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.
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200031, China.
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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