Effects of Kamikihito, a Traditional Chinese Medicine, on Neurotransmitter Receptor Binding in the Aged Rat Brain Determined by in Vitro Autoradiography: Changes in Dopamine D₁and Serotonin 5-HT_2A Receptor Binding

Using in vitro autoradiography, we investigated the effects of Kamikihito (KKT), a traditional Chinese medicine, on specific [³H]SCH23390 binding to dopamine D₁receptors and [³H]ketanserine binding to serotonin 5-HT_2A receptors in the rat brain. Specific binding of both compounds was affected by aging. Long-term administration of KKT resulted in decreases in [³H]SCH23390 binding to the cortex and hippocampus in aged rats, and in decreases in [³H]ketanserine binding to the caudate/putamen in young rats. These results suggest that the changes in dopamine D₁ and serotonin 5-HT_2A receptor binding may be involved in the central effects of KKT.