Modulation of src-kinase attenuates naloxone-precipitated opioid withdrawal syndrome in mice.

This study was designed to investigate the effect of 2,3-dihydro-N, N-dimethyl-2-oxo-3-[(4,5,6,7-tetrahydro-1H-indol-2-yl)methylene]-1H-indole-5-sulfonamide (SU-6656), a selective inhibitor of src family kinase, on the development of naloxone-induced opioid withdrawal syndrome in mice. Subacute morphine administration followed by a single injection of naloxone (8 mg/kg, intraperitoneally) was used to precipitate the opioid withdrawal syndrome in mice. Behavioral observations were made immediately after naloxone treatment. The withdrawal syndrome was quantitatively assessed in terms of withdrawal severity score and frequency of jumping, rearing, forepaw licking, and circling. Daily single administration of SU-6656 was continued during the morphine treatment procedure. Injection of naloxone precipitated severe withdrawal in morphine-dependent mice. However, once-daily administration of SU-6656 (1.5, 3, and 6 mg/kg, intraperitoneally) markedly and dose-dependently attenuated the naloxone-induced morphine withdrawal syndrome. Therefore, it seems that an src family-kinase-linked mechanism is involved in the development of physiological opioid dependence; thus, src family kinase may serve as a potential target to address the pathological condition of physiological dependence and abstinence associated with continuous opioid usage.