title: Small doses of morphine can enhance NK cell cytotoxicity in pigs.
abstract: The effect of small and moderate doses of morphine (MF) on NK cell lytic activity (cytotoxicity, NKCC) ((51)Cr release test) and the number of circulating large granular lymphocytes (LGL) was evaluated in i.v. catheterized Pietrain crossbred pigs. Simultaneously, plasma cortisol (COR) (RIA method) was measured. Blood samples were collected 15, 60, 120, 180, and 240 min after i.v. injections of 0.5, 1.0 and 5.0 mg/kg of MF alone or MF pretreated with naloxone (NX, 1.0 mg/kg, i.v., 15 min before MF). It was found that MF induced dose- and time-dependent changes of NKCC. MF in a dose of 0.5 mg/kg evoked 4-fold increase in NKCC (in comparison to saline) without changes in the number of LGL/NK cells. Higher MF doses (1.0, 5.0 mg/kg) induced an early increase (up to 300Delta% and 29Delta%, respectively) followed by a decrease in cytotoxicity (to -76Delta% after 5.0 mg/kg), and in LGL number (-36Delta% after 5.0 mg/kg). These effects were concomitant with a marked rise in plasma COR (up to 234Delta% after 0.5 mg/kg and 567Delta% after 5.0 mg/kg of MF). NX pretreatment blocked all the changes in cytotoxicity but not in the LGL cell number and COR concentrations. The results indicate that MF, besides having well known immunosuppressive effects, can also enhance NKCC through the opioid receptors-dependent manner. The enhancement of cytotoxicity appears as a purely functional change independent of the recirculation of NK cells which occurs despite the high plasma concentrations of COR.
authors.affiliation: Department of Animal Physiology, University of Gdańsk, ul. Kładki 24, 80-822 Gdańsk, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Borman
authors.forename: Ziemowit
authors.initials: Z
authors.lastname: Ciepielewski
authors.forename: Danuta
authors.initials: D
authors.lastname: Wrona
authors.forename: Wojciech
authors.initials: W
authors.lastname: Stojek
authors.forename: Wojciech
authors.initials: W
authors.lastname: Glac
authors.forename: Emilia
authors.initials: E
authors.lastname: Leszkowicz
authors.forename: Juliusz
authors.initials: J
authors.lastname: Tokarski
mesh_terms: D000818:Animals; D002460:Cell Line; D003602:Cytotoxicity, Immunologic / Q000187:drug effects* / Q000276:immunology; D006098:Granulocytes / Q000187:drug effects / Q000276:immunology; D006854:Hydrocortisone / Q000097:blood; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D013552:Swine
chemical_list: D009270:Naloxone; D009020:Morphine; D006854:Hydrocortisone