It has been shown that spreading depression of the hippocampus can elicit feeding, and that several opioid peptides elicit spreading depression when injected into the hippocampus. To determine whether such depression is the primary mechanism by which opiates induce feeding, we tested the feeding effects of naloxone, an opiate antagonist, and butorphanol tartrate, a kappa-sigma agonist, on feeding in rats with and without hippocampal lesions. Naloxone tended to reduce intake approximately equally in the two groups. Similarly, the doses of butorphanol that increased intake in sham rats were equally effective in lesioned rats. It was concluded that the hippocampus is not the major structure mediating opiate-induced feeding.
Bibliographical noteFunding Information:
We thank Andy Vails for his expert histological assistance. We also thank E. I. DuPont de Nemours and Co., Inc. (Garden City, NY) and Bristol Laboratories (Syracuse, NY) for their generous donations of naloxone and butorphanol tartrate, respectively. This research was supported by the Veterans Administration.
- Butorphanol tartrate