Acetylcholinesterase activity at the synapses of presynaptic boutons with presumed alpha-motoneurons in chicken ventral horn. Light- and electron-microscopic studies.
Acetylcholinesterase (AChE) activity at the synapses of presynaptic boutons on presumed alpha-motoneurons in the chicken ventral horn was studied histochemically at the light- and electron-microscope levels. At the light-microscope level, many dot-like AChE-active sites were observed on the soma and dendrites of presumed alpha-motoneurons. On electron microscopy, reaction products for AChE activity were observed mainly in the synaptic clefts of the four kinds of presynaptic boutons: (1) S type boutons, (2) boutons containing small, spherical, dense cored vesicles (diameter range, 60-105 nm) and spherical, clear vesicles, (3) boutons containing medium-sized, spherical, dense cored vesicles (65-115 nm) and spherical, clear vesicles, and (4) boutons containing large, spherical, dense cored vesicles (80-130 nm) and spherical, clear vesicles. In the light of previous physiological and biochemical studies, the present results suggest the possibility that each of these presynaptic boutons which are AChE-active in their synaptic clefts may contain acetylcholine, substance P, or enkephalins which acts as a neurotransmitter or modulator.
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D006651:Histocytochemistry; D008854:Microscopy, Electron; D009046:Motor Neurons / Q000201:enzymology* / Q000648:ultrastructure; D013116:Spinal Cord / Q000201:enzymology* / Q000648:ultrastructure; D013569:Synapses / Q000145:classification / Q000201:enzymology*
D000110:Acetylcholinesterase