The pharmacological stressor yohimbine, but not U50,488, increases responding for conditioned reinforcers paired with ethanol or sucrose.

Autor: Tabbara RI; Section of Biopsychology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada. rayane.tabbara@mail.utoronto.ca.; Department of Psychology, University of Toronto, Toronto, ON, Canada. rayane.tabbara@mail.utoronto.ca., Rahbarnia A; Section of Biopsychology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.; Department of Psychology, University of Toronto, Toronto, ON, Canada., Lê AD; Neurobiology of Alcohol Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada., Fletcher PJ; Section of Biopsychology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.; Department of Psychology, University of Toronto, Toronto, ON, Canada.; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
Jazyk: angličtina
Zdroj: Psychopharmacology [Psychopharmacology (Berl)] 2020 Dec; Vol. 237 (12), pp. 3689-3702. Date of Electronic Publication: 2020 Aug 25.
DOI: 10.1007/s00213-020-05647-0
Abstrakt: Rationale: Environmental stimuli paired with alcohol can function as conditioned reinforcers (CRfs) and trigger relapse to alcohol-seeking. In animal models, pharmacological stressors can enhance alcohol consumption and reinstate alcohol-seeking, but it is unknown whether stress can potentiate the conditioned reinforcing properties of alcohol-paired stimuli.
Objectives: We examined whether the pharmacological stressors, the α-2 adrenoreceptor antagonist yohimbine (vehicle, 1.25, 2.5 mg/kg; IP) and the K-opioid receptor agonist U50,488 (vehicle, 1.25, 2.5 mg/kg; SC), increase responding for conditioned reinforcement, and if their effects interact with the nature of the reward (alcohol vs. sucrose). We subsequently examined the effects of yohimbine (vehicle, 1.25, 2.5 mg/kg; IP) on responding for sensory reinforcement.
Methods: Male Long-Evans underwent Pavlovian conditioning, wherein a tone-light conditioned stimulus (CS) was repeatedly paired with 12% EtOH or 21.7% sucrose. Next, tests of responding for a CRf were conducted. Responding on the CRf lever delivered the CS, whereas responding on the other lever had no consequences. In a separate cohort of rats, the effects of yohimbine on responding just for the sensory reinforcer were examined.
Results: Both doses of yohimbine, but not U50,488, increased responding for conditioned reinforcement. This enhancement occurred independently of the nature of the reward used during Pavlovian conditioning. Yohimbine-enhanced responding for a CRf was reproducible and stable over five tests; it even persisted when the CS was omitted. Both doses of yohimbine also increased responding for sensory reinforcement.
Conclusions: Yohimbine increases operant responding for a variety of sensory and conditioned reinforcers. This enhancement may be independent of its stress-like effects.
Databáze: MEDLINE
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