title: Effect of morphine on the neuropathogenesis of SIVmac infection in Indian Rhesus Macaques.
abstract: Morphine is known to prevent the development of cell-mediated immune (CMI) responses and enhance expression of the CCR5 receptor in monocyte macrophages. We undertook a study to determine the effect of morphine on the neuropathogenesis and immunopathogenesis of simian immunodeficiency virus (SIV) infection in Indian Rhesus Macaques. Hypothetically, the effect of morphine would be to prevent the development of CMI responses to SIV and to enhance the infection in macrophages. Sixteen Rhesus Macaques were divided into three experimental groups: M (morphine only, n = 5), VM (morphine + SIV, n = 6), and V (SIV only, n = 5). Animals in groups M and VM were given 2.5 mg/kg of morphine sulfate, four times daily, for up to 59 weeks. Groups VM and V were inoculated with SIVmacR71/17E 26 weeks after the beginning of morphine administration. Morphine prevented the development of enzyme-linked immunosorbent spot-forming cell CMI responses in contrast to virus control animals, all of which developed CMI. Whereas morphine treatment had no effect on viremia, cerebrospinal fluid viral titers or survival over the time course of the study, the drug was associated with a tendency for greater build-up of virus in the brains of infected animals. Histopathological changes in the brains of animals that developed disease were of a demyelinating type in the VM animals compared to an encephalitic type in the V animals. This difference may have been associated with the immunosuppressive effect of the drug in inhibiting CMI responses.
authors.affiliation: Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Mail Stop 3043, 3901 Rainbow Blvd., Kansas City, KS 66160, USA.
authors.forename: Joanne K
authors.initials: JK
authors.lastname: Marcario
authors.forename: Mariam
authors.initials: M
authors.lastname: Riazi
authors.forename: Istvan
authors.initials: I
authors.lastname: Adany
authors.forename: Himanshu
authors.initials: H
authors.lastname: Kenjale
authors.forename: Kandace
authors.initials: K
authors.lastname: Fleming
authors.forename: Janet
authors.initials: J
authors.lastname: Marquis
authors.forename: Olga
authors.initials: O
authors.lastname: Nemon
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Mayo
authors.forename: Thomas
authors.initials: T
authors.lastname: Yankee
authors.forename: Opendra
authors.initials: O
authors.lastname: Narayan
authors.forename: Paul D
authors.initials: PD
authors.lastname: Cheney
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000473:pathology / Q000821:virology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002452:Cell Count; D005434:Flow Cytometry; D007111:Immunity, Cellular / Q000187:drug effects*; D008253:Macaca mulatta; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D012367:RNA, Viral / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000473:pathology / Q000821:virology*; D015302:Simian Immunodeficiency Virus / Q000187:drug effects / Q000276:immunology; D019562:Viral Load; D014766:Viremia / Q000188:drug therapy
chemical_list: D009294:Narcotics; D012333:RNA, Messenger; D012367:RNA, Viral; D009020:Morphine