Neurobiology of opioid addiction
2018 (English)Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE credits
Student thesis
Abstract [en]
Since the use of opioids started to emerge for analgesic reasons in the 19th century with the synthetization of morphine, opioids have been studied rigorously to better understand its effects on the brain. This thesis shows that both the analgesic effects and the reinforcing effects of opioids are mediated by the same receptor, the mu opioid receptor (MOR). MOR activity has been correlated to both primary and secondary reinforcers and should be considered to cause positive reinforcement together with increases in dopamine transmission for all drugs of abuse, and not only in relation to opioids. Opioid tolerance, dependence and even addiction are to some extent thought to relate to opioids’ acute effect of cyclic adenosine monophosphate (cAMP) superactivation. Based upon these findings, the allostasis theory of addiction is considered to be the most suitable in defining opioid addiction. The theory claims that the mesolimbic dopamine system becomes sensitized, increasing the attractiveness of opioids. This while counteradaptation increases the pleasurable tolerance of opioids, encouraging the user to increase its intake for the same initial reward. Furthermore the theory claims that cAMP superactivation is causing an unfolding effect of neurobiological and neurochemical expressions which leads to the disorder of addiction. cAMP superactivation is mediating the negatively reinforcing aspects of opioid addiction together with changes to corticotropin-releasing factor (CRF) in the brain stress system, such as the hypothalamic-pituitary-adrenal (HPA) axis and the extended amygdala.
Place, publisher, year, edition, pages
2018. , p. 57
Keywords [en]
Opioids, reinforcement, mu opioid receptor, addiction, allostasis, cAMP
Keywords [sv]
Opioider, belöning, mu opioid receptor, beroende, allostas, cAMP
National Category
Neurosciences
Identifiers
URN: urn:nbn:se:his:diva-15735OAI: oai:DiVA.org:his-15735DiVA, id: diva2:1221508
Subject / course
Cognitive Neuroscience
Educational program
Consciousness Studies - Philosophy and Neuropsychology
Supervisors
Examiners
2018-06-212018-06-202018-06-21Bibliographically approved