Me. Hilburger et al., MORPHINE ALTERS MACROPHAGE AND LYMPHOCYTE POPULATIONS IN THE SPLEEN AND PERITONEAL-CAVITY, Journal of neuroimmunology, 80(1-2), 1997, pp. 106-114
We have previously shown that subcutaneous implantation of a 75 mg mor
phine pellet results in suppression of the ability of murine splenocyt
es to mount an antibody response to sheep I ed blood cells, due in par
t to a reduction of macrophage function. The present studies used flow
cytometry to examine whether the decrement in macrophage function in
the spleens of morphine-treated mice results from a reduction in macro
phage numbers. Parallel analysis was carried out on non-elicited perit
oneal cells. In the spleen, morphine resulted in a reduction in the re
lative proportion of macrophages and B-cells, with a concomitant incre
ase in the proportion of T-cells. Alteration in the ratio of CD4(+) to
CD8(+) T-cells was not observed. In contrast, in the peritoneal cavit
y, morphine increased the number of macrophages and reduced the number
of B-cell. Naltrexone blocked all of the chan:es in cellular composit
ion. There results support the conclusion that an important mechanism
in the immunosuppression seen in the spleens of mice implanted with mo
rphine pellets is a differential reduction in the number of macrophage
s and B-cells as compared with T-cells. Further, these studies show th
at subsets of cells of the immune system are differentially affected b
y morphine in different anatomical compartments. (C) 1997 Elsevier Sci
ence B.V.