Lesions of the Nucleus Accumbens in Rats Reduce Opiate Reward but Do Not Alter Context-Specific Opiate Tolerance

• Published in: Behavioral neuroscience Vol. 103; no. 6; pp. 1327 - 1334
• Main Authors: Kelsey, John E, Carlezon, William A, Falls, William A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Psychological Association 01-12-1989
• Subjects: Animal; Animal behavior; Animal Environments; Animals; Arousal - drug effects; Association Learning - drug effects; Behavioral psychophysiology; Biological and medical sciences; Brain; Brain Mapping; Classical Conditioning; Drugs; Fundamental and applied biological sciences. Psychology; Learning - drug effects; Male; Morphine; Morphine - pharmacology; Neural Pathways - drug effects; Nucleus Accumbens; Nucleus Accumbens - drug effects; Preferences; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Inbred Strains; Receptors, Opioid - drug effects; Rodents; Septal Nuclei - drug effects; Social Environment; Tegmentum Mesencephali - drug effects; Operant conditioning; Rat; Rodentia; Central nervous system; Associative relation; Tolerance; Opiates; Basal ganglion; Physical environment; Narcotic analgesic; Nucleus accumbens; Vertebrata; Mammalia; Acquisition process; Preference; Animal; Lesion; Reward
• ISSN: 0735-7044; 1939-0084
• DOI: 10.1037/0735-7044.103.6.1327

Bilateral electrolytic lesions of the nucleus accumbens in rats eliminated the capacity of 10 mg/kg morphine to produce a conditioned place preference (Experiment 1). However, these lesions did not alter the capacity to establish context-specific tolerance to the analgesic effects of 5 mg/kg of morphine (Experiment 2). This latter finding indicates that rats with nucleus accumbens lesions are not impaired in associating the effects of morphine with a particular location. Thus, the failure of morphine to produce a conditioned place preference in these lesioned rats probably cannot be attributed to an inability to associate the effects of morphine with a particular chamber, i.e., the initially nonpreferred chamber. Rather, morphine may fail to establish a conditioned place preference in these rats because nucleus accumbens lesions disrupt a pathway that is critical in mediating the rewarding effects of opiates.