| Abstract: | It is known that in tissue slices treated with dry gaseous formaldehyde according to the histochemical technique of HILLARP & FALCK structures containing catecholamines show a green fluorescence in the fluorescence microscope. The m-hydroxyphenylethylamines m-tyramine, m-hydroxyamphetamine and m-hydroxynorephedrine (metaraminol) enclosed in vitro in dry protein films undergo a similar reaction with dry gaseous formaldehyde and form fluorescent products which have been characterized as 6-hydroxy-3,4-dihydro-isoquinolines existing predominantly in the quinoidal form fluorescing at 385/510 nm. By treatment of these protein layers with gaseous hydrogen chloride another form fluorescing at 360/420 nm can be obtained which is not visible in the fluorescence microscope with the usual equipment. |
