Tripathi A, Welch S P
Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0613, USA.
Eur J Pharmacol. 1995 May 4;278(1):27-32. doi: 10.1016/0014-2999(95)00091-x.
Antinociceptive activity of intracerebroventricularly administered ketorolac tromethamine was evaluated in mice by measuring inhibition of abdominal stretching induced by p-phenylquinone. Ketorolac tromethamine produced dose-dependent antinociception with an ED50 of 7.34 micrograms/mouse (4.97-10.82) and a maximal effect at 30 micrograms. Selective antagonists of opioid receptors were used to determine ketorolac's mechanism of action. The ketorolac tromethamine-induced antinociception was not blocked by the mu- and delta-opioid receptor antagonists, naloxone and ICI-174,864 (N,N-diallyl-Tyr-Aib-Aib-Phe-Leu), respectively; however, the kappa-opioid receptor antagonist nor-binaltorphimine dihydrochloride significantly blocked this effect. These findings suggest that activation of kappa-opioid receptors appears to play a role in the mechanism of the antinociceptive effect of ketorolac tromethamine. Ketorolac tromethamine may induce the release of endogenous kappa-opioids to produce central nervous system antinociception.
