Histochemical observations of fluorescent biogenic amines in cryostat sections of peripheral and central nervous tissue

In our present report we describe a simple histochemical modification of the cryostat technique for demonstrating the catecholamine and serotonin fluorescence in thin sections of peripheral and central nervous tissue. The histochemical fluorescence method of Falck and Hillarp 7 has proven to be a valuable histological tool to study the monoamine localization in central and peripheral nervous tissue. The method shews an extreme sensitivity when the tissue is embedded in Araldite and sectioned down to 1 x of thickness (Hokfelt 0 ). A high degree of specificity is demonstrated by the microspectrophotometric measurements of the several fluorescent compounds of catecholamines and serotonin (Corrodi and Jonsson 1 ). However, the original procedure cannot be practically adapted as a regular histologic technique. Besides others, the main disadvantages are: 1) the freeze-drying is time-consuming; 2) the enzymatic system (cholinergic and MAO-enzyme)