Morphine-withdrawal signs have been induced, in morphine-dependent rats, by microinjection of naloxone in various diencephalic and telencephalic structures. A differential participation of the central amygdala, lateral septum, dorsal hippocampus, medial thalamic nuclei, globus pallidus and caudateputamen has been observed for the following signs: jumping, wet-dog shakes, paw tremor, chewing and diarrhea. Amygdala, medial thalamus and globus pallidus were the most sensitive to local injection of naloxone.