Distribution patterns of formaldehyde-induced fluorescence of hypothalamic monoamines.

In a circumscribed area of the preoptic periventricular nucleus of a male rat, formaldehyde-induced monoamine fluorophores modified by treatment with HCl vapors were investigated microfluorometrically (measurement of excitation peak ratio 370 : 320 nm) in all fluorescent terminals and preterminals. Microfluorometric recordings of an individual fluorescent structure were performed without UV irradiation of neighboring fluorophores. Recorded data were sampled and corrected by a microcomputer (Wang PCS II). 19 neuronal processes (axons) contained noradrenaline fluorophores; 11 contained dopamine fluorophores; 6 exhibited uncharacteristic excitation peak ratios; and in 19 recordings technical problems did not allow identification of the fluorophore content.