Decreased inflammatory pain due to reduced carrageenan-induced inflammation in mice lacking adenosine A3 receptors.
Mice with a targeted disruption of adenosine A(3) receptor (A(3)AR) gene were assessed for their nociceptive threshold and for their localized inflammatory response following carrageenan injected into the hindpaw. Under basal conditions no difference was seen between A(3)AR knock-out (A(3)AR(-/-)) and wild-type (A(3)AR(+/+)) mice in nociceptive response to mechanical or heat stimuli. The antinociceptive response to the intrathecal adenosine analogue R-phenylisopropyl adenosine (R-PIA) was also unchanged in the A(3)AR(-/-) mice. In contrast, heat hyperalgesia, plasma extravasation and edema following carrageenan-induced inflammation in the hind paw were significantly reduced in A(3)AR(-/-) mice compared to the A(3)AR(+/+) controls. Thus, mice lacking A(3)AR had deficits in generating the localized inflammatory response to carrageenan, supporting a pro-inflammatory role of A(3)AR in peripheral tissues. However, no evidence for a role of A(3)AR in nociception and the antinociceptive effect of R-PIA was found.
Wu
W-P
WP
Department of Medical Laboratory Sciences and Technology, Division of Clinical Neurophysiology, Huddinge University Hospital, Karolinska Institutet, S-141 86 Huddinge, Sweden.
Hao
J-X
JX
Halldner-Henriksson
L
L
Xu
X-J
XJ
Jacobson
M A
MA
Wiesenfeld-Hallin
Z
Z
Fredholm
B B
BB
D000818:Animals; D002351:Carrageenan / Q000009:adverse effects*; D007249:Inflammation / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010146:Pain / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology*; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1 / Q000172:deficiency* / Q000235:genetics
D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1; D002351:Carrageenan