Quaternary Naltrexone Reverses Radiogenic and Morphine-Induced Locomotor Hyperactivity,
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
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The present study attempted to determine the relative role of the peripheral and central nervous system in the production of morphine-induced or radiation-induced locomotor hyperactivity of the mouse. Toward this end, we used a quaternary derivative of an opiate antagonist naltrexone methobromide, which presumably does not cross the blood-brain barrier. Quaternary naltrexone was used to challenge the stereotypic locomotor response observed in these mice after either an i.p. injection of morphine or exposure to 1500 rads 60Co. The quaternary derivative of naltrexone reversed the locomotor hyperactivity normally observed in the C57BL6J mouse after an injection of morphine. It also significantly attenuated radiation-induced locomotion. The data reported here support the hypothesis of endorphin involvement in radiation-induced and radiogenic behaviors. However, these conclusions are contingent upon further research which more fully evaluates naltrexone methobromides capacity to cross the blood-brain barrier.