Measurement of mRNA specific for preprocholecystokinin in rat caudatoputamen and areas projecting to it.

The concentrations of mRNA specific for preprocholecystokinin were measured with a hybridisation procedure after its extraction from rat brain samples. mRNA specific for preprocholecystokinin was not consistently found in the caudatoputamen. In contrast, its concentrations were quite high in the cingulate, subcallosal and parietal cortical areas, which are assumed to send cholecystokinin-containing axons to the caudatoputamen. Also in other areas in which cholecystokinin-pathways to the caudatoputamen may originate, such as the amygdaloid complex, the piriform cortex and the ventral tegmental area/substantia nigra, mRNA specific for preprocholecystokinin could be demonstrated. It is concluded that the caudatoputamen contains no or very few perikarya which synthetize cholecystokinin and that cholecystokinin-peptides which are found in high concentrations in this part of the basal ganglia are located in afferents.