Blockade of Striatal Dopamine D1 Receptors Reduces Quinine-Resistant Alcohol Intake

Abstract

Drinking despite aversive consequences, or compulsive drinking, is a criterion of alcohol use disorder and can be modeled in rodents by adding bitter quinine into alcohol. Previous studies have shown the development of quinine-resistant ethanol (EtOH) drinking following a drinking history, but used animals that achieved relatively low blood alcohol levels. Selectively bred crossed High Alcohol Preferring (cHAP) mice average over 250 mg/dl during a two-bottle choice procedure. Compulsive drinking is hypothesized to be D1-receptor mediated via the dorsolateral striatum (DLS). We hypothesized that 2 weeks of free-choice EtOH would lead to quinine resistance and intra-DLS infusion of a D1-antagonist, SCH23390, would attenuate quinine-resistant alcohol drinking with no effect on non-conflicted EtOH drinking. Infusion of SCH23390 into the DMS would not affect quinine-resistant drinking. cHAP mice had guide cannulae placed in the DLS or DMS and had either two weeks (2W) of EtOH and water two-bottle choice or were EtOH naïve (0W). Mice were infused with either SCH23390 or saline immediately prior to one 10% EtOH and water test day and SCH23390 did not disturb alcohol drinking. The following day, we adulterated the EtOH with 0.32-g/L quinine (0.89 mM), and mice received the same microinjection. For animals cannulated in the DLS, 2W history group infused with saline drank more quinine-adulterated EtOH than the 0W saline mice. While SCH23390 infused 0W animals looked no different from saline treated mice, it attenuated quinine + EtOH intake in the 2W animals to the level of 0W animals. Interestingly, DMS-cannulated mice demonstrated similar behavior, with SCH23390 reducing EtOH + quinine consumption, while leaving EtOH consumption undisturbed. Quinine resistance following 2 weeks of free-choice EtOH consumption is attenuated by acute administration of a D1-antagonist in the DLS, suggesting that an alcohol history induces compulsivity and that dopamine contributes to this behavior. This is unique to compulsive drinking, as non-conflicted EtOH drinking was unaffected.