title: Neuropeptide Y Y1 receptors mediate morphine-induced reductions of natural killer cell activity.
abstract: Morphine suppresses a number of immune parameters, such as natural killer (NK) cell activity and lymphocyte proliferation, by acting through mu-opioid receptors in the central nervous system. Prior studies have implicated the sympathetic nervous system in mediating the immunomodulatory effects of acute morphine treatment. However, the peripheral mechanism whereby morphine inhibits NK cell activity is not fully understood. The aim of the present study was to investigate the role of the sympathetic transmitter neuropeptide Y (NPY) in mediating morphine-induced immune alterations. The results showed that administration of the selective NPY Y1 receptor antagonist BIBP3226 blocked morphine's effect on splenic NK activity but did not attenuate the suppression splenocyte proliferative responses to Con-A or LPS. Furthermore, intravenous NPY administration produced a dose-dependent inhibition of splenic NK activity but did not suppress lymphocyte proliferation. Recent studies from our laboratory have demonstrated that morphine modulates NK activity through a central mechanism that requires the activation of dopamine D1 receptors in the nucleus accumbens. Results from the present study showed that microinjection of the D1 receptor agonist SKF-38393 into the nucleus accumbens shell induced a suppression of NK activity that was reversed by BIBP3226. Collectively, these findings demonstrate that NPY Y1 receptors mediate morphine's suppressive effect on NK activity and further suggest that opioid-induced increases in nucleus accumbens D1 receptor activation inhibit splenic NK activity via NPY released from the sympathetic nervous system.
authors.affiliation: Department of Psychology, Davie Hall, CB#3270, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3270, USA. tim@unc.edu
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Saurer
authors.forename: Stephanie G
authors.initials: SG
authors.lastname: Ijames
authors.forename: Donald T
authors.initials: DT
authors.lastname: Lysle
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D004195:Disease Models, Animal; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000276:immunology; D004347:Drug Interactions / Q000502:physiology; D007108:Immune Tolerance / Q000187:drug effects* / Q000276:immunology; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence / Q000150:complications* / Q000276:immunology* / Q000503:physiopathology; D009294:Narcotics / Q000494:pharmacology; D015213:Neuroimmunomodulation / Q000187:drug effects / Q000276:immunology; D009478:Neuropeptide Y / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000276:immunology / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000276:immunology / Q000503:physiopathology
chemical_list: D014151:Anti-Anxiety Agents; C092926:BIBP 3226; D018491:Dopamine Agonists; D009294:Narcotics; D009478:Neuropeptide Y; D017447:Receptors, Dopamine D1; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D009020:Morphine; D001120:Arginine