[The development of cholinesterase activity in the sensitive and motor nuclei of the brain stem in early human embryogenesis].

Distribution of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in nucleus of various formations of embryonic human brain was studied by histochemical method. Early activity of AChE is characteristic for one formations and early BChE activity is shown for others. In fibers of solitarius tract and particularly of descending tract in the V pair of cranial nerves active AChE was revealed for 7-8-week embryos yet. In 10-12-week human foetuses high total AChE and BChE levels were revealed in brain structures. High AChE activity was observed in caudoventrolateral group of the nucleus of the VII pair and the V pair accounting for the integration of reactions of suckling and the transmission of pain impulses towards the higher formations of human brain.