title: Opioid agonist modulation of cytoplasmic free Ca2+ level in concanavalin A-stimulated mouse lymphocytes.
abstract: In this study the influence of mu-, delta-, and kappa-selective opioid agonists (DAMGO, DSLET, and dynorphin A (1-13)) on cytoplasmic free Ca2+ ([Ca2+]i) level in normal and concanavalin-A (Con A)-activated mouse lymphocytes was investigated. [Ca2+]i was measured using the fluorescent dye FURA-2AM. The opioid peptides at 10-12-10-7 M induced some increase in [Ca2+]i in non-activated lymphocytes. However, DAMGO and DSLET (10-13-10-7 M) considerably inhibited a Con A-induced increase in [Ca2+]i. The inhibiting effect of both peptides was higher after 20-min preincubation compare to 2-h preincubation. The effect of the kappa-agonist dynorphin A (1-13) was significantly different depending on the duration of cell pretreatment and the concentration of the peptide used. After preincubation for 20 min at low concentrations (10-12-10-11 M) it slightly stimulated, while at higher (10-10-10-7 M) concentrations it inhibited lymphocyte response to Con A. After preincubation for 2 h, pronounced stimulation of mitogen-induced Ca2+ flux was observed at peptide concentration 10-9 M. The effects of opioids were antagonized by naloxone. These data indicate that functionally active opioid receptors expressed on lymphocytes could be involved in early stages of mitogen activation.
authors.affiliation: Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117871, Russia. dozim@ibch.siobc.ras.ru
authors.forename: I M
authors.initials: IM
authors.lastname: Molotkovskaya
authors.forename: I V
authors.initials: IV
authors.lastname: Malyukova
authors.forename: L A
authors.initials: LA
authors.lastname: Zakharova
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003208:Concanavalin A / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects* / Q000378:metabolism; D004399:Dynorphins / Q000494:pharmacology; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D010446:Peptide Fragments / Q000494:pharmacology; D011957:Receptors, Opioid / Q000819:agonists*
chemical_list: D004745:Enkephalins; D010446:Peptide Fragments; D011957:Receptors, Opioid; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D003208:Concanavalin A; D004743:Enkephalin, Leucine; C026843:dynorphin (1-13); D004399:Dynorphins; C034318:enkephalin, Ser(2), Leu(5), Thr(6)-; D002118:Calcium