Possible Interaction: Morphine and Tyrosine

“ Morphine and β‐endorphine increased the concentrations of tyrosine and tryptophan, and naloxone decreased the cerebral tryptophan concentration.”

“In addition, morphine treatment induced the expression of suppressor of cytokine signaling protein-1, 2, 3 (SOCS-1, 2, 3) and protein inhibitors of activated STAT-1, 3, X, Y (PIAS-1, 3, X, Y), the key negative regulators of IFN signaling pathway.”

“In addition, morphine inhibited peroxynitrite-induced nitration of tyrosine in a concentration-dependent manner.”

“Furthermore, we show by site-directed mutagenesis that tyrosine (Y382–384) within the P2X7R C-terminus is differentially modulated by repeated morphine treatment and has no bearing on normal P2X7R function.”

“Both morphine and methadone increased the cerebral concentrations of tryptophan and tyrosine and naloxone antagonized these effects.”

“ Morphine also resulted in IRS-1 phosphorylation at serine 612 and reduced tyrosine phosphorylation at the YMXM p85-binding motifs, weakening the association of the IRS-1/p85 phosphatidylinositol 3-kinase complex.”

“Acute administration of morphine (5, 10 and 20 mg/kg) produced dose-dependent increases in blood glucose concentration which were insignificantly potentiated by L-tyrosine (25-200 mg/kg) when given together with morphine.”

“ L-TYR (200 mg/kg) significantly potentiated (P < .05) the analgesic activity of morphine sulfate (10 mg/kg) and codeine sulfate (30 mg/kg).”

“ Morphine , at a concentration of 1 x 10(-5)M increases the incorporation of tritiated tyrosine into dopamine and dihydroxy phenylacetic acid in synaptosomal preparations.”

“ Acute morphine sulfate (50 mg/kg) increased dihydroxyphenylacetic acid/dopamine ratios (DOPAC/DA) (+20%), the conversion of [3H]tyrosine to [3H]dopamine (+73%) and open-field activity (+130%) in CD-1 male mice.”