MACROPHAGE-DERIVED NITRIC-OXIDE IS INVOLVED IN THE DEPRESSED CONCANAVALIN-A RESPONSIVENESS OF SPLENIC LYMPHOCYTES FROM RATS ADMINISTERED MORPHINE IN-VIVO
K. Fecho et al., MACROPHAGE-DERIVED NITRIC-OXIDE IS INVOLVED IN THE DEPRESSED CONCANAVALIN-A RESPONSIVENESS OF SPLENIC LYMPHOCYTES FROM RATS ADMINISTERED MORPHINE IN-VIVO, The Journal of immunology, 152(12), 1994, pp. 5845-5852
The present study examined the role of macrophage-derived nitric oxide
in the suppressive effect of in vivo morphine administration on Con A
-stimulated proliferation of splenic lymphocytes in rats. The results
showed that concentrations of nitrite are significantly greater in Con
A-stimulated splenocyte cultures from morphine-treated rats than in c
ultures from saline-treated rats, and that the depletion of macrophage
s from splenocyte cultures abolishes the suppressive effect of morphin
e on Con A-stimulated proliferation. Moreover, the addition of N-G-mon
omethyl-L-arginine (NMMA) to Con A-stimulated splenocyte cultures atte
nuates the suppressive effect of morphine on mitogenic responsiveness.
The addition of excess L-arginine to splenocyte cultures containing N
MMA reverses the effect of NMMA and restores morphine's suppressive ef
fect on Con A-stimulated proliferation, but the addition of D-arginine
to splenocyte cultures containing NMMA does not restore the suppressi
ve effect of morphine. Taken together, these findings demonstrate that
the suppressive effect of in vivo morphine administration on Con A-st
imulated proliferation of splenic lymphocytes involves macrophage-deri
ved nitric oxide.