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

Brain Res. 1989 Jan 16;477(1-2):280-5. doi: 10.1016/0006-8993(89)91415-7.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 2-Chloroadenosine
  • Adenosine / analogs & derivatives*
  • Adenosine / pharmacology
  • Adenosine-5'-(N-ethylcarboxamide)
  • Animals
  • Feeding Behavior / drug effects*
  • Grooming / drug effects
  • Male
  • Motor Activity / drug effects
  • Phenylisopropyladenosine / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • Reference Values


  • 2-Chloroadenosine
  • Phenylisopropyladenosine
  • Adenosine-5'-(N-ethylcarboxamide)
  • Adenosine