Negative Affect and Excessive Alcohol Intake Incubate during Protracted Withdrawal from Binge-Drinking in Adolescent, But Not Adult, Mice

Abstract

Binge-drinking is common in underage alcohol users, yet we know little regarding the biopsychological impact of binge-drinking during early periods of development. Prior work indicated that adolescent male C57BL6/J mice with a 2-week history of binge-drinking (PND28-41) are resilient to the anxiogenic effects of early alcohol withdrawal. Herein, we employed a comparable Drinking-in-the-Dark model to determine how a prior history of binge-drinking during adolescence (EtOHadolescents) influences emotionality (assayed with the light-dark box, marble burying test, and the forced swim test) and the propensity to consume alcohol in later life, compared to animals without prior drinking experience. For additional comparison, adult mice (EtOHadults) with comparable drinking history (PND56-69) were subdivided into groups tested for anxiety/drinking either on PND70 (24 h withdrawal) or PND98 (28 days withdrawal). Tissue from the nucleus accumbens shell (AcbSh) and central nucleus of the amygdala (CeA) was examined by immunoblotting for changes in the expression of glutamate-related proteins. EtOHadults exhibited some signs of hyperanxiety during early withdrawal (PND70), but not during protracted withdrawal (PND98). In contrast, EtOHadolescents exhibited robust signs of anxiety-l and depressive-like behaviors when tested as adults on PND70. While all alcohol-experienced animals subsequently consumed more alcohol than mice drinking for the first time, alcohol intake was greatest in EtOHadolescents. Independent of drinking age, the manifestation of withdrawal-induced hyperanxiety was accompanied by reduced Homer2b expression within the CeA and increased Group1 mGlu receptor expression within the AcbSh. The present data provide novel evidence that binge-drinking during adolescence produces a state characterized by profound negative affect and excessive alcohol consumption that incubates with the passage of time in withdrawal. These data extend our prior studies on the effects of subchronic binge-drinking during adulthood by demonstrating that the increase in alcoholism-related behaviors and glutamate-related proteins observed in early withdrawal dissipate with the passage of time. Our results to date highlight a critical interaction between the age of binge-drinking onset and the duration of alcohol withdrawal in glutamate-related neuroplasticity within the extended amygdala of relevance to the etiology of psychopathology, including pathological drinking, in later life.

mGlu5-dependent modulation of anxiety during early withdrawal from binge-drinking in adult and adolescent male mice

“…Thus, it would appear from the present results that early alcohol withdrawal produces a right-ward shift in the dose-response function for MTEP-induced anxiolysis − an interpretation consistent with the fact that a prior 2-week history of binge-drinking up-regulates mGlu5 expression within certain extended amygdala structures (Lee et al, 2016, 2017b). Pending replication, these findings may have important ramifications for the therapeutic application of MTEP, or related mGlu5 NAMs, for the treatment of the negative reinforcing properties of alcohol that drive excessive intake.…”

“…A 2-week binge-drinking experience is sufficient to increase anxiety–like behavior in adult mice during early (24 h) alcohol withdrawal across various paradigms, including the FST, light-dark box and marble-burying tests (Lee et al, 2017b; present study) and the manifestation of this hyper-anxious state is associated with elevated mGlu5 expression, at least within the AchSh (Lee et al, 2016). Herein, MTEP pretreatment dose-dependently reduced withdrawal-induced anxiety in adult-onset binge drinkers, as indicated by increased light-side time and entries, reduced marble-burying and increased latency to start burying, as well as increased time spent immobile in the FST.…”

“…Although immobility in the FST is traditionally interpreted as reflecting behavioral despair (Porsolt et al, 1977; Porsolt et al, 2001), alcohol-withdrawn adult mice consistently exhibit reduced immobility in this assay (Lee et al, 2015, 2016, 2017a,b). We demonstrated previously that this behavioral reaction can be reversed by anxiolytic pretreatment (including 3 mg/kg MTEP), arguing that it reflects an anxiety-like response to the swim stressor (Lee et al, 2017a).…”

“…The binge-drinking and behavioral testing procedures employed herein were nearly identical to those used in previous studies in our lab (Lee et al, 2015, 2016, 2017b) and are summarized briefly below. All procedures were conducted in compliance with the National Institutes of Health Guide for Care and Use of Laboratory Animals (NIH Publication No.…”

“…We have shown that adult alcohol-drinking mice exhibit increased behavioral indices of anxiety during early (24 h) withdrawal (Lee et al, 2016). This elevated anxiety coincides with increased expression of metabotropic glutamate receptor 5 (mGlu5) within the nucleus accumbens shell (AcbSh) during acute withdrawal, as indicated by western blotting (Cozzoli et al, 2012; Obara et al, 2009; Lee et al, 2016, 2017b). In contrast, adolescent drinkers were resilient to both withdrawal-induced hyperanxiety and increased mGlu5 expression within the AcbSh during early withdrawal (Lee et al, 2016, 2017b).…”