The adenosine agonist N6-R-phenylisopropyladenosine (R-PIA) stimulates feeding in rats

Allen S. Levine, Martha Grace, Dean D. Krahn, Charles J. Billington

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9 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)280-285
Number of pages6
JournalBrain Research
Issue number1-2
StatePublished - Jan 16 1989


  • Adenosine
  • Caffeine
  • Feeding
  • N-R-phenylisopropyladenosine receptor
  • Naloxone


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