ro 15-4513 (3, 9, and 18 mg/kg), responding for the ethanol solution decreased while responding for sucrose remained intact. Ethanol injections (0.5 and 1.0 g/kg) engendered a similar profile. Chlordiazepoxide led to an increase in ethanol mix responding at 2 mg/kg and a decrease in ethanol mix responding at higher doses; no dose affected sucrose responding. Morphine (0.5–16 mg/kg) decreased responding for both the ethanol mix and sucrose solutions, more or less simultaneously. Naloxone (0.125–20 mg/kg) selectively reduced ethanol mix responding at low doses, and decreased responding for both reinforcers at high doses. In another group of animals, isocaloric alternatives were concurrently available: 10% ethanol/0.25% saccharin versus 14% sucrose. Injections of Ro 15-4513 and chlordiazepoxide produced similar results as in the first group of rats: an increase in ethanol mix responding with low dose chlordiazepoxide, and a decrease in ethanol mix responding with Ro 15-4513. However, naloxone injections did not selectively affect responding for either of the reinforcers when they were isocaloric. These results are discussed in terms of ethanol's neuropharmacological actions. |
| |
Keywords: | Ethanol self-administration Ro 15-4513 Chlordiazepoxide Naloxone Morphine Lever-press Rats |
本文献已被 SpringerLink 等数据库收录! |
|