The central nucleus of the amygdala (CeA) functions as a hub that converts emotionally relevant sensory information into appropriate behavioral and physiological responses, and plays a crucial role in anxiety-like behavior associated with ethanol dependence and withdrawal. Notably, both the corticotropin-releasing factor (CRF) and norepinephrine (NE) systems are critical in behavioral aspects of addiction, including the anxiogenic effects of drug withdrawal. We hypothesize that ethanol dependence induces neuroadaptations in the CeA and that many of these neuroadaptations may persist after cessation of ethanol exposure. Therefore, we propose to investigate whether or not the changes in signal transduction and synaptic functions seen in the CeA persist after prolonged ethanol withdrawal (abstinence) for 1 and 2 weeks. The previous funding period identified critical findings in the understanding of acute alcohol effects and alcohol dependence in the medial subdivision of the CeA. We demonstrated that corticotropin-releasing factor 1 (CRF1) receptors are involved in the ethanol-induced increase in GABA release in CeA and the CRF system is up-regulated after ethanol dependence. Notably, chronic CRF1 antagonist treatment blocked alcohol dependence-induced increases in ethanol consumption. Both the protein kinase C epsilon (PKCepsilon) and adenylate cyclase/protein kinase A (AC/PKA) transduction pathways are involved in mediating the CRF and ethanol effects on GABA release. Ethanol dependence downregulated the GABAB system and gabapentin (a structural analogue of GABA) reversed several behavioral aspects of ethanol dependence. We also identified long-lasting neuroadaptations induced by ethanol dependence in the glutamatergic systems. Based on these combined findings, the research plan of the present competitive renewal will be to continue studying (in vitro and in vivo) the presynaptic mechanisms of ethanol and the neuroadaptations within the CeA during the development of alcohol dependence, with a focus on newly identified intracellular pathways involved in ethanol, CRF and NE effects in the CeA. Since there is no data on the persistence of such neuroadaptive changes after cessation of ethanol exposure, we propose to study neural function during ethanol abstinence and characterize how long those neuroadaptative changes last. The general hypothesis is that chronic ethanol and dependence alter the CRF and NE systems and their effects on CeA GABA and glutamate signaling through common cellular systems to induce a maladaptation in neural function that sensitizes ethanol withdrawal-induced anxiety-like behavior. Given the extreme importance of this observation, it is imperative to provide data that can elucidate the cellular basis of the susceptibility of alcoholics to stress and relapse. A better understanding of the neuroadaptations shaping the synaptic networks involved in ethanol dependence represents a challenge to alcohol researchers and will be useful toward uncovering new therapeutic agents to alleviate alcohol dependence and prevent relapse.

Public Health Relevance

Despite the importance of the corticotropin-releasing factor and norepinephrine systems in behavioral aspects of drug addiction and withdrawal, the neuronal mechanisms involved in their effects in the amygdala have not been fully delineated. Thus, the present competitive renewal will measure the neuroadaptive changes induced by ethanol dependence and withdrawal in these systems in the amygdala. Determining critical neuroadaptions, and their persistence after ethanol exposure, may be invaluable in the development of pharmacotherapeutics for the treatment of alcoholism.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA015566-14
Application #
9390743
Study Section
Neurotoxicology and Alcohol Study Section (NAL)
Program Officer
Liu, Qi-Ying
Project Start
2005-04-01
Project End
2019-07-31
Budget Start
2017-12-01
Budget End
2018-11-30
Support Year
14
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Varodayan, Florence P; Correia, Diego; Kirson, Dean et al. (2017) CRF modulates glutamate transmission in the central amygdala of naïve and ethanol-dependent rats. Neuropharmacology 125:418-428
Logrip, Marian L; Oleata, Christopher; Roberto, Marisa (2017) Sex differences in responses of the basolateral-central amygdala circuit to alcohol, corticosterone and their interaction. Neuropharmacology 114:123-134
Natividad, Luis A; Buczynski, Matthew W; Herman, Melissa A et al. (2017) Constitutive Increases in Amygdalar Corticotropin-Releasing Factor and Fatty Acid Amide Hydrolase Drive an Anxious Phenotype. Biol Psychiatry 82:500-510
Varodayan, Florence P; Bajo, Michal; Soni, Neeraj et al. (2017) Chronic alcohol exposure disrupts CB1 regulation of GABAergic transmission in the rat basolateral amygdala. Addict Biol 22:766-778
Roberto, Marisa; Varodayan, Florence P (2017) Synaptic targets: Chronic alcohol actions. Neuropharmacology 122:85-99
Blasio, Angelo; Wang, Jingyi; Wang, Dan et al. (2017) Novel Small-Molecule Inhibitors of Protein Kinase C Epsilon Reduce Ethanol Consumption in Mice. Biol Psychiatry :
Varodayan, Florence P; de Guglielmo, Giordano; Logrip, Marian L et al. (2017) Alcohol Dependence Disrupts Amygdalar L-Type Voltage-Gated Calcium Channel Mechanisms. J Neurosci 37:4593-4603
Natividad, Luis A; Steinman, Michael Q; Laredo, Sarah A et al. (2017) Phosphorylation of calcium/calmodulin-dependent protein kinase II in the rat dorsal medial prefrontal cortex is associated with alcohol-induced cognitive inflexibility. Addict Biol :
Borghese, Cecilia M; Herman, Melissa; Snell, Lawrence D et al. (2017) Novel Molecule Exhibiting Selective Affinity for GABAA Receptor Subtypes. Sci Rep 7:6230
Kirson, Dean; Oleata, Christopher Shaun; Parsons, Loren Howell et al. (2017) CB1 and ethanol effects on glutamatergic transmission in the central amygdala of male and female msP and Wistar rats. Addict Biol :

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