Citation

Tollefson S, Himes M, Narendran R. Int. Rev. Psychiatry 2017; 29(6): 567-579.

Affiliation

Department of Radiology , University of Pittsburgh School of Medicine , Pittsburgh , PA , USA.

Copyright

(Copyright © 2017, Informa - Taylor and Francis Group)

DOI

10.1080/09540261.2017.1404445

PMID

29231765

Abstract

Addiction is composed of three phases: intoxication, withdrawal, and craving. Negative reinforcement, strengthening a behaviour by removing an aversive stimulus, has been associated with the withdrawal phase. An imbalance of neurotransmitters within the brain's stress (nociceptin, neuropeptide Y) and anti-stress (CRF, norepinephrine, etc.) system is attributed to negatively reinforced compulsive behaviours associated with relapse. Similarly, post-traumatic stress disorder is characterized by an overactive stress system. In a PTSD mouse model, rodents exhibited impaired cued-fear memory consolidation when nociceptin transmission was blocked. Furthermore, a single-nucleotide polymorphism has been identified between women diagnosed with PTSD and the severity of PTSD symptoms, suggesting a genetic basis. Therefore, it is critical to understand the functions and interactions between the brain's stress and anti-stress neurotransmitters, specifically nociceptin. This paper will examine the hypothalamic-pituitary-adrenocortical axis, evaluate the functions of corticotropin-releasing-factor and nociceptin, discuss nociceptin's role as an anxiolytic or anxiogenic, and discuss PET-imaging studies-all of which targeted nociceptin receptors (NOP-R). Finally, the discussion of pharmacological interventions will be proposed as preventative or therapeutic treatments for those suffering from PTSD and substance-use disorders.

Language: en

Keywords

HPA-axis; NOP-1A; Nociceptin; PET-imaging; addiction; cortiso; post-traumatic stress disorder; radiotracers; stress; substance-use disorder