Review of Current Silver Impregnation: Techniques for Histological Examination of Skeletal Muscle Innervation

Abstract

AbstractThe dyes commonly used in histological staining provide little information about the innervation of skeletal muscle because they reveal neither the terminal parts of axons nor the postsynaptic structures of the motor end-plate. Silver methods, which reveal axons of all types, are best applied to thick (50–100μm) frozen sections. The chemical reactions that generate black colloidal silver are well understood, and it is known that with some methods the deposition occurs upon neurofilament proteins in the axons. The reasons for this selectivity are largely unknown. Histochemical staining for acetylcholinesterase activity is the easiest way to display the subneural apparatus of the motor end plate. Though of low specificity, the methods using indigogenic substrates are preferred to those based on hydrolysis of acetylthiocholine. The former techniques can be followed by silver staining, and the blue product of the enzymatic reaction contrasts well with the black axons. Detailed technical instructions a...