Suppression of Acute Herpetic Pain-Related Responses by the κ-Opioid Receptor Agonist (-)-17-Cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[N-methyl-3-trans-3-(3-furyl) Acrylamido] Morphinan Hydrochloride (TRK-820) in Mice
(-)-17-Cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[ N -methyl-3- tran s-3-(3-furyl) acrylamido] morphinan hydrochloride (TRK-820) is a κ-opioid receptor agonist that has pharmacological characteristics different from typical κ-opioid receptor agonists. This study was conducted to determine...
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Published in | The Journal of pharmacology and experimental therapeutics Vol. 309; no. 1; p. 36 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
American Society for Pharmacology and Experimental Therapeutics
01.04.2004
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Online Access | Get full text |
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Summary: | (-)-17-Cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[ N -methyl-3- tran s-3-(3-furyl) acrylamido] morphinan hydrochloride (TRK-820) is a κ-opioid receptor agonist that has pharmacological characteristics
different from typical κ-opioid receptor agonists. This study was conducted to determine the antiallodynic and antihyperalgesic
effects of TRK-820 in a mouse model of acute herpetic pain and to compare them with those of the κ-opioid receptor agonist
enadoline and the μ-opioid receptor agonist morphine. Percutaneous inoculation with herpes simplex virus type-1 induced tactile
allodynia and mechanical hyperalgesia in the hind paw on the inoculated side. TRK-820 (0.01â0.1 mg/kg p.o.), enadoline (1â10
mg/kg p.o.) and morphine (5â20 mg/kg p.o.) dose dependently inhibited the allodynia and hyperalgesia, but the antiallodynic
and antihyperalgesic dose of enadoline markedly decreased spontaneous locomotor activity. The antinociceptive action of TRK-820
(0.1 mg/kg) was completely antagonized by pretreatment with norbinaltorphimine, a κ-opioid receptor antagonist, but not by
naltrexone, a μ-opioid receptor antagonist. Repeated treatment with morphine (20 mg/kg, four times) resulted in the reduction
of antiallodynic and antihyperalgesic effects, whereas the inhibitory potency of TRK-820 (0.1 mg/kg) was almost the same even
after the fourth administration. There was no cross-tolerance in antinociceptive activities between TRK-820 and morphine.
Intrathecal and intracerebroventricular, but not intraplantar, injections of TRK-820 (10â100 ng/site) suppressed the allodynia
and hyperalgesia. These results suggest that TRK-820 inhibits acute herpetic pain through κ-opioid receptors in the spinal
and supraspinal levels. TRK-820 may have clinical efficacy in acute herpetic pain with enough safety margins. |
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ISSN: | 0022-3565 1521-0103 |
DOI: | 10.1124/jpet.103.059816 |