Chlordiazepoxide Effects on Ethanol Self‐administration: Dependence on Concurrent Conditions

Abstract

Experiments examined the effects of acute doses of chlordiazepoxide upon ethanol selfadministration in the rat. A concurrent-schedule procedure was used that employed choice between ethanol (5%) and a second fluid (either water or a 1% sucrose solution). When ethanol and water were the available fluids, chlordiazepoxide at doses of 15 and 20 mg/kg reduced ethanol-reinforced responding and intake, with a greater reduction occurring at the 20 mg/kg dose. However, when ethanol and sucrose were concurrently available, in many rats only the 20 mg/kg dose of chlordiazepoxide reduced ethanol-reinforced responding. The differences in dose response function occurred in most animals without large changes in the baseline ethanol-reinforced responding across the two concurrent conditions. Thus the dose-effect curve relating chlordiazepoxide and ethanol self-administration can be altered, dependent upon the nature of the concurrently available reinforcers.

Fluvoxamine effects on concurrent ethanol- and food-maintained behaviors.

“…However, stimulus control has a lesser impact on effects of pentobarbital, chlorpromazine, and promazine (Laties, 1972;Katz, 1983). No data is available on whether stimulus control modulates the effects of fluvoxamine or related drugs; therefore additional studies are necessary to interpret the present results in terms of altered stimulus control.Another possible explanation suggested by Samson and Grant (1985) that could relate to our results is that the addition of concurrent food availability alters the demand curve for ethanol (Hursh, 1993). Concurrent access to food could increase the elasticity of demand for ethanol.…”

“…Because the rats in this study were not water-deprived, it is unclear that water was reinforcing lever-pressing (as evidenced by low rates of responding on the water-associated lever). The increased resistance to disruption of responding for ethanol by chlordiazepoxide when sucrose was concurrently available did not appear to be due to changes in the baseline rate of responding for ethanol as baseline rates did not differ between conditions (Samson and Grant, 1985).Early studies suggested that selective serotonin reuptake inhibitors (SSRI), including fluvoxamine, could reduce ethanol intake in laboratory animals (Murphy et al, 1985;Maurel et al, 1999). Further research indicated that fluvoxamine could selectively reduce operant responding maintained by ethanol when compared with responding maintained by food (Lamb and Järbe, 2001).…”

“…Rats were not water-deprived, and when water was the available alternative, response-rates were low on the water-associated lever, and water was not clearly reinforcing lever-pressing (Samson and Grant, 1985). However when sucrose was available, response rates on the sucroseassociated lever were similar to response-rates for ethanol and responding for ethanol was relatively more resistant to decrements following acute chlordiazepoxide treatments (Samson and Grant, 1985).Similarly, responding for ethanol was more sensitive to naltrexone than responding for food under independent progresssive ratios (Rodefer et al, 1999). However, the effects of a related drug (naloxone) were far less robust under a concurrent variable-interval variableinterval (VI VI) schedule for both ethanol and food (Petry, 1995).…”

“…Results of studies utilizing food-reinforcement suggest that behavioral momentum may influence pharmacologic disruption of drug-maintained behavior. Samson and Grant (1985) suggested that stimulus control could be altered when an alternative is concurrently available, which could impact the effects of pharmacologic agents on drug-maintained behavior. They also suggest that the presence of a concurrently available alternative could alter the demand curve for self-administered drug.…”

Central Opioid Receptors Differentially Regulate the Nalmefene-Induced Suppression of Ethanol- and Saccharin-Reinforced Behaviors in Alcohol-Preferring (P) Rats

“…The importance of alternative and concurrently available reinforcers in EtOH-maintained responding paradigms has been previously (Carroll et al, 1991;Heyman and Oldfather, 1992;Petry and Heyman, 1995;Rodefer et al, 1999;Samson and Grant, 1985) and recently (June, 2002) addressed. In addition, no studies could be found in the literature that have used neuroanatomical control groups to evaluate site-specific effects on EtOH-motivated behaviors, or motivated behaviors initiated by a palatable alternative solution.…”