Analgesia produced by intrathecal administration of the kappa opioid agonist, U-50,488H, on formalin-evoked cutaneous pain in the rat.

Abstract

The antinociceptive activity of the selective kappa opioid agonist U-50,488H, given intrathecally (i.t.) against chemically induced cutaneous pain in rats, was assessed from cumulative dose-response experiments and the formalin test. Three successive i.t. doses of 5, 10 and 35 nmol of U-50,488H produced a gradual reduction of pain scores which was statistically significant at all observation periods. This effect was antagonized significantly by 3 mg/kg i.p. of the opiate antagonists, naloxone and WIN 44,441-3. The analgesia profile showed a clear dose-response relationship. A dose producing 50% 'maximum possible analgesia' of 6.20 nmol (95% confidence interval: 3.05-12.59 nmol) was calculated. The results indicated that cutaneous pain of a chemical/inflammatory nature is highly sensitive to activation of kappa receptors of the spinal cord dorsal horn.

• Authors: T Pelissier, C Paeile, R Soto-Moyano, H Saavedra, A Hernández
• Journal: European journal of pharmacology (Eur J Pharmacol) Vol. 190 Issue 3 Pg. 287-93 (Nov 13 1990) ISSN: 0014-2999 [Print] Netherlands
• PMID: 2272367 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Analgesics
• Pyrrolidines
• Formaldehyde
• 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer

Topics

• 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer
• Analgesia
• Analgesics (administration & dosage)
• Animals
• Formaldehyde
• Injections, Spinal
• Male
• Pain (chemically induced, drug therapy)
• Pain Measurement (drug effects)
• Pyrrolidines (administration & dosage)
• Rats
• Skin Diseases (chemically induced, drug therapy)