Elsevier

Brain Research

Volume 648, Issue 2, 20 June 1994, Pages 342-346
Brain Research

Sensitization and conditioning of feeding following multiple morphine microinjections into the nucleus accumbens

https://doi.org/10.1016/0006-8993(94)91139-8Get rights and content

Abstract

The effects of repeated morphine infusions (10 μg/0.5 μl) into the nucleus accumbens on feeding were studied in sated rats. As shown previously, intra-accumbens morphine infusions induced a large increase in food intake. After undergoing repeated morphine treatment, animals consumed significant quantities of food in response to a saline or sham injection, compared to their pre-morphine baseline. This conditioned feeding was present up to 18 days after the final drug infusion. Additionally, repeated morphine administration caused a progressive sensitization of feeding; the final morphine infusion elicited nearly double the amount of food intake as the first. Multiple saline infusions had no behavioral effects. Repeated stimulation of opiate receptors may enhance associative mechanisms such that previously neutral environmental stimuli acquire the ability to elicit feeding. Abnormal activation of this system may be a possible neural substrate for compulsive feeding and bulimia.

References (33)

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This work was supported in part by Grant DA04788 from the National Institute on Drug Abuse.

1

Present address: Dept. Neurosciences, University of California at San Diego, La Jolla, CA 92037, USA.

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