Astrocytes, not neurons, show most prominent staining for spermidine/spermine-like immunoreactivity in adult rat brain
✍ Scribed by Gregor Laube; Rüdiger W. Veh
- Book ID
- 102655685
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 572 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0894-1491
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✦ Synopsis
Polyamines are involved in a variety of basic cellular functions including proliferation and differentiation. Recent in vitro evidence suggests a role for spermidine or spermine as possible modulators of ionotropic glutamate receptors and inwardly rectifying potassium channels. However, before a functional role of spermidine or spermine in vivo can be considered, the presence of these polyamines in the mammalian central nervous system must be demonstrated. Here we report the localization of spermine/spermidine-like immunoreactivity in the major cell types of the adult rat brain, using polyclonal antibodies raised against glutaraldehyde-conjugated spermine. Neuronal staining was restricted to several discrete brain nuclei and was generally weak. In the hippocampus, immunoreactivity was found in the area of perforant path terminals and in the CA2/CA3 subfields. The CA1 region and the area of the mossy fiber terminals was largely negative. Throughout the brain, the most prominent staining was displayed by astrocytes, as confirmed by comparison with astrocyte and microglial markers, but immunolabel was also detected in oligodendrocytes and pericytes. Their intense staining for spermidine/spermine-like immunoreactivity suggests that astrocytes are the most likely source for extracellular polyamines in the rat brain. GLIA19: 171-179, 1997. r 1997 Wiley-Liss, Inc. The polyamines putrescine (Put), spermidine (Spd), and spermine (Spm) are ubiquitous low molecular weight organic compounds, carrying two, three, or four positive charges, respectively, at physiological pH. In proliferating cells as well as in mature secretory cells, Spd and Spm are present in particularly high (millimolar) cytosolic concentrations (Hougaard, 1992;Tabor and Tabor, 1964). However, the precise molecular mechanisms of the diverse polyamine effects have mostly remained unclear (for reviews, see Ja ¨nne et al.