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EFFECTS OF DAMGO AND DSLET IN RATS TRAINED TO DISCRIMINATE 22 FROM 2 HOURS FOOD DEPRIVATION
Author(s) -
Jewett David C.,
Kwilasz A.J.,
Wiebelhaus Jason M.,
Stein Lacey J.,
Dunn Adam T.,
Ewan Eric E.,
Tham Rachel L.,
Grace Martha K.,
Levine Allen S.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a680-c
Subject(s) - damgo , endocrinology , medicine , enkephalin , agonist , food intake , μ opioid receptor , stimulus (psychology) , chemistry , meal , psychology , opioid , receptor , psychotherapist
Opioid agonists increase eating under a variety of conditions. We tested the effects of the mu‐ opioid agoinst DAMGO and the delta‐ opioid agonist DSLET in rats trained to discriminate 22 hours food deprivation from 2 hours food deprivation in a two‐lever, operant choice task. After rats acquired the discrimination, subjects were food restricted for 2 hours and responded appropriately. Immediately after the response period, rats were injected in the paraventricular nucleus of the hypothalamus (PVN) with saline (0.5 μl), DAMGO (0.1–3 mol), DSLET (0.1–3 nnol), or neuropeptide Y (NPY; 0.2 nmol). One hour later, the discriminative stimulus effects were assessed. DAMGO and DSLET did not induce discriminative stimulus effects similar to 22 hours food deprivation at doses previously demonstrated to increase eating when food was freely available. As previously demonstrated, NPY induced discriminative stimulus effects similar to those of 22 hours food deprivation. These findings are consistent with hypotheses that 1) in the PVN, mu‐, and delta‐ agonists increase food intake by increasing meal duration rather than initiating eating and 2) NPY administered into the PVN appears to increase food intake by initiating eating. Supported by UW‐Eau Claire Faculty/Student Research Collaboration.