Neurocircuitry Component - Zorrilla

ABSTRACT Alcohol use disorder (AUD) is a chronic relapsing disorder marked by lasting vulnerability to relapse due to persistent experience of negative emotional protracted abstinence symptoms and related impairments in inhibitory control over alcohol use behavior. Neurobiological understanding of and novel treatments that target these protracted abstinence sequalae are needed to impact AUD relapse. Data from our ARC suggest a novel hypothesis that relapse risk is increased by chronic ethanol-induced imbalance between cortical stress and anti- stress systems in the infralimbic cortex (IL) that impair “top-down” control over the central nucleus of the amygdala (CeA), leading to negative affective dysregulation and compulsive-like, recurrent alcohol use. The Zorrilla Neurocircuitry component, in collaboration with our ARC colleagues, tests this hypothesis in 3 aims. Aim 1 uses retro-DREADD manipulation to test the hypotheses that activity of the IL-CeA projection bidirectionally modifies stress-induced relapse to alcohol-seeking, drinking in risky contexts and in response to frustrative reward omission, and irritability-like behavior. Aim 2 will use systemic and intra-IL brain-site specific administration of translatable small molecule nociceptin opioid peptide (NOP) receptor ligands and a short-acting kappa opioid receptor (KOR) antagonist to test their effects on the increased stress-induced relapse, drinking and irritability of post-dependent CIE rats. Aim 3 uses targeted and unbiased retrograde CAV2-Cre circuit- defined proteomic analysis in STOPflox-MetRS* mice to identify altered expression and post-translational modification of proteins in CeA-projecting IL neurons, by labeling nascent proteins produced during abstinence with the methionine surrogate azido-nor-leucine (ANL). The collaborative studies with each ARC research Component and Core seek to determine the causal role of the IL-CeA projection in stress relapse, drinking and affective dysregulation during protracted abstinence. They also aim to provide translatable insight into the systemic and IL role of KOR and NOP receptor systems with mechanistic neurophysiologic and whole-brain network insight. Finally, they may refine or discover new molecular targets in this key stress-related cortico- amygdalar projection linked to compulsive drinking and AUD relapse under stress and distress.