[3H]morphine binding is enhanced by IL-1-stimulated thymocyte proliferation.
Mouse thymocytes incubated in vitro with increasing concentrations of interleukin-1 (IL-1) in the presence of phytohemagglutinin (PHA) exhibited a dose-dependent increase in cell proliferation, as measured by [3H]thymidine incorporation. Under these conditions, there was a parallel dose-dependent increase in specific [3H]morphine binding, with a maximum increase of approximately 5-fold over basal levels. The binding sites differ from classical opioid receptors in that they are not stereo-selective. Interleukin-2 was ineffective in promoting either cell proliferation or enhanced opioid binding, but the effects of IL-1 could be mimicked by phorbol myristate acetate (PMA), suggesting the involvement of tyrosine phosphorylation. These results indicate that morphine-binding sites on immune cells can be regulated by cytokine activation.
Roy
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S
Department of Pharmacology, University of Minnesota Medical School, Minneapolis 55455.
Ge
B L
BL
Ramakrishnan
S
S
Lee
N M
NM
Loh
H H
HH
D000818:Animals; D002455:Cell Division; D005246:Feedback; D007375:Interleukin-1 / Q000494:pharmacology*; D008213:Lymphocyte Activation; D051379:Mice; D008813:Mice, Inbred ICR; D009020:Morphine / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011957:Receptors, Opioid / Q000502:physiology; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007375:Interleukin-1; D010835:Phytohemagglutinins; D011957:Receptors, Opioid; D009020:Morphine; D013755:Tetradecanoylphorbol Acetate