Monoamine fluorescence histochemistry of human post mortem brain

Abstract

The distribution of monoamine-containing neuron systems in adult human brains (including a few cases of mental disease) was studied post mortem by Falck-Hillarp fluorescence histochemistry. Endogenous intracellular monoamine stores decreased slowly with time after death, but varicose catecholamine-containing nerve terminals could be demonstrated in many regions several hours after death. A large number of catecholamine (CA), and probably 5-hydroxytryptamine (5-HT) nerve terminals retained an active concentration-dependent uptake mechanism over the terminals retained an active concentration-dependent uptake mechanism over the cell membrane even when the endogenous amines could no longer be visualized. Thus, e.g. the dopamine (DA) nerve terminals of the nucleus caudatus could be clearly visualized by in vitro incubations of caudate slices in Krebs-Ringer buffer containing 10 −6 Mor10 −5 M α-methyl-noradrenaline up to 7 h after death (longest post mortem time studied). A weak CA fluorescence was observed in some perikarya of the large heavily pigmented neurons of the locus coeruleus and more caudally in the pons, as well as in the substantia nigra. More strongly fluorescent CA nerve cell bodies were found in the hypothalamus close to the third ventricle. CA nerve terminals, probably of the NA type were found in the spinal cord and filum terminale, throughout the brain stem, and in other subcortical and cortical areas. 5-HT nerve terminals were less frequently seen but had a similar distribution. Diffuse CA fluorescence, probably of the DA type was clearly observed in sections of the nucleus caudatus and putamen, and in the nucleus amygdaloideus centralis, but not in the globus pallidus. The possibility of applying fluorescence histochemistry to post mortem brain material, especially following in vitro amine incubations means access to an inexhaustible source of material permitting a more detailed mapping of the monoamine neuron systems in adult man and insight into the development of these neuron systems in different human diseases.