Synthesis of optically active TAN-67, a highly selective delta opioid receptor agonist, and investigation of its pharmacological properties.

We have synthesized the nonpeptidic highly selective delta opioid receptor agonist, (+/-)-TAN-67, (4aS*, 12aR*)-4a-(3-hydroxyphenyl)-2-methyl-1,2,3,4,4a,5,12,12a-octahydropyrido [3,4-b] acridine. In spite of high potent agonist activity for the delta opioid receptor in in vitro assay, (+/-)-TAN-67 afforded no analgesic activity in the mouse warm-plate test. This result led us to separate (+/-)-TAN-67 into optically pure compounds. Each enantiomer of racemic TAN-67 was synthesized from the corresponding optically active 6-oxodecahydroisoquinoline which was obtained by fractional recrystallization of its optically pure di-p-toluoyl tartaric acid salt. In bioassay using mouse vas deferens, (-)-TAN-67 showed full agonist activity (IC50 = 3.65 nM). On the other hand, (+)-TAN-67 showed almost no agonist activity, but interestingly afforded hyperalgesic activity in vivo (i.t. injection).

Suppression of allograft responses induced by interleukin-6, which selectively modulates interferon-gamma but not interleukin-2 production.

BACKGROUND: Interferon (IFN)-gamma produced by activated T cells represents an important effector cytokine in mediating an inflammatory response. METHODS: The present study investigated the modulation of allograft responses by inhibiting IFN-gamma production. C57BL/6 (B6) lymph node cells were stimulated with class II H2-disparate B6-C-H-2bm12 (bm12) spleen cells. RESULTS: Addition of interleukin (IL)-6 to the primary B6 anti-bm12 mixed lymphocyte reaction (MLR) inhibited neither proliferative responses nor IL-2 production. However, IL-6 induced a dose-dependent suppression of IFN-gamma production in the same MLR cultures. B6 mice were engrafted with bm12 skin grafts, and IL-6 was given to bm12 skin graft recipients every other day. T cells from these recipient mice produced significantly less IFN-gamma in secondary B6 anti-bm12 MLR than those from bm12 skin graft recipients that had not received IL-6 injections. IFN-gamma production by these T cells was suppressed more strongly when the secondary MLR was conducted in the presence of IL-6. In addition to suppression of IFN-gamma expression, IL-6 injections resulted in prolongation of bm12 skin graft survival. The critical involvement of IFN-gamma in anti-bm12 rejection responses was substantiated by evidence that administration of anti-IFN-gamma monoclonal antibody strikingly prolonged bm12 skin graft survival. The prolongation of graft survival by in vivo treatment with either IL-6 or anti-IFN-gamma monoclonal antibody was found to be induced without blocking cellular infiltration of the grafts. CONCLUSIONS: These results indicate that IFN-gamma acts as a key cytokine in a B6 anti-bm12 allograft response and that IL-6 may down-regulate this response by inhibiting IFN-gamma production of alloreactive T cells.