The Use of Dark-Field Microscopy for the Visualization of Acetylcholinesterase in Cholinergic Neurons

Acetylcholinesterase (ACEase) was investigated histochemically in hearts, kidneys and urinary bladders of the following animals: man, dog, cat, hamster, rat, tree shrew (Tupaia glis) and lesser bush baby (Galago senegalensis). Slides examined with both bright-field and dark-field illumination showed that use of dark-field microscopy greatly enhanced the visibility of sites of ACEase activity. ACEase-positive nerve fibers which had low enzyme activity were difficult to identify by brght-field, due to their pale staining, but these fibers were easily identified as iridescent structures in the dark-field.