Evidence for mu opioid receptor on mouse spleen lymphocytes.
OBJECTIVE
Using ohmefentanyl (Ohm), a high affinity mu opioid receptor agonist, to find whether mu opioid receptor exists on mouse spleen lymphocytes.


METHODS
The proliferation rates of T-lymphocytes and B-lymphocytes were determined under various concentrations of Ohm with or without naloxone(Nal) in vitro. Binding characteristics of [3H] Ohm with mice spleen lymphocytes were studied by radioligand assays.


RESULTS
Ohm 0.1 pmol.L(-1)-1 nmol.L-1 enhanced Con A-induced spleen T-cell proliferation in vitro. Nal 50 mumol.L-1, which per se enhanced the T-cell proliferation, blocked the enhancing effects of Ohm. However, Ohm had no effect on B-cell proliferation. Furthermore, a satisfactory saturable, specific, and reversible binding was demonstrated with Kd of (6.9 +/- 0.6) nmol.L-1, Bmax of (74 +/- 6) fmol/10(7) cells. The binding of [3H] Ohm was blocked by unlabeled Ohm or Nal.


CONCLUSIONS
Stimulating effects of Ohm on lymphocytes were mediated by opioid receptors. Mouse spleen lymphocytes present mu opioid receptors.
Wu
T
T
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200031, China.
Li
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XY
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D005260:Female; D005283:Fentanyl / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D009270:Naloxone / Q000494:pharmacology; D017450:Receptors, Opioid, mu / Q000819:agonists*; D013154:Spleen / Q000166:cytology*; D013601:T-Lymphocytes / Q000166:cytology*
D017450:Receptors, Opioid, mu; D009270:Naloxone; C037016:F 7302; D005283:Fentanyl