Localization of cholecystokinin immunoreactivity in the human brain with special reference to ontogeny

The cellular localization and regional distribution of peptides of the gastrin/cholecystokinin family was investigated in human fetal, neonatal and adult brains by use of immunohistochemical techniques. It could be revealed that a cholecystokinin-like immunoreactivity is already present in human brain at the 11/12th gestational weeks. With the 19th week a strong increase in number of CCK reactive cells and the reaction intensity is obvious. The data are compared with the distribution pattern of the adult brain. Our data permit to conclude that gastrin/CCK-related material might play roles independent of neurotransmitter functions during early human brain development.