An experimental study on the sympathetic neuron chains using the fluorescence method for biogenic monoamines.

Since LANGLEY established the "neuron theory" (1921), it has been generally accepted that only one neuron exchange takes place between a cholinergic preand an adrenergic post-ganglionic fiber in the sympathetic ganglia on the way from the lateral horn cells of the thoracolumber part of the spinal cord to the periphery in the sympathetic nervous system. It has been also well known that adrenaline, exactly noradrenaline (v. EULER, 1946), is the transmitter in almost all the sympathetic postganglionic neurons (FELDBERG and GUDDUM, 1934; DALE, 1935). However, monoaminergic nerve terminals (HAMBERGER and NORBERG, 1963, 1965) as well as some monoaminergic interneurons (NORBERG and HAMBERGER, 1964) were microscopically demonstrated by the fluorescence method around and among nerve cells in the inferior mesenteric ganglion of the cat. It is now thought that the arrangement of the neuron chains in the sympathetic nervous system is complicated, and requires further fundamental morphological studies. DAHLSTROM and FUXE (1964), DAHLSTROM (1965, 1967), ERANKO and HARKONEN (1965) already described that the fluorescent material flows from the perikarya to the nerve terminals according to the axoplasmic flow (WEISS and HISCOE, 1948). In the present paper, the author tried to examine the appearance of the fluorescent material, using dogs axotomized at several levels of the nerve course, in order to elucidate the arrangement and the connections of the sympathetic nerve fibers from the spinal cord to the intestinal wall.