Dissociating Motivational From Physiological Withdrawal in Alcohol Dependence: Role of Central Amygdala κ-Opioid Receptors

Neuropsychopharmacology. 2016 Jan;41(2):560-7. doi: 10.1038/npp.2015.183. Epub 2015 Jun 24.

Abstract

Chronic intermittent alcohol vapor exposure leads to increased dynorphin (DYN) A-like peptide expression and heightened kappa-opioid receptor (KOR) signaling in the central nucleus of the amygdala (CeA) and these neuroadaptive responses differentiate alcohol-dependent from non-dependent phenotypes. Important for therapeutic development efforts is understanding the nature of the stimulus that drives dependence-like phenotypes such as escalated alcohol self-administration. Accordingly, the present study examined the impact of intra-CeA KOR antagonism on escalated operant alcohol self-administration and physiological withdrawal symptoms during acute withdrawal and protracted abstinence in rats previously exposed to chronic intermittent alcohol vapor. Following operant training, rats were implanted with intra-CeA guide cannula and exposed to long-term intermittent alcohol vapor exposure that resulted in escalated alcohol self-administration and elevated physiological withdrawal signs during acute withdrawal. Animals received intra-CeA infusions of the KOR antagonist nor-binaltorphimine (nor-BNI; 0, 2, 4, or 6 μg) prior to operant alcohol self-administration sessions and physiological withdrawal assessment during acute withdrawal and protracted abstinence. The results indicated that site-specific KOR antagonism in the CeA ameliorated escalated alcohol self-administration during both acute withdrawal and protracted abstinence test sessions, whereas KOR antagonism had no effect on physiological withdrawal scores at either time point. These results dissociate escalated alcohol self-administration from physiological withdrawal symptoms in relation to KOR signaling in the CeA and help clarify the nature of the stimulus that drives escalated alcohol self-administration during acute withdrawal and protracted abstinence.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intranasal
  • Alcoholism / drug therapy
  • Alcoholism / metabolism*
  • Alcoholism / psychology*
  • Animals
  • Central Amygdaloid Nucleus / metabolism*
  • Central Nervous System Depressants / administration & dosage
  • Conditioning, Operant / drug effects
  • Conditioning, Operant / physiology
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Ethanol / administration & dosage
  • Male
  • Motivation / drug effects
  • Motivation / physiology
  • Naltrexone / analogs & derivatives
  • Naltrexone / pharmacology
  • Narcotic Antagonists / pharmacology
  • Rats, Wistar
  • Receptors, Opioid, kappa / antagonists & inhibitors
  • Receptors, Opioid, kappa / metabolism*
  • Self Administration
  • Substance Withdrawal Syndrome / drug therapy
  • Substance Withdrawal Syndrome / metabolism*
  • Substance Withdrawal Syndrome / psychology*

Substances

  • Central Nervous System Depressants
  • Narcotic Antagonists
  • Receptors, Opioid, kappa
  • binaltorphimine
  • Ethanol
  • Naltrexone