- Email: [email protected]
S100 immunoreactivity in a subpopulation of oligodendrocytes and Ranvier's nodes of adult rat brain
Neuroscience Letters 186 (1995) 13-16
S 100 immunoreactivity in a subpopulation of oligodendrocytes Ranvier’s nodes of adult rat brain
and
Michael Rickmann*, Joachim R. Wolff Department of Anatomy, University of GBttingen, Kreuzbergring 36, D-37075 Giittingen, Germany
Received November 7 1994; revised version received December 28 1994; accepted December 28 1994
Abstract The Ca2+- and Zn2+-binding S-100 proteins (S100) are predominantly localized in astrocytes of adult mammalian brain. In addition, light and electron microscopic immunocytochemistry revealed SlOO in a small subpopulation of oligodendrocytes. By nuclear morphology and abundance of rough ER and Golgi fields, these cells resembled actively myelinating oligodendrocytes. SlOO immunoreactivity was also found in paranodal loops and outer mesaxons of isolated of myelin sheaths. Data suggests that oligodendroglial content of SlOO relates to cell turnover and/or myelin repair in the adult rat brain, and that SlOO is present during myelin compaction. Keywords:
Rat; Adult central nervous system; Immunohistochemistry; Oligodendrocytes; Myelin; S 100 protein
S-100 proteins (SlOO) are Ca2+- and Zn2+-binding proteins, which exist at high concentrations in mammalian brains [ 131. SlOOa (subunit composition a/?) and especially SlOOb @#I) are considered to be multifunctional proteins with intra- and extracellular Ca2+-dependent actions (for review, see Ref. [3]). S-100 proteins are cytosolic, but more than 10% of them are bound to membranes. SlOO is commonly regarded to be predominantly located in glial cells, especially in those of the astroglial lineage [.5,20], although certain subpopulations of neurons may also contain SlOO in submammalian vertebrates [6] as well as in mammals [ 161. In contrast to the regular expression of SlOO in astrocytes, reports on SlOO localization in myelin-forming glial cells are still controversial. In the peripheral nervous system, many Schwann cells safely identified by morphological criteria apparently contain SlOO. In dorsal root ganglia, SlOO immunoreactivity was found in perikarya of Schwann cells, while myelin sheaths appeared SlOO negative [ 191. Mata et al. [ 121 suggested that myelinforming Schwann cells express more SlOO than nonmyelinating cells. In the CNS, immature oligodendrocytes showed SlOO immunoreactivity in the subcortical white xponding author, Tel.: +49 5.51 397063; Fax: +49 551 397995; E-mail: [email protected]. 0304-3940/95/$09.50 SSDI 0304-3940(95)
matter of cats during postnatal development [4], while in adult rat brain, Ludwin et al. [ 1 l] found immunoreactivity for SlOO only in isolated cells, which did not react with GFAP antibodies and resembled oligodendrocytes. In contrast, Rodriguez et al. [ 181 referred to an antiserum against SlOO that preferentially stained oligodendroglial cells. In all these cases, S-100 positive oligodendrocytes were mainly identified by morphological criteria at light microscopic level. In the course of studies on the distribution of S-100 proteins in rat brain [ 151, the oligodendroglial localization of this antigen was investigated. This study utilized light and electron microscopic immunocytochemical techniques and focused on the parieto-occipital cortex, its subcortical white matter and the lateral superior olive. Female rats ranging from 120 to 180 days of age were deeply anesthetized with ether and transcardially perfused with a fixative containing 4% paraformaldehyde, 0.3% glutaraldehyde and 0.1% CaC12 in 0.1 M sodium cacodylate buffer (pH 7.3). Vibratome sections (50pm thick) were incubated with a polyclonal antiserum (DAKO, diluted at 1:lOOO or 1:2000), monoclonal G12BS antibody ([7]; ascites fluid diluted at 1:lOOO) or SH-Bl antibody, specific for SloqS (Sigma, diluted at 1: 1000). Immunohistochemical detection was done as previously described [ 171, using the ABC technique and peroxidase histochem-
0 1995 Elsevier Science Ireland Ltd. All rights reserved
11269-Y
M. Rickmann, J.R. Wolff1 Neuroscience Letters I86 (1995) 13-16
y with heavy metal intensification according to Adams . Sections were either directly studied by light micros)y or postfixed with OsO,+ flat embedded in epoxy in, resectioned at 1.5 pm-thickness and counterstained h methylene blue-azur II before microscopic anal) sis. nrficially located semithin sections showed optimal ibody penetration and served for light microscopic ssification of cells based on nuclear and cytoplasmic rphology [lo]. For electron microscopy, ultrathin secis were prepared by resectioning semithin sections :cted for full complement of SlOO staining. Optimal ibody penetration was assumed when numerous, insely stained astroglial processes were seen, while ning was only diminished in astroglial lamellae thinthan 50 nm. Electron microscopic investigation of the lateral supe* olive revealed SlOO immunoreactivity in a few myesheaths (Fig. lA, B). Accordingly, in some cross secIS through myelinated axons, the innermost pocket of elin sheaths showed SlOO staining where it contained re cytoplasm (Fig. 1C). The compacted part of the elin sheaths was always SlOO negative. In longitudily sectioned nerve fibers, SlOO immunoreactivity was ricted to the cytosol enclosed in the loops of myelin aths near Ranvier’s nodes (Fig. lA,B). The staining :nsity was similar to that of astroglial processes and lellae located nearby. We also investigated extensively white matter and lamina VI of the neocortex. In this ation, however, we did not find SlOO containing myelamellae. in addition to SlOO staining in myelin lamellae, a few lerately S 100 immunoreactive cells were found which jlayed characteristic features of oligodendroglial cells ;. lD,E). They showed substantial amounts of periyal cytoplasm, extended Golgi fields and numerous rt profiles of rough ER (Fig. 1F). Their processes ned gap junction-like contacts with astroglial proc:s (Fig. lF,H). Such contacts have been described to ur between astrocytes and oligodendrocytes [14] but between glial cells and neurons. Furthermore, weakly Kl positive cell bodies gave rise to processes the ;ma membrane of which sometimes appeared continu-
I: SlOO immunoreactivity
ous with the outer membrane of compacted parts of myelin sheaths (Fig. 1G). In adult rat brain, such S 100 positive oligodendrocytes could be easily overlooked, because they occurred infrequently and were less immunoreactive than astrocytes (Fig. 1E). In counterstained semithin sections containing the neocortical lamina VI and subcortical white matter, we classified SlOO positive and negative glial cells on the basis of nuclear morphology [lo]. Almost all oligodendrocytes appeared SlOO negative, and most SlOO positive cells were astrocytes. However, about 2% (12 out of 512) of the SlOO positive cell bodies showed intermediate structural features. These cells were weakly SlOO immunoreactive and unlike astrocytes sometimes showed a patchy distribution of chromatin with the spoke-wheellike arrangement of typical oligodendrocytes similar to that shown in Fig. 1D. Thus, in adult rat brain, a minor subpopulation of oligodendrocytes is immunoreactive for S-100 proteins. Possibly these cells are somehow related to oligodendroglial cell turnover, i.e. they may correspond to the fraction of cells which are SlOO positive and become carbonic anhydrase-II positive 7 days after cell division [9]. In our material, the SlOO positive oligodendrocytes showed large amounts of rough ER and Golgi cistemae, which are typical features of actively myelinating oligodendrocytes during development and remyelination [2]. The prevalence of SlOO negative oligodendrocytes suggests that they stop synthesizing SlOO at some stage of myelin maturation. This assumption is supported by findings suggesting that SlOOb immunoreactive cells decrease in number during development of the subcortical white matter of cats [4]. Thus, in the adult rat brain, S-100 protein in oligodendrocytes may indicate their involvement in further formation and/or repair of myelin. Despite the absence of SlOO immunoreactivity from cell bodies of mature oligodendrocytes, SlOO was seldom found in cytoplasmic compartments of well differentiated myelin sheaths. Characteristically, staining was always detected only on one side of the respective Ranvier’s node. Thus, SlOO expression was related to one of the myelin units rather than the nodal structure. If SlOO is
in myelin hunellae of the lateral superior olive (A-C) and in oligodendroglial
cell bodies of the neocortex (D-H). (A,B)
Land low magnification views of a longitudinal section through a myelinated axon (a). SloO immunoreactivity is found in pockets of myelin laae (arrow heads) close to one side of the Ranvier’s node. The neighboring astroglial lamellae (star) contacts a capillary (b). In (B) the area shown gher magnification in (A) is framed. Note the absence of SlOO immunoreactivity from the opposing myelin sheath (arrows). SlOO positive dendrite (C) Transverse view of a myelinated axon showing SlOO immunoreactivity only in the innermost myelin pocket (arrow heads). The arrow indii the surface of the vibratome section. (D) Semitbin section of cortical hunina VI: SlOO immunoreactivity is seen in the cytoplasm of an oligodenyte (arrowhead) the nuclear structure of which is visualized by counterstaining with methylene blue-Azur II. (E) View of the subcortical white er in a vibratome section: Note the different intensities of SlOO immunoreactivity in the astrocyte (star) and the presumed oligodendrocyte lwhead). (F) SlOO immunoreactivity is located in the cytosol of an oligodendrocyte (nucleus, o) in deep lamina VI of the parietal cortex. Golgi s (g), mitochondria (m) and numerous profiles of endoplasmic reticulum am spared from staining. Arrowheads, gap junction-like contact; stars, ~ytic processes. (G) The plasma membrane of a SlOO positive oligodendrocyte (nucleus, o) forms the outer mesaxon (arrowhead) of a myelin th. Note the profiles of rough and smooth ER (r, s). The nearby astroglial lamellae (stars) contacts a capillary wall (b). (H) The inset views the gap tion-like contact (arrowheads) between a SlOO positive oligodendrocyte (0) and an astroglial process (stars). Magnification bars: (A,C,G) 0.5pm; 11 pm; (D,E) 5pm; (H) 0.2pm.
M. Rickmann, J.R. Wolff I Neuroscience Letters 186 (1995) 13-16
1.5
16
M. Rickmann. J.R. Wolff1 Neuroscience Letters I86 (1995) 13-16
synthesized by immature oligodendroglial cells, it should become enclosed in the terminal myelin loops during myelin compaction. Apparently, Ranvier’s nodes are sites of myelin turnover in the CNS. Myelin buds off the terminal lamellae and is subsequently degraded by p; dnodal astrocytes [8]. By this mechanism, S 100 would be gradually lost from the myelin sheath after the parent oligodendrocyte stops synthesis. The functional role of S100 proteins during myelination remains to be investigated.
UOI
Ull
WI
u31
111 Adams, J.C., Heavy metal intensificationof DAB-based HRP reaction product, J. Histochem. Cytochem., 29 (1981) 775.
u41
PI Bunge, R.P. and Wood, P., The biology of the oligodendrocyte. In W.T. Norton (Ed.), Oligodendmglia, Advances in Neurochemistry, Vol. 5. Plenum, New York, 1984, pp. l-46. [31- Donate, R., Perspectives in S-100 protein biology, Cell Calcium, 12 (1991) 713-726. 141 Dyck, R.H.. Van Eldik, L.J. and Cynader, MS., Immunohistochemical localization of the S-100 beta protein in postnatal cat vi,sual cortex: spatial and temporal patterns of expression in cortical and subcortical glia, Dev. Brain Res., 72 (1993) 181-192. [51 Ghandour, M.S., Langley, O.K., Labourdette, G., Vincendon, G. and Gombos, G., Specific and artefactual cellular localizations of SlOO protein: an astrocyte marker in rat cerebellum, Dev. Neurosci., 4 (1981) 66-78. WI Goto, S., Matsukado, Y., Uemura, S., Mihara, Y., Inoue, N., Ikeda, J. and Miyamoto, E., A comparative histochemical study of calcineurin and S-100 protein in mammalian and avian brains, Exp. Brain Res., 69 (1988) 645-650. [71 Haan, E., Boss, B.D. and Cowan, W.M., Production and characterization of monoclonal antibodies against the ‘brain specific’ proteins 12-3-2 and S-100, Proc. Natl. Acad. Sci. USA, 79 (1982) 7585-7589. PI Hildebrand, C., Remahl, S., Persson, H. and Bjartmar, C., Myelinated nerve fibres in the CNS, Prog. Neurobiol., 40 (1993) 319384. [91 Kerr, H., Horsmann, C., Schiirmann, M., Delaunoy, J.-P. and Labourdette, G., Problems encountered when immunocytochemistry is used for quantitative glial cell identification in autoradiographic studies of cell proliferation in the brain of the unlesioned adult mouse, Cell Tissue Res., 278 (1994) 85-95.
u51
[W [I71
PSI
[I91
WI
Ling,E.A., Paterson, J.A., Privat, A., Mori, S. and Leblond, C.P., Investigation of glial cells in semithin sections. I. Identification of glial cells in the brain of young rats, J. Comp. Neural., 149 (1973) 43-72. Ludwin, S.K., Kosek, J.C. and Eng, L.F., The topographical distribution of S-100 and GFA proteins in the adult rat brain: an immunohistochemical study using horseradish peroxidase-labelled antibodies, J. Comp. Neural., 165 (1976) 197-208. Mata, M., Alessi, D. and Fink, D.J., SlOO is preferentially distributed in myelin-forming Schwann cells, J. Neurocytol., 19 (1990) 432-442. Matsutani, T., Nagayoshi. M., Tamaru, M., Hirata, Y. and Kate, K.. Changes in the levels of neural cell specific proteins in the developing rat brain, Neurochem. Res., 10 (1985) 1155-l 172. Mugnaini, E., Cell junctions of astrocytes, ependyma, and related cells in the mammalian central nervous system, with emphasis on the hypothesis of a general functional syncytium of supporting cells. In S. Fedoroff and A. Vemadakis (Ms.), Astrocytes, Vol. 1, Academic Press, Orlando, FL, 1986, pp. 329-371. Rickmann, M. and Wolff, J.R., Astroglial (?) SlOO-protein. The dynamics of light and electron microscopic distribution, J. Hiiforsch.. 33 (1992) 117. Rickmann, M. and Wolff, J.R., S-100 protein, expression in subpopulations of neurons of rat brain, Neuroscience, (1995) in press. Rickmann, M. and Wolff, J.R., Modifications in the immunoreactivity patterns of S-100 protein induced by tissue preparation in rat brain, Histochemistty, (1995) in press. Rodriguez, E.M., Rodriguez, S., Schoebitz, K., Yulis, C.R., Hoffmann, P., Manns, V. and Oksche, A., Light- and electronmicroscopic investigation of the rat subcommissural organ grafted under the kidney capsule, with particular reference to immunocytochemistry and lectin histochemistry, Cell Tissue Res., 258 (1989) 499-514. Sugimura, K., Haimoto, H., Nagura, H., Kate. K. and Takahashi, A., Immunohistochemical differential distribution of S-1OOa and S-1oqS in the peripheral nervous system of the rat, Muscle Nerve, 12 (1989) 929-935. Van Eldik, L.J., Ehnmtiied, B. and Jensen, R.A., Production and characterization of monoclonal antibodies with specificity for the SlOO beta polypeptide of brain SlOO fractions, Proc. Natl. Acad. Sci. USA, 81 (1984) 6034-6038.
S 100 immunoreactivity in a subpopulation of oligodendrocytes Ranvier’s nodes of adult rat brain
and
Michael Rickmann*, Joachim R. Wolff Department of Anatomy, University of GBttingen, Kreuzbergring 36, D-37075 Giittingen, Germany
Received November 7 1994; revised version received December 28 1994; accepted December 28 1994
Abstract The Ca2+- and Zn2+-binding S-100 proteins (S100) are predominantly localized in astrocytes of adult mammalian brain. In addition, light and electron microscopic immunocytochemistry revealed SlOO in a small subpopulation of oligodendrocytes. By nuclear morphology and abundance of rough ER and Golgi fields, these cells resembled actively myelinating oligodendrocytes. SlOO immunoreactivity was also found in paranodal loops and outer mesaxons of isolated of myelin sheaths. Data suggests that oligodendroglial content of SlOO relates to cell turnover and/or myelin repair in the adult rat brain, and that SlOO is present during myelin compaction. Keywords:
Rat; Adult central nervous system; Immunohistochemistry; Oligodendrocytes; Myelin; S 100 protein
S-100 proteins (SlOO) are Ca2+- and Zn2+-binding proteins, which exist at high concentrations in mammalian brains [ 131. SlOOa (subunit composition a/?) and especially SlOOb @#I) are considered to be multifunctional proteins with intra- and extracellular Ca2+-dependent actions (for review, see Ref. [3]). S-100 proteins are cytosolic, but more than 10% of them are bound to membranes. SlOO is commonly regarded to be predominantly located in glial cells, especially in those of the astroglial lineage [.5,20], although certain subpopulations of neurons may also contain SlOO in submammalian vertebrates [6] as well as in mammals [ 161. In contrast to the regular expression of SlOO in astrocytes, reports on SlOO localization in myelin-forming glial cells are still controversial. In the peripheral nervous system, many Schwann cells safely identified by morphological criteria apparently contain SlOO. In dorsal root ganglia, SlOO immunoreactivity was found in perikarya of Schwann cells, while myelin sheaths appeared SlOO negative [ 191. Mata et al. [ 121 suggested that myelinforming Schwann cells express more SlOO than nonmyelinating cells. In the CNS, immature oligodendrocytes showed SlOO immunoreactivity in the subcortical white xponding author, Tel.: +49 5.51 397063; Fax: +49 551 397995; E-mail: [email protected]. 0304-3940/95/$09.50 SSDI 0304-3940(95)
matter of cats during postnatal development [4], while in adult rat brain, Ludwin et al. [ 1 l] found immunoreactivity for SlOO only in isolated cells, which did not react with GFAP antibodies and resembled oligodendrocytes. In contrast, Rodriguez et al. [ 181 referred to an antiserum against SlOO that preferentially stained oligodendroglial cells. In all these cases, S-100 positive oligodendrocytes were mainly identified by morphological criteria at light microscopic level. In the course of studies on the distribution of S-100 proteins in rat brain [ 151, the oligodendroglial localization of this antigen was investigated. This study utilized light and electron microscopic immunocytochemical techniques and focused on the parieto-occipital cortex, its subcortical white matter and the lateral superior olive. Female rats ranging from 120 to 180 days of age were deeply anesthetized with ether and transcardially perfused with a fixative containing 4% paraformaldehyde, 0.3% glutaraldehyde and 0.1% CaC12 in 0.1 M sodium cacodylate buffer (pH 7.3). Vibratome sections (50pm thick) were incubated with a polyclonal antiserum (DAKO, diluted at 1:lOOO or 1:2000), monoclonal G12BS antibody ([7]; ascites fluid diluted at 1:lOOO) or SH-Bl antibody, specific for SloqS (Sigma, diluted at 1: 1000). Immunohistochemical detection was done as previously described [ 171, using the ABC technique and peroxidase histochem-
0 1995 Elsevier Science Ireland Ltd. All rights reserved
11269-Y
M. Rickmann, J.R. Wolff1 Neuroscience Letters I86 (1995) 13-16
y with heavy metal intensification according to Adams . Sections were either directly studied by light micros)y or postfixed with OsO,+ flat embedded in epoxy in, resectioned at 1.5 pm-thickness and counterstained h methylene blue-azur II before microscopic anal) sis. nrficially located semithin sections showed optimal ibody penetration and served for light microscopic ssification of cells based on nuclear and cytoplasmic rphology [lo]. For electron microscopy, ultrathin secis were prepared by resectioning semithin sections :cted for full complement of SlOO staining. Optimal ibody penetration was assumed when numerous, insely stained astroglial processes were seen, while ning was only diminished in astroglial lamellae thinthan 50 nm. Electron microscopic investigation of the lateral supe* olive revealed SlOO immunoreactivity in a few myesheaths (Fig. lA, B). Accordingly, in some cross secIS through myelinated axons, the innermost pocket of elin sheaths showed SlOO staining where it contained re cytoplasm (Fig. 1C). The compacted part of the elin sheaths was always SlOO negative. In longitudily sectioned nerve fibers, SlOO immunoreactivity was ricted to the cytosol enclosed in the loops of myelin aths near Ranvier’s nodes (Fig. lA,B). The staining :nsity was similar to that of astroglial processes and lellae located nearby. We also investigated extensively white matter and lamina VI of the neocortex. In this ation, however, we did not find SlOO containing myelamellae. in addition to SlOO staining in myelin lamellae, a few lerately S 100 immunoreactive cells were found which jlayed characteristic features of oligodendroglial cells ;. lD,E). They showed substantial amounts of periyal cytoplasm, extended Golgi fields and numerous rt profiles of rough ER (Fig. 1F). Their processes ned gap junction-like contacts with astroglial proc:s (Fig. lF,H). Such contacts have been described to ur between astrocytes and oligodendrocytes [14] but between glial cells and neurons. Furthermore, weakly Kl positive cell bodies gave rise to processes the ;ma membrane of which sometimes appeared continu-
I: SlOO immunoreactivity
ous with the outer membrane of compacted parts of myelin sheaths (Fig. 1G). In adult rat brain, such S 100 positive oligodendrocytes could be easily overlooked, because they occurred infrequently and were less immunoreactive than astrocytes (Fig. 1E). In counterstained semithin sections containing the neocortical lamina VI and subcortical white matter, we classified SlOO positive and negative glial cells on the basis of nuclear morphology [lo]. Almost all oligodendrocytes appeared SlOO negative, and most SlOO positive cells were astrocytes. However, about 2% (12 out of 512) of the SlOO positive cell bodies showed intermediate structural features. These cells were weakly SlOO immunoreactive and unlike astrocytes sometimes showed a patchy distribution of chromatin with the spoke-wheellike arrangement of typical oligodendrocytes similar to that shown in Fig. 1D. Thus, in adult rat brain, a minor subpopulation of oligodendrocytes is immunoreactive for S-100 proteins. Possibly these cells are somehow related to oligodendroglial cell turnover, i.e. they may correspond to the fraction of cells which are SlOO positive and become carbonic anhydrase-II positive 7 days after cell division [9]. In our material, the SlOO positive oligodendrocytes showed large amounts of rough ER and Golgi cistemae, which are typical features of actively myelinating oligodendrocytes during development and remyelination [2]. The prevalence of SlOO negative oligodendrocytes suggests that they stop synthesizing SlOO at some stage of myelin maturation. This assumption is supported by findings suggesting that SlOOb immunoreactive cells decrease in number during development of the subcortical white matter of cats [4]. Thus, in the adult rat brain, S-100 protein in oligodendrocytes may indicate their involvement in further formation and/or repair of myelin. Despite the absence of SlOO immunoreactivity from cell bodies of mature oligodendrocytes, SlOO was seldom found in cytoplasmic compartments of well differentiated myelin sheaths. Characteristically, staining was always detected only on one side of the respective Ranvier’s node. Thus, SlOO expression was related to one of the myelin units rather than the nodal structure. If SlOO is
in myelin hunellae of the lateral superior olive (A-C) and in oligodendroglial
cell bodies of the neocortex (D-H). (A,B)
Land low magnification views of a longitudinal section through a myelinated axon (a). SloO immunoreactivity is found in pockets of myelin laae (arrow heads) close to one side of the Ranvier’s node. The neighboring astroglial lamellae (star) contacts a capillary (b). In (B) the area shown gher magnification in (A) is framed. Note the absence of SlOO immunoreactivity from the opposing myelin sheath (arrows). SlOO positive dendrite (C) Transverse view of a myelinated axon showing SlOO immunoreactivity only in the innermost myelin pocket (arrow heads). The arrow indii the surface of the vibratome section. (D) Semitbin section of cortical hunina VI: SlOO immunoreactivity is seen in the cytoplasm of an oligodenyte (arrowhead) the nuclear structure of which is visualized by counterstaining with methylene blue-Azur II. (E) View of the subcortical white er in a vibratome section: Note the different intensities of SlOO immunoreactivity in the astrocyte (star) and the presumed oligodendrocyte lwhead). (F) SlOO immunoreactivity is located in the cytosol of an oligodendrocyte (nucleus, o) in deep lamina VI of the parietal cortex. Golgi s (g), mitochondria (m) and numerous profiles of endoplasmic reticulum am spared from staining. Arrowheads, gap junction-like contact; stars, ~ytic processes. (G) The plasma membrane of a SlOO positive oligodendrocyte (nucleus, o) forms the outer mesaxon (arrowhead) of a myelin th. Note the profiles of rough and smooth ER (r, s). The nearby astroglial lamellae (stars) contacts a capillary wall (b). (H) The inset views the gap tion-like contact (arrowheads) between a SlOO positive oligodendrocyte (0) and an astroglial process (stars). Magnification bars: (A,C,G) 0.5pm; 11 pm; (D,E) 5pm; (H) 0.2pm.
M. Rickmann, J.R. Wolff I Neuroscience Letters 186 (1995) 13-16
1.5
16
M. Rickmann. J.R. Wolff1 Neuroscience Letters I86 (1995) 13-16
synthesized by immature oligodendroglial cells, it should become enclosed in the terminal myelin loops during myelin compaction. Apparently, Ranvier’s nodes are sites of myelin turnover in the CNS. Myelin buds off the terminal lamellae and is subsequently degraded by p; dnodal astrocytes [8]. By this mechanism, S 100 would be gradually lost from the myelin sheath after the parent oligodendrocyte stops synthesis. The functional role of S100 proteins during myelination remains to be investigated.
UOI
Ull
WI
u31
111 Adams, J.C., Heavy metal intensificationof DAB-based HRP reaction product, J. Histochem. Cytochem., 29 (1981) 775.
u41
PI Bunge, R.P. and Wood, P., The biology of the oligodendrocyte. In W.T. Norton (Ed.), Oligodendmglia, Advances in Neurochemistry, Vol. 5. Plenum, New York, 1984, pp. l-46. [31- Donate, R., Perspectives in S-100 protein biology, Cell Calcium, 12 (1991) 713-726. 141 Dyck, R.H.. Van Eldik, L.J. and Cynader, MS., Immunohistochemical localization of the S-100 beta protein in postnatal cat vi,sual cortex: spatial and temporal patterns of expression in cortical and subcortical glia, Dev. Brain Res., 72 (1993) 181-192. [51 Ghandour, M.S., Langley, O.K., Labourdette, G., Vincendon, G. and Gombos, G., Specific and artefactual cellular localizations of SlOO protein: an astrocyte marker in rat cerebellum, Dev. Neurosci., 4 (1981) 66-78. WI Goto, S., Matsukado, Y., Uemura, S., Mihara, Y., Inoue, N., Ikeda, J. and Miyamoto, E., A comparative histochemical study of calcineurin and S-100 protein in mammalian and avian brains, Exp. Brain Res., 69 (1988) 645-650. [71 Haan, E., Boss, B.D. and Cowan, W.M., Production and characterization of monoclonal antibodies against the ‘brain specific’ proteins 12-3-2 and S-100, Proc. Natl. Acad. Sci. USA, 79 (1982) 7585-7589. PI Hildebrand, C., Remahl, S., Persson, H. and Bjartmar, C., Myelinated nerve fibres in the CNS, Prog. Neurobiol., 40 (1993) 319384. [91 Kerr, H., Horsmann, C., Schiirmann, M., Delaunoy, J.-P. and Labourdette, G., Problems encountered when immunocytochemistry is used for quantitative glial cell identification in autoradiographic studies of cell proliferation in the brain of the unlesioned adult mouse, Cell Tissue Res., 278 (1994) 85-95.
u51
[W [I71
PSI
[I91
WI
Ling,E.A., Paterson, J.A., Privat, A., Mori, S. and Leblond, C.P., Investigation of glial cells in semithin sections. I. Identification of glial cells in the brain of young rats, J. Comp. Neural., 149 (1973) 43-72. Ludwin, S.K., Kosek, J.C. and Eng, L.F., The topographical distribution of S-100 and GFA proteins in the adult rat brain: an immunohistochemical study using horseradish peroxidase-labelled antibodies, J. Comp. Neural., 165 (1976) 197-208. Mata, M., Alessi, D. and Fink, D.J., SlOO is preferentially distributed in myelin-forming Schwann cells, J. Neurocytol., 19 (1990) 432-442. Matsutani, T., Nagayoshi. M., Tamaru, M., Hirata, Y. and Kate, K.. Changes in the levels of neural cell specific proteins in the developing rat brain, Neurochem. Res., 10 (1985) 1155-l 172. Mugnaini, E., Cell junctions of astrocytes, ependyma, and related cells in the mammalian central nervous system, with emphasis on the hypothesis of a general functional syncytium of supporting cells. In S. Fedoroff and A. Vemadakis (Ms.), Astrocytes, Vol. 1, Academic Press, Orlando, FL, 1986, pp. 329-371. Rickmann, M. and Wolff, J.R., Astroglial (?) SlOO-protein. The dynamics of light and electron microscopic distribution, J. Hiiforsch.. 33 (1992) 117. Rickmann, M. and Wolff, J.R., S-100 protein, expression in subpopulations of neurons of rat brain, Neuroscience, (1995) in press. Rickmann, M. and Wolff, J.R., Modifications in the immunoreactivity patterns of S-100 protein induced by tissue preparation in rat brain, Histochemistty, (1995) in press. Rodriguez, E.M., Rodriguez, S., Schoebitz, K., Yulis, C.R., Hoffmann, P., Manns, V. and Oksche, A., Light- and electronmicroscopic investigation of the rat subcommissural organ grafted under the kidney capsule, with particular reference to immunocytochemistry and lectin histochemistry, Cell Tissue Res., 258 (1989) 499-514. Sugimura, K., Haimoto, H., Nagura, H., Kate. K. and Takahashi, A., Immunohistochemical differential distribution of S-1OOa and S-1oqS in the peripheral nervous system of the rat, Muscle Nerve, 12 (1989) 929-935. Van Eldik, L.J., Ehnmtiied, B. and Jensen, R.A., Production and characterization of monoclonal antibodies with specificity for the SlOO beta polypeptide of brain SlOO fractions, Proc. Natl. Acad. Sci. USA, 81 (1984) 6034-6038.