Lateralization of aminopeptidase A activity in substantia nigra, striatum and frontal cortex of rats

Several brain aminopeptidase activities have been reported to be asymmetric al, but no direct correlation with lateralized functions has been proposed. Cholecystokinin (CCK) coexists with dopamine (DA) in the nigrostriatal sys tem, which is involved in lateralized motor behaviors. Because aminopeptida se A activity is probably responsible for the hydrolysis of CCK, we studied the left-right distribution of glutamate-(GluAP) and aspartate-aminopeptid ase (AspAP) activities in their soluble (Sol) and membrane-bound (M-B) form s in the substantia nigra, striatum and cortex of rats. Although there was a highly significant predominance of the left side in the substantia nigra and striatum for Sol GluAP and M-B AspAP respectively, in the frontal corte x predominance was on the right side for M-B AspAP. These results suggest a relationship between aminopeptidase A activity and lateralized nigro-stria to-cortical functions involving CCK.