Dopamine-receptor autoradiography of human narcoleptic brain

Although the pathology of human narcolepsy is unknown, studies of human and canine narcolepsy have suggested that dopamine metabolism may be disturbed. We used quantitative autoradiography to assess dopamine D1- and D2-receptor binding in basal ganglia and amygdala of five narcoleptic and 17 control human brains. In caudate, narcoleptic brains had a statistically significant increase of 57% in D1-receptor binding, and large but not significant increases of 54% in medial globus pallidus D1 binding, 63% in caudate D2-receptor binding, 95% in lateral globus pallidus D2 binding, and 93% in lateral amygdala D2 binding. We found no major changes in the putamen or in the basal or accessory basal nuclei of the amygdala. These results suggest that narcolepsy is associated with upregulation of dopamine receptors in specific areas of the brain, although medications used prior to death may have contributed to the findings.