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Differential distribution of spermidine/spermine‐like immunoreactivity in neurons of the adult rat brain
Author(s) -
Laube Gregor,
Bernstein HansGert,
Wolf Gerald,
Veh Rüdiger W.
Publication year - 2002
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.10157
Subject(s) - spermidine , spermine , biology , neuropil , polyamine , kainate receptor , receptor , microbiology and biotechnology , neuroscience , ampa receptor , biochemistry , medicine , glutamate receptor , central nervous system , enzyme
The polyamines spermidine and spermine are small, widely distributed polycations. In the brain, they confer rectification properties upon inwardly rectifying potassium channels and Ca 2+ ‐permeable α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐propionate (AMPA)/kainate receptors and also modify functional properties of N‐methyl‐D‐aspartate receptors. Therefore, functional roles of spermidine/spermine in the adult brain will depend on the colocalization of the spermidine/spermine‐sensitive receptors/channels and the polyamines either in the same or in closely associated cell types. We previously immunocytochemically demonstrated a prominent localization of spermidine/spermine in glial cells, especially astrocytes (Laube and Veh [ 1997] Glia 19:171–179). In contrast to the commonly accepted assumption of a ubiquitous distribution of polyamines in various cell types, in neurons of the rat brain, we detected a highly diverse spermidine/spermine‐like immunoreactivity. The immunoreactivity in neurons and neuropil throughout the rat brain is listed according to intensity in arbitrary groups. The strongest neuronal staining was observed in the hypothalamic paraventricular, supraoptic, and accessory neurosecretory nuclei. Strong cytoplasmic staining was also evident in some motor and somatosensory areas such as the Me5 nucleus of the mesencephalic trigeminal tract, the nucleus ruber, and the large motor neurons of the spinal cord ventral horn. In contrast, in most cortical and hippocampal regions spermidine/spermine‐like immunoreactivity in neurons was relatively weak, whereas in these areas, the labeling pattern was dominated by a diffuse neuropil labeling. In addition to spermidine/spermine immunocytochemistry, ornithine decarboxylase labeling was performed and the resulting labeling patterns were compared. The prominent localization of spermidine/spermine in neurosecretory neurons might point to a functional role different from channel/receptor modification. In these neurons, polyamines might be involved in secretory processes. J. Comp. Neurol. 444:369–386, 2002. © 2002 Wiley‐Liss, Inc.