Effects of morphine and naloxone on proliferation of lymphocytes in vitro.
OBJECTIVE
To study the effects of morphine on different lymphocytes and the influence of naloxone.


METHODS
The proliferation rates of unmature, resting, and activated T-lymphocytes and B-lymphocytes were determined under various concentrations of morphine with or without naloxone in vitro.


RESULTS
Morphine 1 x 10(-10)-1 x 10(-6) mol L-1 enhanced concanavalin A (Con A)-induced splenic T-cell proliferation, and 1 mumol L-1 enhanced lipopolysaccharide (LPS)-induced splenic B-cell proliferation. Naloxone, which per se enhanced the T-cell proliferation, blocked the enhancing effects of morphine. Morphine (1 x 10(-10)-1 x 10(-5) mol L-1) had no influence on the proliferation of resting splenocytes and Con A-induced thymus cells. Morphine 1 mmol L-1 inhibited the proliferation of resting, LPS-induced splenocytes, and Con A-induced splenic and thymus cells. These inhibiting effects were not blocked by naloxone (50 mumol L-1).


CONCLUSIONS
Stimulating effect of morphine on activated T- and B-cells were mediated by opioid receptors and different opioid receptors existed during the differentiation and activation of lymphocytes. The inhibitory effects of morphine (1 mmol L-1) were not mediated by opioid receptors.
Bian
T H
TH
Shanghai Institute of Materia Medica, Chinese Academy of Sciences.
Wang
X F
XF
Li
X Y
XY
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D005260:Female; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008813:Mice, Inbred ICR; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*
D009270:Naloxone; D009020:Morphine