Regional cerebral glucose utilization during morphine withdrawal in the rat

Regional cerebral glucose utilization was studied by 2-deoxy[14C]glucose autoradiography in morphine-dependent rats and during naloxone-induced morphine withdrawal. In morphine-dependent rats, glucose utilization was increased compared with naive controls uniformly (23-54%) in hippocampus, dentate gyrus, and subiculum and reduced in frontal cortex, striatum, anterior ventral thalamus, and medial habenular nucleus. On precipitation of morphine withdrawal by subcutaneous administration of naloxone at 0.5 mg/kg to morphine-dependent rats, glucose utilization was increased in the central nucleus of amygdala (51%), lateral mammillary nucleus (40%), lateral habenular nucleus (39%), medial mammillary nucleus (35%), and medial septal nucleus (35%) (all, P less than 0.01). Significant increases also occurred in several other limbic structures including interpeduncular nucleus, anterior medial and ventral thalamic nuclei, and lateral septal nucleus. Knowledge of the functional cerebral anatomy of the morphine-withdrawal syndrome should facilitate studies directed toward understanding the molecular mechanisms of opiate withdrawal.