Zhou Y, Rubinstein M, Low MJ, Kreek MJ. Hypothalamic-specific proopiomelanocortin deficiency reduces alcohol drinking in male and female mice.
Genes Brain Behav 2017;
16:449-461. [PMID:
27870313 DOI:
10.1111/gbb.12362]
[Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 11/07/2016] [Accepted: 11/16/2016] [Indexed: 01/21/2023]
Abstract
Opioid receptor antagonist naltrexone reduces alcohol consumption and relapse in both humans and rodents. This study investigated whether hypothalamic proopiomelanocortin (POMC) neurons (producing beta-endorphin and melanocortins) play a role in alcohol drinking behaviors. Both male and female mice with targeted deletion of two neuronal Pomc enhancers nPE1 and nPE2 (nPE-/-), resulting in hypothalamic-specific POMC deficiency, were studied in short-access (4-h/day) drinking-in-the-dark (DID, alcohol in one bottle, intermittent access (IA, 24-h cycles of alcohol access every other day, alcohol vs. water in a two-bottle choice) and alcohol deprivation effect (ADE) models. Wild-type nPE+/+ exposed to 1-week DID rapidly established stable alcohol drinking behavior with more intake in females, whereas nPE-/- mice of both sexes had less intake and less preference. Although nPE-/- showed less saccharin intake and preference than nPE+/+, there was no genotype difference in sucrose intake or preference in the DID paradigm. After 3-week IA, nPE+/+ gradually escalated to high alcohol intake and preference, with more intake in females, whereas nPE-/- showed less escalation. Pharmacological blockade of mu-opioid receptors with naltrexone reduced intake in nPE+/+ in a dose-dependent manner, but had blunted effects in nPE-/- of both sexes. When alcohol was presented again after 1-week abstinence from IA, nPE+/+ of both sexes displayed significant increases in alcohol intake (ADE or relapse-like drinking), with more pronounced ADE in females, whereas nPE-/- did not show ADE in either sex. Our results suggest that neuronal POMC is involved in modulation of alcohol 'binge' drinking, escalation and 'relapse', probably via hypothalamic-mediated mechanisms, with sex differences.
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