Two opposing modes of action of beta-endorphin on lymphocyte function.
Five opioid peptides (alpha-, beta-, and gamma-endorphin, methionine- and leucine-enkephalin) were tested for their effect on the concanavalin A-induced proliferative response of splenocytes of adult male F344 rats. The continuous presence of these opioid peptides during culture of T cells did not affect proliferation. However, 30 min of preincubation with beta-endorphin (beta-end), but not with the other opioid peptides, resulted in a dose-dependent enhancement of proliferation of 50-100%. This potentiating effect of beta-end on proliferation was preceded by an increase in the production of interleukin-2 (IL-2) and in the extent of IL-2 receptor expression. The stimulatory effect of beta-end was not prevented by naloxone, indicating that classical opioid receptors were not involved. The continuous presence of beta-end (or alpha-end) in cultures of cells that had been preincubated with beta-end completely abolished the stimulatory effect, pointing towards the potential of beta-end to regulate T-cell function via different mechanisms.
van den Bergh
P
P
Department of Immunology, TNO-Institute for Aging and Vascular Research, Leiden, The Netherlands.
Rozing
J
J
Nagelkerken
L
L
D000818:Animals; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D004723:Endorphins / Q000276:immunology; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D001615:beta-Endorphin / Q000276:immunology*
D004723:Endorphins; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D001615:beta-Endorphin