Involvement of substance P and central opioid receptors in morphine modulation of the CHS response.
Morphine administration prior to challenge with the antigen 2,4-dinitro-fluorobenzene increases the contact hypersensitivity (CHS) response in rats. The present study extended these findings by showing that central, but not systemic, administration of N-methylnaltrexone antagonized the morphine-induced enhancement of the CHS response. The importance of the neuroimmune mediator substance P was shown via the attenuation of the morphine-induced enhancement following both systemic and topical administration of the NK-1 antagonist WIN51,708. Taken together, the findings of the present study provide new data showing that central opioid receptors and peripheral substance P are involved in the morphine-induced enhancement of the CHS response.
Department of Psychology, University of North Carolina, CB#3270 Davie Hall, Chapel Hill, NC 27599, USA. cjnelson@isis.unc.edu
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D000731:Androstanes / Q000008:administration & dosage; D000818:Animals; D001562:Benzimidazoles / Q000008:administration & dosage; D003877:Dermatitis, Contact / Q000276:immunology* / Q000378:metabolism*; D004139:Dinitrofluorobenzene / Q000008:administration & dosage / Q000276:immunology; D004195:Disease Models, Animal; D004333:Drug Administration Routes; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009271:Naltrexone / Q000008:administration & dosage / Q000031:analogs & derivatives; D009292:Narcotic Antagonists / Q000008:administration & dosage; D064729:Neurokinin-1 Receptor Antagonists; D000644:Quaternary Ammonium Compounds; D051381:Rats; D011917:Rats, Inbred Lew; D011957:Receptors, Opioid / Q000378:metabolism*; D013047:Specific Pathogen-Free Organisms; D013373:Substance P / Q000378:metabolism*
D000731:Androstanes; D001562:Benzimidazoles; D009292:Narcotic Antagonists; D064729:Neurokinin-1 Receptor Antagonists; D000644:Quaternary Ammonium Compounds; D011957:Receptors, Opioid; C086111:WIN 51708; C032257:methylnaltrexone; D013373:Substance P; D009271:Naltrexone; D009020:Morphine; D004139:Dinitrofluorobenzene