[Cholinergic neurons in the nuclear formations of the human fetal medulla oblongata]

The medulla oblongata of the human fetuses 22-27-week-old has been studied. Histochemical methods for cholinacetyltransferase (ChAT) and partly for acetylcholinesterase (AChE) have been used. Twenty-five nuclei have been described; four types of neurons with a low, middle, high and very high ChAT activity have been revealed in them. In the motor nuclei, neurons with a high, and in the sensitive nuclei--with a low ChAT activity predominate. In 13 nuclei a relative content of the cholinergic neurons has been calculated; it is low in the lateral reticular nucleus and in the Roller's nucleus (49-53%), high--in nuclei of the cranio-cerebral nerves (92-100%). In the motor neurons of the segmentary centers there is a certain correlation between the ChAT and AChE activity; in other neural centers (the inferior olive, the reticular substance nuclei) there is no such coincidence.