Contralateral, ipsilateral and bilateral treatments with the kappa-opioid receptor agonist U-50,488H in mononeuropathic rats.
The effect of repeated contralateral administration of the kappa-opioid receptor agonist U-50,488H (trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide methanesulfonate) on nociceptive behaviour was investigated and compared with ipsilateral and bilateral treatments in a rat model of peripheral unilateral neuropathy (chronic constriction of the common sciatic nerve). Administration of 0.3 mg U-50,488H into the contralateral hindpaw on days 6 and 10 after induction of mononeuropathy increased hindpaw withdrawal latency to mechanical but not to thermal stimulation compared to saline-treated rats. No difference in pain-related behaviour was found between different peripheral (contralateral, ipsilateral and bilateral) treatments with 0.3 mg U-50,488H. Autotomy behaviour was reduced for 6 weeks after sciatic nerve ligation in rats treated contralaterally with the opioid receptor agonist. Antinociceptive effects of contralaterally administered U-50,488H were abolished by the peripherally acting opioid receptor antagonist naloxone methiodide. Our findings indicate that contralateral treatment with U-50,488H attenuates nociceptive behaviour in mononeuropathic rats. These antinociceptive effects are mediated via peripheral opioid receptors.
Bileviciute-Ljungar
Indre
I
Department of Physiology and Pharmacology, Karolinska Institutet, S-171 77 Stockholm, Sweden. Indre.Bileviciute@fyfa.ki.se
Spetea
Mariana
M
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000008:administration & dosage / Q000627:therapeutic use*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003251:Constriction, Pathologic; D007839:Functional Laterality / Q000502:physiology; D006358:Hot Temperature; D008297:Male; D010146:Pain / Q000523:psychology; D010523:Peripheral Nervous System Diseases / Q000188:drug therapy* / Q000473:pathology; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000819:agonists*; D012584:Sciatic Nerve / Q000473:pathology; D012652:Self Mutilation / Q000523:psychology
D018712:Analgesics, Non-Narcotic; D017473:Receptors, Opioid, kappa; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer