Intrathecal adenosine A1 receptor agonist attenuates hyperalgesia without inhibiting spinal glutamate release in the rat.
The analgesia effects of intrathecal adenosine A1 receptor agonist, R-PIA, on the hyperalgesia and CSF-glutamate release after formalin injection into the rat paw were evaluated. R-PIA significantly and dose-dependently attenuated increases in flinching behavior, and this attenuating effect was reversed by the adenosine A1 receptor antagonist, aminophylline. Morphine blocked flinchs, however MK-801 partially abolished. The increase in CSF-glutamate release evoked by formalin stimulation was inhibited by morphine but not by either R-PIA or MK-801. These findings suggest that the intrathecal adenosine A1 receptor agonist provokes analgesic effect via the postsynaptic action independent of an effect upon spinal glutamate release.
Yamamoto
Syuichiro
S
Department of Laboratory Sciences, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
Nakanishi
Osamu
O
Matsui
Tomohiro
T
Shinohara
Noriyuki
N
Kinoshita
Hiroyuki
H
Lambert
Clinton
C
Ishikawa
Toshizo
T
D000241:Adenosine / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D058907:Adenosine A1 Receptor Agonists; D000818:Animals; D018698:Glutamic Acid / Q000378:metabolism*; D006930:Hyperalgesia / Q000188:drug therapy*; D007278:Injections, Spinal; D008297:Male; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D043682:Receptor, Adenosine A1 / Q000502:physiology; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism
D058907:Adenosine A1 Receptor Agonists; D043682:Receptor, Adenosine A1; C047235:N-(1-methyl-2-phenylethyl)adenosine; D018698:Glutamic Acid; D000241:Adenosine