Modulation of humoral immune response by central administration of leucine-enkephalin: effects of mu, delta and kappa opioid receptor antagonists.
The effect of leucine-enkephalin (Leu-Enk) on primary humoral immune response was investigated following intracerebroventricular (i.c.v.) administration of the peptide in the rat. Leu-Enk stimulated plaque-forming cell (PFC) response in rats i.c.v. injected with 0.1 and 1 micrograms/kg, whereas does of 20 and 50 micrograms/kg exerted immunosuppressive effects. I.c.v. treatment of rats with delta opioid receptor antagonist ICI 174,864 and kappa opioid receptor antagonist nor-binaltorphimine (nor-BNI) blocked stimulation and suppression of PFC response induced by Leu-Enk, respectively. The mu opioid receptor antagonist beta-funaltrexamine (beta-FNA) reversed both immunomodulatory effects produced by Leu-Enk. Since beta-FNA alone had no effect on PFC response (unlike ICI 174,864 and nor-BNI), these data showed that central effects of Leu-Enk on PFC response were mediated by brain mu opioid receptors, and suggested a possible involvement of delta and kappa opioid receptors.
Radulović
J
J
Immunology Research Center Branislav Janković, Belgrade, Yugoslavia.
Mancev
Z
Z
Stanojević
S
S
Vasiljević
T
T
Kovacević-Jovanović
V
V
Pesić
G
G
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D000921:Antibody-Producing Cells / Q000187:drug effects; D001921:Brain / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology*; D006462:Hemolytic Plaque Technique; D007276:Injections, Intraventricular; D008297:Male; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors*; D017473:Receptors, Opioid, kappa / Q000037:antagonists & inhibitors*; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors*
D000276:Adjuvants, Immunologic; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; C051844:norbinaltorphimine; D004743:Enkephalin, Leucine; D009271:Naltrexone; C024524:beta-funaltrexamine; C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine