Localization of monoamine fluorescence in the Caiman sclerops



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This investigation used the Falck-Hillarp histochemical fluorescence technique to locate and map monoamine compounds in the brain of the spectacled caiman, Caiman sclerops. This method which has been used to differentiate between catecholamines and serotonin on the basis of color in a number of animal species was found to work well on the crocodilian brain. The fluorescent cells have been observed to be connected with particular structures including substantia nigra to neostriatum, medulla to olfactory bulb and cortex, medulla to spinal cord, and specific hypothalamic connections. Fluorescent cell groups have been located and assigned, numbers in the rat and include Al-4 and Bl-3 in the medulla oblongata, A5-7 and B4-6 in the pons, A8-10 and B7- 9 in the mesencephalon, and All-13 in the diencephalon. Fluorescent cell groups were found in the caiman and sufficiently resembled the groups found in the rat to assign these same identifying numbers to groups of cells in the caiman brain. Additional strong fluorescence was observed in the pyriform cortex, hippocampus and in a region of the posterior diencephalic ependyma. A fluorescent cell group observed in the medulla and not previously reported in the rat was given the number "Ax." Dull fluorescence was observed in the basal ganglia and general cortex.