Contributions of early life adversity, sex, and traits towards compulsive opioid self-administration

Many people try addictive drugs, but only a small percentage transition from situational/recreational use to the escalating, compulsive, and relapsing disorder of addiction. It is therefore important to characterize the individual differences that render individuals vulnerable to addiction. Substantial evidence suggests that individual differences in early life experience, biological sex, personality traits, and neurobiology of the reward system are all associated with the development of addiction. A dimensional model of how all these factors relate to addiction is necessary, but simultaneously and experimentally probing all these processes in humans is impossible. I therefore conducted a large-scale study to explore these phenomena in rats. Throughout ‘adolescence’ (PND 21-35), I exposed a group of rats to a variety of stressors [i.e., forced-swim, restraint, predator odour, food-restriction, and social isolation; termed ‘early life adversity’ (ELA)]. As adults (PND 60-140), I assessed them on numerous addiction-relevant behavioural traits (i.e., impulsivity, anxiety, novelty-preference, and attraction to reward cues). After trait assessment, I observed the rats’ propensity to self-administer the opiate remifentanil. I then killed a subset of rats and quantified DA receptor mRNA in the mPFC. ELA decreased impulsivity and decreased the rate of acquisition of opiate self-administration in male rats only. Compared to males, female rats exhibited greater anxiety-like behaviour and potentiated opioid self-administration. Anxiety-like behaviour and attraction to reward cues predicted several addiction-relevant behaviours.

Name thesis:degree_name

Master of Science (MSc)

Discipline thesis:degree_discipline

Psychology

Grantor dc:publisher.institution

Graduate Studies

Year dc:date.issued

2017

Author dc:creator

• Hynes, Tristan

Advisor dc:contributor.advisor

• Lovic, Vedran

Committee members dc:contributor.committeemember

• Dyck, Richard
• Antle, Michael
• Borgland, Stephanie

• Psychology--Behavioral

Statement dc:rights

• University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.

Language dc:language.iso

eng

DOI

http://dx.doi.org/10.11575/PRISM/25447

OAI identifier oai:identifier

oai:ucalgary.scholaris.ca:11023/4036