Biology subjects

Everitt, B. J.

Publications and source records attributed to Everitt, B. J..

2 recordsLinked to original sources

bioRxiv2020

Baclofen decreases compulsive alcohol drinking in rats characterised by reduced levels of GAT-3 in the central amygdala

While most individuals with access to alcohol drink it recreationally, about 5 % lose control over their intake and progressively develop an alcohol use disorder (AUD), characterised by compulsive alcohol drinking accompanied by decreased interest in alternative sources of reinforcement. The neural and molecular mechanisms underlying the vulnerability to switch from controlled to compulsive alcohol intake have not been fully characterized, so limiting the development of new treatments for AUD. It has recently been shown that rats having reduced levels of expression of the gamma-aminobutyric acid (GABA) transporter, GAT-3, in the amygdala tend to persist in seeking and drinking alcohol even when adulterated with quinine, suggesting that pharmacological interventions aimed at restoring GABA homeostasis in these individuals may provide a targeted treatment to limit compulsive alcohol drinking. Here, we tested the hypothesis that the GABAB receptor agonist baclofen, which decreases GABA release, specifically decreases compulsive alcohol drinking in vulnerable individuals. In a large cohort of Sprague-Dawley rats allowed to drink alcohol under an intermittent two-bottle choice procedure, a cluster of individuals was identified that persisted in drinking alcohol despite adulteration or the availability of an alternative ingestive reinforcer, saccharin. In these rats, that were characterised by decreased GAT-3 mRNA levels in the central amygdala, acute baclofen administration (1.5 mg/kg, intraperitoneal) resulted in a decrease in compulsive drinking. These results indicate that low GAT-3 mRNA levels in the central amygdala represent an endophenotype of AUD and that the associated compulsive alcohol drinking characteristic is sensitive to baclofen.

neuroscience↗

bioRxiv2020

The Basolateral amygdala --> Nucleus Accumbens core circuit mediates the conditioned reinforcing effects of cocaine-paired cues on cocaine seeking.

Individuals addicted to cocaine spend much of their time foraging for the drug. Pavlovian drug-associated conditioned stimuli exert a major influence on the initiation and maintenance of drug seeking often long into abstinence, especially when presented response-contingently, acting as conditioned reinforcers that bridge delays to drug use. The acquisition of cue-controlled cocaine seeking has been shown to depend on functional interactions between the basolateral amygdala (BLA) and the core of the nucleus accumbens (NAcC). However, the precise neuronal circuits underlying the acquisition of cue-controlled cocaine seeking behaviour have not been elucidated. Here we used a projection-specific Cre-dependent DREADD-mediated causal approach to test the hypothesis that the direct projections from the BLA to the NAcC are required for the acquisition of cue-controlled cocaine seeking behaviour. In Sprague Dawley rats with cre-mediated expression of the inhibitory DREADD Hm4Di in the NAcC projecting BLA neurons, treatment with CNO, but not vehicle, selectively prevented the impact of cocaine-associated conditioned reinforcement on cocaine seeking under a second-order schedule of reinforcement. This effect was attributable to the chemogenetic inhibition of the NAcC projecting BLA neurons as it was reversible, and absent in CNO-treated rats expressing an empty control virus. In contrast, chemogenetic inhibition of the anterior insula, which receives collateral projections from NAcC projecting BLA neurons, was without effect. These data demonstrate that the acquisition of cue-controlled cocaine seeking that depends on the conditioned reinforcing effects of cocaine cues require activity in the direct projections from the basolateral amygdala to the nucleus accumbens core.

neuroscience↗