Antinociceptive effect of spinally delivered prostaglandin E receptor antagonists in the formalin test on the rat.
The antinociceptive effect of spinally administered prostaglandin E2 receptor antagonists, SC-51089 and SC-51234A, which are selective for EP1 receptors, was examined in rats using the formalin test. Intrathecal injection of SC-51089 (30-300 micrograms) or SC-51234A (30-300 micrograms) resulted in a significant, dose-dependent, suppression of the second phase (10-60 min), but not the first phase (0-9 min), flinching behavior evoked by formalin injection into the paw. ED25 values and 95% confidence intervals for the second phase were 120 (70-200) micrograms for SC-51089 and 80 (50-140) micrograms for SC-51234A. These data demonstrate that specific nociceptive behaviors are attenuated by spinal prostaglandin E2 receptor antagonists and suggest that prostaglandin E2 is involved in facilitated processing at the spinal level.
Malmberg
A B
AB
Department of Anesthesiology, University of California at San Diego, La Jolla 92093-0818.
Rafferty
M F
MF
Yaksh
T L
TL
D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003989:Dibenzoxazepines / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005557:Formaldehyde; D006834:Hydrazines / Q000008:administration & dosage / Q000494:pharmacology; D007278:Injections, Spinal; D008297:Male; D010077:Oxazepines / Q000008:administration & dosage / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018078:Receptors, Prostaglandin E / Q000037:antagonists & inhibitors*; D013116:Spinal Cord / Q000502:physiology*
D000700:Analgesics; D003989:Dibenzoxazepines; D006834:Hydrazines; D010077:Oxazepines; D018078:Receptors, Prostaglandin E; C089526:SC 51234A; C086836:SC 51089; D005557:Formaldehyde