For Manuscript Submission, Check or Review Login please go to Submission Websites List.
For the academic login, please select your country in the dropdown list. You will be redirected to verify your credentials.
Peripheral Effects of Methionine-Enkephalin on Inflammatory Reactions and Behavior in the RatVujić-Redžić V.b · Dimitrijević M.a · Stanojević S.a · Kovačević-Jovanović V.a · Miletić T.a · Radulović J.c
aImmunology Research Center ‘Branislav Janković’, and bInstitute of Chemistry, School of Medicine, Belgrade, Yugoslavia, cDepartment of Molecular Neuroendocrinology, Max Planck Institute for Experimental Medicine, Göttingen, Germany
Methionine-enkephalin (Met-Enk) induces notable alterations in immune and central nervous system functions. The present study was conducted in order to compare peripheral and central effects of Met-Enk on nonspecific immunity, open field behavior and pain perception in the rat. The results showed that 0.2 mg/kg of Met-Enk given intraperitoneally (i.p.) increased concanavalin A (Con-A)-induced paw edema and enhanced basal and phorbol myristate acetate (PMA)-stimulated H2O2 production of peritoneal macrophages. Met-Enk-induced immunopotentiation was antagonized by anti-Met-Enk antibodies (anti-Met-Enk-Ig) and quaternary naltrexone (qNtx). Met-Enk injected i.p. produced an increase of horizontal and vertical locomotor activity in the open field that was reversed by i.p. administration of anti-Met-Enk-Ig and qNtx. The dose of 0.2 mg/kg of Met-Enk applied i.p. did not affect the number of writhes in the test of analgesia. Intracerebroventricular (i.c.v.) injection of Met-Enk, given in a dose that was previously shown to be immunostimulatory, enhanced only basal H2O2 production of peritoneal macrophages, and anti-Met-Enk-Ig antagonized this effect. Besides, i.c.v. treatment with anti-Met-Enk-Ig increased and decreased H2O2 production of peritoneal macrophages under basal and stimulated conditions, respectively. Met-Enk and anti-Met-Enk-Ig injected i.c.v. did not influence activity in the open field and pain sensitivity. Thus, the i.c.v. dose of Met-Enk that was sufficient to modulate immune functions did not influence behavior. It may be concluded that Met-Enk modulated nonspecific immune responses and open field behavior by peripheral mechanisms.
© 2000 S. Karger AG, Basel