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Locomotor activity does not predict individual differences in morphine self-administration in rats.
- Source :
-
Pharmacology, biochemistry, and behavior [Pharmacol Biochem Behav] 2018 Mar; Vol. 166, pp. 48-56. Date of Electronic Publication: 2018 Feb 02. - Publication Year :
- 2018
-
Abstract
- Understanding factors contributing to individual differences in opioid addiction vulnerability is essential for developing more effective preventions and treatments. Sensation seeking has been implicated in addiction to several drugs of abuse, yet its relationship with individual differences in opioid addiction vulnerability has not been well established. The primary goal of this study was to evaluate the relationship between locomotor activity in a novel environment, a preclinical model of sensation-seeking, and individual differences in acquisition of i.v. morphine self-administration (SA) in rats. A secondary goal was to evaluate the relationship between activity and elasticity of demand (reinforcing efficacy) for morphine measured using a behavioral economic approach. Following an initial locomotor activity screen, animals were allowed to acquire morphine SA at a unit dose of 0.5 mg/kg/infusion in 4 hour/day sessions (Experiment 1) or 0.2 mg/kg/infusion in 2 hour/day sessions (Experiment 2) until infusion rates were stable. Unit price was subsequently manipulated via progressive reductions in unit dose (Experiment 1) or increases in response requirement per infusion (Experiment 2). Activity levels were not correlated with acquisition of morphine SA in either experiment. Morphine consumption was generally well described by an exponential demand function in both experiments (R <superscript>2</superscript> values > 0.95 for rats as a group), but activity did not correlate with behavioral economic measures. Locomotor activity in a novel environment did not predict individual differences in acquisition of morphine SA. These data complement findings from some human studies and suggest that the role of sensation seeking in individual differences in opioid addiction vulnerability may be limited.<br /> (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Subjects :
- Animals
Behavior, Addictive physiopathology
Dose-Response Relationship, Drug
Locomotion physiology
Male
Predictive Value of Tests
Rats
Rats, Sprague-Dawley
Self Administration
Analgesics, Opioid administration & dosage
Behavior, Addictive diagnosis
Behavior, Addictive psychology
Locomotion drug effects
Morphine administration & dosage
Subjects
Details
- Language :
- English
- ISSN :
- 1873-5177
- Volume :
- 166
- Database :
- MEDLINE
- Journal :
- Pharmacology, biochemistry, and behavior
- Publication Type :
- Academic Journal
- Accession number :
- 29409807
- Full Text :
- https://doi.org/10.1016/j.pbb.2018.01.008