The metabolic evidence of synergistic interaction between DAMGO and DPDPE on undifferentiated SH-SY5Y cells

Recent studies have demonstrated the analgesic synergy between mu- and delt a -opioid receptor, but evidence obtained at the cellular level is scanty. This work was designed to find the evidence of synergy between the actions of D-Ala(2)-Mephe(4)-glyol(5) enkephalin (DAMGO) and D-Phe(2), D-Phe(5) enk ephalin (DPDPE) on undifferentiated SH-SY5Y cells. Microphysiometer was use d to detect the functional activity of cells by measuring the real-time ext racellular acidification rate (ECAR). The results demonstrate the unequivoc al synergy between DAMGO and DPDPE at least within certain ratios. In addit ion, combined administration of the two drugs in the synergistic ratios att enuates receptor desensitization. These data indicate that DAMGO and DPDPE have a synergistic effect at cellular level. NeuroReport 12:845-849 (C) 200 1 Lippincott Williams & Wilkins.