Opioid modulation of ingestive behaviors in woodchucks and racoons

S. E. Nizielski, J. E. Morley, B. A. Gosnell, U. S. Seal, A. S. Levine

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We have examined the effect on feeding of opioid blockade with naloxone in two species which demonstrate a marked seasonality in their feeding patterns, the racoon (Procyon lotor) and the woodchuck (Marmota monax). Naloxone suppressed food intake in the woodchuck which is a true hibernator. Naloxone failed to suppress food intake in the racoon and, in fact, enhanced intake of a preferred sucrose solution. In the racoon, ir-dynorphine concentrations were extremely high in the hypothalamus compared to the values obtained in rats and woodchucks. We suggest that possible explanations for the lack of responsiveness to opiates in racoons may be (1) their extremely high daily food intake relatively to body mass when compared to woodchucks and rats and (2) the high levels of ir-dynorphin may be sufficient to overcome the inhibitory effect of naloxone. These studies stress the occurrence of species diversity in the response to opioid antagonism.

Original languageEnglish (US)
Pages (from-to)171-176
Number of pages6
JournalPhysiology and Behavior
Issue number2
StatePublished - Feb 1985
Externally publishedYes


  • Food intake
  • Naloxone
  • Opioids
  • Racoons
  • Woodchucks


Dive into the research topics of 'Opioid modulation of ingestive behaviors in woodchucks and racoons'. Together they form a unique fingerprint.

Cite this