title: The adenosine agonist N6-R-phenylisopropyladenosine (R-PIA) stimulates feeding in rats.
abstract: Administration of adenosine and agonists of the adenosine receptors to rats results in hypoactivity, hypothermia, muscle relaxation and antinociception. In the present study, we found that the adenosine ligand, N6-R-phenylisopropyladenosine (R-PIA), increased food intake in rats at a time in the day when rats normally eat very little food or none at all. Feeding was not reliably stimulated upon the first exposure to R-PIA, but was clearly increased following repeated administration of this agonist. Other adenosine agonists, namely 2-chloradenosine and 5'N-ethylcarboxamide adenosine, failed to alter feeding after a single injection or after repeated exposure. The adenosine antagonist, caffeine, did not block R-PIA's effect on food intake, whereas the opioid antagonist, naloxone, blocked R-PIA-induced eating. These data suggest that R-PIA stimulates feeding independent of the A1 or A2 adenosine receptors.
authors.affiliation: Neuroendocrine Research Laboratory, VA Medical Center, Minneapolis, MN 55417.
authors.forename: A S
authors.initials: AS
authors.lastname: Levine
authors.forename: M
authors.initials: M
authors.lastname: Grace
authors.forename: D D
authors.initials: DD
authors.lastname: Krahn
authors.forename: C J
authors.initials: CJ
authors.lastname: Billington
mesh_terms: D015762:2-Chloroadenosine; D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D005247:Feeding Behavior / Q000187:drug effects*; D006120:Grooming / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010660:Phenylisopropyladenosine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
chemical_list: D015762:2-Chloroadenosine; D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); D000241:Adenosine