@article {BJ{\"O}RKLUND525, author = {ANDERS BJ{\"O}RKLUND and BENGT FALCK and ULF STENEVI}, title = {ON THE POSSIBLE EXISTENCE OF A NEW INTRANEURONAL MONOAMINE IN THE SPINAL CORD OF THE RAT}, volume = {175}, number = {2}, pages = {525--532}, year = {1970}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Intraneuronal monoamines have been studied with the histochemical fluorescence method of Falck and Hillarp in the rat spinal cord. The formaldehyde-inducedintrancuronal fluorophores have been analyzed with microspectrofluorometry in combination with drugs which deplete monoamines from the central nervous system. Three types of intraneuronal fluorescence were found. 1) A green fluorescence, with spectra identical with those of the catecholamine fluorophores, which was depleted by reserpine and α-methyl-m-tyrosine but not by p-chlorophenylalanine, was found. This fluorescence was most likely derived from Primary catecholamines. 2) A yellow fluorescence, with spectra identical with those of the 5-hydroxytryptamine fluorophore, which was depleted by reserpine and p-chlorophenylalanine but not by α-methyl-m-tyrosine, was found. This fluorescence was probably derived from 5-hydroxytryptamine. 3) A yellow to brownish-yellow fluorescence, with spectra clearly deviating from those of the catecholamine and the 5-hydroxytryptamine fluorophores, which was depleted by reserpine but not by p-chlorophenylalanine or α-methyl-m-tyrosine, was found. Moreover, this fluorescenceshowed upon ultraviolet irradiation a photodecomposition rate, which was markedly slower than that of the 5-hydroxytryptamine fluorophore. These results strongly indicate that this intraneuronal fluorogenic substance is not identical with a catecholamine or 5-hydroxytryptamine. The spectral characteristics of this third type of fluorescence showed general features characteristic for many indolykthylamines. {\textcopyright} 1970 by The Williams \& Wilkins Co.}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/175/2/525}, eprint = {https://jpet.aspetjournals.org/content/175/2/525.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }