Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Calbindins”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1999

Differential expression of calbindin and calretinin in the human fetal amygdala.

The distribution patterns of the calcium-binding proteins calbindin and calretinin, both expressed early during development within the various amygdaloid nuclei and areas, have been investigated. Anti-calbindin as well as anti-calretinin mark immature, partly migrating neurons in the 5th gestational month; the number of calretinin-immunoreactive neurons is distinctly higher. In the 8th month, calbindin and calretinin are found in a small proportion of presumed pyramidal cells and in various types of non-pyramidal neurons. Small and large bipolar and small and large multipolar neurons are shown to express calbindin and calretinin. Double-labellings show that calbindin and calretinin are largely contained in different subsets of these neuronal types, which are considered to represent interneurons. These nerve cell classes are widespread within the amygdala with mainly moderate to high packing densities. Diffuse immunoreactive structures, which are found in different intensities in the various amygdaloid nuclei, display distinct redistribution during fetal development. The results show that during early fetal development calbindin and particularly calretinin may be involved in the regulation of neuronal migration. In later development, definite subsets of interneurons, which are likely to be functionally different, are marked by anti-calbindin and -calretinin. Different diffuse immunolabelling at various developmental stages probably indicates the sequential arrival of afferent input from brain areas containing calbindin- or calretinin-immunoreactive nerve cells. With the exception that calretinin may be transiently expressed in pyramidal neurons, the distribution of calbindin- and calretinin-immunoreactive structures to a large degree corresponds to that in the adult. Thus, little reorganisation is to be expected during proceeding development.

Amygdala↗
PubMed1990

Immunohistochemical localization of calbindins (28K and 9K) in the tissues of the baboon Papio ursinus.

An indirect immunoperoxidase procedure was used to detect the presence of calbindin-D28K and calbindin-D9K in the cerebellum, kidney, and duodenum of the baboon Papio ursinus. Antibodies to chick calbinding-D28K and to both rat and mouse calbindin-D9K were used. The cerebellum and kidney were shown to contain calbindin-D28K; the doudenum contained calbindin-D9K. In the cerebellum, positive staining was found in the Purkinje cells only; in the kidney, positive staining was found in the distal convoluted tubules, connecting tubules, and collecting tubules, extending deep into the medullary regions of the kidney. Staining in the duodenum was confined to the enterocytes of the villi, with no stain present in the crypt regions or goblet cells. Thus the baboon, a primate, contains the larger of the calbindins in both the cerebellum and kidney as does the human and monkey, but its distribution in the kidney is more generalized than that found in humans. The molecular weight of calbindin-D9K was found to be similar to that found in other animals. However, the calbindin-D28K from the baboon tissues appears to be slightly smaller than the protein found in other animals and may therefore be of similar size to the human calbindin-D28K (Mr 26,000).

Animals↗
PubMed1994

Occurrence and localization of calbindin-D28K in kidney and cerebellum of the slider turtle, Trachemys scripta.

BACKGROUND: Since its initial discovery in the avian intestine, calbindin-D28K has been reported to occur in various species and tissues. Although calbindin-D28K binds calcium ions in the physiologically relevant range of intracellular calcium, its functional role in the various cell types where it has been localized remains unknown. METHODS: We examined the occurrence of calbindin-D28K in the brain and kidney of the testudine reptile, Trachemys scripta, by immunoblotting and immunocytochemistry using rabbit anti-sera directed against rat renal calbindin-D28K and chicken intestinal calbindin-D28K. RESULTS: Immunoblotting revealed the presence of calbindin-D28K in the turtle tissues. A single immunoreactive band in the 28,000 relative molecular mass region was visualized in cerebellar and renal homogenates. Immunocytochemistry revealed reaction product for the presence of calbindin-D28K in the Purkinje cells of the cerebellum, and in the distal tubular cells of the nephron. Processes as well as the perikaryon of the Purkinje cell were immunoreactive. CONCLUSION: This study describes the occurrence and cellular localization of calbindin-D28K in a reptilian cerebellum, and confirms the phylogenetic distribution of renal calbindin-D28K to the oldest major reptilian group.

Animals↗
PubMed1989

Ultrastructural localization of immunoreactive calbindin-D28k in the rat and monkey basal ganglia, including subcellular distribution with colloidal gold labeling.

Normal cellular function depends on the controlled flux of Ca++ within intracellular compartments and across the plasma membrane. Proteins that bind Ca++ are thought to contribute to the regulation of intracellular Ca++ and, perhaps more importantly, signal functional changes in cell activity. In the brain, calbindin-D28k is among a class of calcium-binding proteins that are widely and heterogeneously distributed in select populations of neurons, among them neostriatal cells, but whose function is largely unknown. In this study of the monkey and rat neostriatum and globus pallidus, calbindin-D28k was localized with immunoperoxidase and immunogold methods in order to identify striatal cell populations that contain this protein and the subcellular compartments in which it is likely to function. Light and electron microscopy showed intense and extensive labeling of immunoreactive calbindin-D28k in the cell bodies, dendrites, and spines of medium-sized neostriatal spiny neurons and in their axon terminals which end in the globus pallidus. More discrete labeling with a gold-conjugated second antibody showed that the predominant site of calbindin-D28k was the matrix of the cytoplasm. Gold label was also associated with the karyoplasm of spiny cells and with the neurofilaments and axoplasmic matrix of striatopallidal axons and terminals, respectively. Membranes were either sparsely labeled (endoplasmic reticulum, mitochondria) or devoid of gold particles (nuclear envelope and plasmalemma). Radioimmunoassays of striatal subcellular fractions supported the anatomical findings by indicating that the soluble fractions of neostriatal tissue homogenates contained most of the calbindin-D28k immunoreactivity and that washes from forebrain synaptosomes treated with Triton X-100 yielded high levels of immunoreactive calbindin-D28k. These findings show that immunoreactive calbindin-D28k is localized to spiny neurons of the striatopallidal pathway and are consistent with previous observations on subcellular localization in nonneuronal tissues. If, as recently speculated, calbindin-D28k regulates calcium concentrations in neostriatal spiny neurons, this feature may be particularly involved with the high density of glutamatergic inputs to these cells. More work is needed to determine whether calbindin-D28k, when complexed to Ca++ in neostriatal spiny cells, signals the activation of protein kinases, phosphorylation, and/or neurotransmitter release, as has been shown for other Ca++-binding proteins in mammalian tissues.

Animals↗
PubMed1991

Subpopulations of GABAergic neurons containing parvalbumin, calbindin D28k, and cholecystokinin in the rat hippocampus.

The possible coexistence of calbindin D28k with parvalbumin and of calbindin D28k with cholecystokinin was studied in nonpyramidal cells of the rat dorsal hippocampal formation. Neighbouring Vibratome sections were immunostained either for calbindin D28k and parvalbumin or for calbindin D28k and cholecystokinin. The cells, halved during sectioning, were identified in both sections immunostained for different antigens. The coexistence of calbindin D28k and parvalbumin in the same neuron was rare throughout the hippocampal formation with the exception of stratum oriens of the CA1 region, where 9.6% of the parvalbumin-immunoreactive cells also contained calbindin D28k. In stratum radiatum of the CA3 region, calbindin D28k and cholecystokinin coexisted in 12.5% and 21.2% of the calbindin D28k and cholecystokinin-immunoreactive cells, respectively. In other regions of the hippocampal formation, the two markers coexisted in less than 5% of the cells of either type. The present results demonstrate that calbindin D28k-, parvalbumin- and cholecystokinin-containing nonpyramidal cells represent largely nonoverlapping cell populations and may thus be involved in different inhibitory circuits.

Animals↗
PubMed1994

Calbindin-D28k immunoreactivity within the cholinergic and GABAergic projection neurons of the basal forebrain.

The purpose of this study was to determine whether the calcium binding protein calbindin-D28k was present within the cortically projecting basal forebrain neurons of various rodent species not previously examined. Double-label immunocytochemistry was performed using antibodies against calbindin-D28k and choline acetyltransferase (ChAT) to detect the presence of the calcium binding protein within the cholinergic basal forebrain neurons of various species (i.e., humans, rats, mice, gerbils, guinea pigs). Antibodies against calbindin-D28k, ChAT, and glutamic acid decarboxylase (GAD) were also used in combination with a cortically injected retrograde tracer (Fluoro-Gold) to determine whether calbindin-D28k immunoreactive (IR) neurons within the basal forebrain projected to the frontoparietal cortex. The nucleus basalis of rats was examined for the presence of calbindin-D27k IR within the GABAergic basal forebrain neurons. All species examined had cholinergic, GABAergic, and calbindinergic neurons within the basal forebrain; however, only the cholinergic neurons within the human nucleus basalis of Meynert were also immunoreactive for calbindin-D28k. Although all rodent species had both cholinergic and GABAergic basal forebrain neurons that contained the Fluoro-Gold dye, none of the calbindin-D28k IR neurons, detected using monoclonal and polyclonal antibodies, were found to contain the retrograde tracer. These results indicate that the cortically projecting cholinergic and GABAergic basal forebrain neurons within these rodent species do not contain calbindin-D28k. Therefore, age- and disease-related loss of nucleus basalis projection neurons may not be mediated by alterations in calbindin-D28k.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Postnatal development of parvalbumin and calbindin D28K immunoreactivities in the cerebral cortex of the rat.

Parvalbumin and calbindin D28k immunoreactivities were examined in the neocortex of the rat during postnatal development. Parvalbumin-immunoreactive nonpyramidal neurons first appear in layer V and later in layers VI and IV, and then in II and III. Immunoreactive terminals forming baskets surrounding unlabelled somata appear about 2 days later. The first parvalbumin-immunoreactive neurons appear in the retrosplenial and cingulate cortices, and the rostral region of the primary somatosensory cortex at postnatal days 8 or 9 (P8-P9). These regions are followed by the primary visual, primary auditory and motor cortices at P11. Parvalbumin immunoreactivity appears last in the secondary areas of the sensory regions and association cortices. Adult patterns are reached at the end of the 3rd week. Calbindin D28K-immunoreactive nonpyramidal neurons are found at birth in all cortical layers excepting the molecular layer. The intensity of the immunoreaction increases during the first 8 or 11 days of postnatal life, first in the inner and later in the upper cortical layers, following, therefore, an "inside-out" gradient. Heavily-labelled calbindin D28K-immunoreactive nonpyramidal cells dramatically decrease in number from P11 to P15 due mainly to a decrease of the multipolar subtypes. This suggests that two populations of calbindin D28k-immunoreactive nonpyramidal neurons are produced in the neocortex during postnatal development: one population of neurons transitorily expresses calbindin D28k immunoreactivity; the other population is composed of neurons that are permanently calbindin D28k immunoreactive. In addition to heavily labelled nonpyramidal cells, a band of weakly labelled pyramid-like neurons progressively appears in layers II and III throughout the cerebral cortex, beginning in layer IV in the somatosensory cortex by the end of the 2st week. Adult patterns are reached at the end of the 3rd week. These results indicate that parvalbumin and calbindin D28k immunoreactivities in the cerebral neocortex follow different characteristic patterns during postnatal development. The appearance of parvalbumin immunoreactivity correlates with the appearance of the related functional activity in the different cortical regions, and, probably, with the appearance of inhibitory activity in the neocortex. On the other hand, the early appearance of calbindin D28k immunoreactivity in the neocortex may be related to the early appearance of calbindin immunoreactivity in many other brain regions, and suggests another, as yet unknown, role for this calcium-binding protein during development of the cerebral cortex.

Animals↗
PubMed1992

Effects of methylprednisolone and uremia on renal and intestinal calbindin-D in the rat.

The effects of glucocorticoids on renal and intestinal calcium binding protein (calbindin-D28K and calbindin-D9K) were examined in normal and uremic rats. Chronic uremic rats and normal controls were treated with either methylprednisolone (MP) 1.3 mg/kg/d or isotonic saline given as a continuous intraperitoneal infusion for 1 week before sacrifice. Renal calbindin-D28K was measured by rocket immunoelectrophoresis and intestinal calbindin-D9K was measured by an enzyme-linked immunoadsorbent assay. Methylprednisolone treatment of chronic uremic rats increased plasma phosphate levels (P < 0.05), but plasma calcium and 1,25-dihydroxyvitamin D3 were unchanged in all groups. MP treatment did not affect the renal calbindin-D28K in either normal or uremic rats. In normal rats, MP treatment reduced intestinal calbindin-D9K by 28% when compared to placebo (P < 0.05). In contrast, chronic uremia increased renal calbindin-D28K by 51% and 38% (P < 0.001) in placebo and MP treated uremic rats, respectively, while intestinal calbindin-D9K was unchanged. Thus, MP treatment and chronic uremia induced different changes in renal and intestinal calbindin-D of the rat suggesting that different mechanisms are involved in the regulation of these vitamin D dependent proteins.

Animals↗
PubMedDate not supplied

Opposing effects of ethanol and nicotine on hippocampal calbindin-D28k expression.

Long-term ethanol exposure produces multiple neuroadaptations that likely contribute to dysregulation of Ca(2+) balance and neurotoxicity during ethanol withdrawal. Conversely, nicotine exposure may reduce the neurotoxic consequences of Ca(2+) dysregulation, putatively through up-regulation of the Ca(2+)-buffering protein calbindin-D(28k). The current studies were designed to examine the extent to which 10-day ethanol exposure and withdrawal altered calbindin-D(28k) expression in rat hippocampus. Further, in these studies, we examined the ability of nicotine, through action at alpha(7)(*)-bearing nicotinic acetylcholine receptors (nAChRs), to antagonize the effects of ethanol exposure on calbindin-D(28k) expression. Organotypic cultures of rat hippocampus were exposed to ethanol (50-100 mM) for 10 days. Additional cultures were exposed to 500 nM (-)-nicotine with or without the addition of 50 mM ethanol, 100 nM methyllycaconitine (an alpha(7)*-bearing nAChR antagonist), or both. Prolonged exposure to ethanol (>/=50 mM) produced significant reductions of calbindin-D(28k) immunolabeling in all regions of the hippocampal formation, even at nontoxic concentrations of ethanol. Calbindin-D(28k) expression levels returned to near-control levels after 72 h of withdrawal from 10-day ethanol exposure. Extended (-)-nicotine exposure produced significant elevations in calbindin-D(28k) expression levels that were prevented by methyllycaconitine co-exposure. Co-exposure of cultures to (-)-nicotine with ethanol resulted in an attenuation of ethanol-induced reductions in calbindin-D(28k) expression levels. These findings support the suggestion that long-term ethanol exposure reduces the neuronal capacity to buffer accumulated Ca(2+) in a reversible manner, an effect that likely contributes to withdrawal-induced neurotoxicity. Further, long-term exposure to (-)-nicotine enhances calbindin-D(28k) expression in an alpha(7)* nAChR-dependent manner and antagonizes the effects of ethanol on calbindin-D(28k) expression.

Animals↗
PubMedDate not supplied

Nonphosphorylated neurofilament protein and calbindin immunoreactivity in layer III pyramidal neurons of human neocortex.

Subpopulations of pyramidal neurons in the neocortex have been shown to contain nonphosphorylated neurofilament protein (NPNFP) and calbindin D28K (Morrison et al., 1987; Campbell and Morrison, 1989; Hof et al., 1990; Kobayashi et al., 1990; Hof and Morrison, 1991; Mesulam and Geula, 1991). However, it is not known what relations, if any, exist between the pyramidal neurons containing each of these proteins. In this study, the expression of NPNFP and calbindin immunoreactivity was compared in six regions of human neocortex. Characteristic laminar patterns of immunoreactivity for each protein were seen in most regions examined, and both NPNFP- and calbindin-labeled pyramidal neurons were found in layer III. However, the pyramidal neurons labeled with NPNFP and calbindin differed in several respects. First, the sublaminar distribution of NPNFP-labeled pyramids within layer III differed across regions, ranging from an even distribution throughout the layer in a visual association region (area 18) to a predominance of labeled neurons in the deep half of that layer in a higher association region (area 20). The distribution of calbindin-immunoreactive pyramidal neurons also varied regionally, but in a different manner than that of the NPNFP-labeled neurons. Second, in every region examined, the average size of NPNFP-labeled layer III pyramids was greater than that of calbindin-immunoreactive pyramids. However, there was substantial regional heterogeneity in the extent to which the size distributions of neurons in each of the two populations overlapped. Third, in the regions in which NPNFP- and calbindin-immunoreactive neurons were most similar in size, the amount of colocalization (as identified by double-labeling studies) was also greatest. Similarly, in the regions in which there was minimal overlap in the size of the NPNFP- and the calbindin-immunoreactive neurons, there was minimal colocalization. These regional characteristics of NPNFP- and calbindin-immunoreactive layer III pyramidal neurons have implications for the involvement of these neuronal populations in Alzheimer's disease.

Adult↗
PubMed1992

Age-related alterations in calbindin-D28K induction by 1,25-dihydroxyvitamin D3 in primary cultures of rat renal tubule cells.

In vivo studies have indicated that renal calbindin-D28K protein and mRNA levels decrease in adult and old rats, and this decrease parallels the age-associated decline in serum 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] levels. However, diminished renal responsiveness to 1,25-(OH)2D3 with advancing age could also contribute to decreased calbindin-D28K expression. To study renal responsiveness with age, primary cell cultures were established from the kidney cortices of young (1 month old), adult (10-12 months old), and old (20-24 months old) rats. Cells were incubated in medium K-1 containing 2% fetal calf serum. Calbindin-D28K protein levels were determined by Western blot and enzyme-linked immunosorbent assay. In young animals, the levels of calbindin-D28K declined from 12.1 +/- 1.3 micrograms/mg protein in the intact kidney to 1.6 +/- 0.07 micrograms/mg protein in cells that had been cultured for 3 days in the absence of 1,25-(OH)2D3. This sharp decline in calbindin-D28K protein concentration moderated by days 6-8. The continuous presence of 10(-7) M 1,25-(OH)2D3 in the medium did not abolish the decline. The low levels of calbindin-D28K in the cells cultured in the absence of 1,25-(OH)2D3 provided an excellent experimental system in which to compare the response of the cells to 1,25-(OH)2D3 between age groups. In cultured cells treated with 1,25-(OH)2D3 for 72 h, calbindin-D28K induction was greater in cells from adult and old animals compared to cells from young animals. The ratios of calbindin-D28K content (with vitamin D/without vitamin D) were 2.2 +/- 0.2, 4.7 +/- 0.5, and 7.1 +/- 1.5 for young, adult, and old cells, respectively. These studies suggested that the observed in vivo decrease in renal calbindin-D28K with age is primarily due to the lowered circulating 1,25-(OH)2D3.

Aging↗
PubMed2000

Effect of chronic metabolic acidosis on calbindin expression along the rat distal tubule.

Calbindin D28k has been reported to be involved in the transcellular calcium transport along the rat distal tubule. It has also been shown that chronic metabolic acidosis (CMA) induces significant hypercalciuria. The present study investigated whether CMA affects the mRNA and the protein expression of calbindin D28k along isolated distal tubule (DT) of rats. The animals were made acidotic by adding 0.28 mol/L NH4Cl to the drinking water for 7 d. This maneuver was associated with an increase in plasma ionized calcium. Inulin clearance experiments demonstrated that metabolic acidosis did not affect GFR, but it significantly increased both total and fractional urinary calcium excretion. To define the role of calbindin D28k, total RNA was extracted from DT, identified, and microdissected from collagenase-treated kidneys. cDNA was synthesized from RNA using reverse transcriptase and oligo(dT)(12-18) primers. Calbindin D28k mRNA abundance was semiquantified by a competitive reverse transcription-PCR, using an internal standard of cDNA that differed from the wild-type calbindin D28k by a deletion of 86 bp. The reverse transcription-PCR was performed starting from the same amount of total RNA. For each set of experiments, control and acidotic rats were studied in parallel. The identity of the DT was further verified by the presence of the thiazide-sensitive NaCl cotransporter (rTSC1) mRNA. Calbindin D28k mRNA abundance was 0.89 +/- 0.21 amol/ng total RNA in DT of CMA rats (n = 5) compared with 0.30 +/- 0.12 amol/ng total RNA of control rats (n = 5) (P < 0.05). Using specific rabbit polyclonal anti-calbindin D28k antibody, Western blotting was performed starting from thin slices of outer cortex. Densitometric analysis revealed that in acidotic rats (n = 7) there was a 17 +/- 5% (P < 0.05) increase in calbindin D28k protein abundance compared with controls (n = 7). These results indicate that in the rat, ammonium chloride loading induces an increase in filtered ionized calcium load that is associated with a significant upregulation of calbindin D28k both at the mRNA and protein level. These last effects will help to reduce the concomitant hypercalciuria, thus mitigating the consequence of CMA on calcium metabolism.

Acidosis↗
PubMed1989

Effect of hormones and development on the expression of the rat 1,25-dihydroxyvitamin D3 receptor gene. Comparison with calbindin gene expression.

We have used specific cDNAs to the rat vitamin D receptor (VDR) and to the mammalian vitamin D-dependent calcium-binding proteins (calbindin-D9k in intestine and calbindin-D28k in kidney) in order to obtain a better understanding of the regulation of the VDR gene and its relationship to calbindin gene expression. Hormonal regulation and development expression of the rat VDR gene were characterized by both Northern and slot blot analyses. Administration of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3; 25 ng/day for 7 days) to vitamin D-deficient rats resulted in an increase in calbindin mRNA in intestine and kidney but no change in VDR mRNA in these tissues. Vitamin D-deficient rats responded to dexamethasone treatment (100 micrograms/100 g of body weight/day for 4 days) with a 2.5-fold increase in intestinal VDR mRNA which was accompanied by a 4-fold decrease in intestinal calbindin-D9k mRNA. Developmental studies indicated a pronounced increase in renal VDR mRNA and calbindin-D28k mRNA between birth and 1 week of age. In the intestine, an induction of VDR and calbindin-D9k gene expression was observed at a later time, during the 3rd postnatal week (the period of increased duodenal active transport of calcium). Taken collectively, our data indicate that in the adult rat, target tissue response to hormone is not modified by a corresponding alteration in new receptor synthesis. However, developmental studies indicate that the induction of 1,25(OH)2D3 receptor mRNA is correlated with the induction of calbindin gene expression. Our results also demonstrate that glucocorticoid administration can result in an alteration in intestinal calbindin and VDR gene expression.

Aging↗
PubMed1995

Calbindin-D28k in subsets of medulloblastomas and in the human medulloblastoma cell line D283 Med.

OBJECTIVE: To evaluate the antigenic expression of calbindin-D28k in surgically resected cerebellar medulloblastomas and the human medulloblastoma cell line D283 Med in relation to glial neoplasms, the human glioblastoma (U-251 MG) and rat glioma (C-6) cell lines, and other primary and metastatic brain tumors. DESIGN: Immunohistochemical staining was performed using an antiserum and a monoclonal antibody against calbindin-D28k on (1) formalin-fixed, paraffin-embedded human, predominantly posterior fossa, brain tumor specimens (49 medulloblastomas, 59 glial and mesenchymal primary central nervous system tumors, 1 posterior fossa rhabdoid tumor, and 34 metastatic tumors); (2) formalin-70% alcohol-, or Bouin's-fixed tumor cell lines (D283 Med, U-251 MG, and C-6) maintained in a three-dimensional gelatin foam (Gelfoam matrix) system, with or without treatment with dibutyryl cyclic adenosine monophosphate; and (3) formalin-fixed, paraffin-embedded C-6 glioma cells transplanted intracerebrally to rats. RESULTS: Calbindin-D28k immunohistochemical staining was detected in 20 of 49 cerebellar medulloblastomas and in cells of the human medulloblastoma cell line D283 Med grown in gelatin Gelfoam matrices, with or without treatment with dibutyryl cyclic adenosine monophosphate. In surgical resection specimens, calbindin-D28k reactivity was evident in populations of poorly differentiated cells of classic (non-nodular) medulloblastomas (16/20) and in mature Purkinje neuronlike phenotypes in medulloblastomas with ganglion cells (4/6) but was absent in desmoplastic medulloblastomas, including in areas of neoplastic neuritogenesis ("pale islands") (0/23). Calbindin-D28k staining was also present in D283 Med explants for up to 29 days in vitro. Reactivity was more widespread in dibutyryl cyclic adenosine monophosphate-treated cultures, coinciding with neuronal morphologic alterations of cultured cells. Focal calbindin-D28k stainig was present in neural-like cells of an embryonal cerebellar tumor with divergent mesenchymal, epithelial, and neuroectodermal/neuroendocrine differentiation suggestive of a malignant rhabdoid tumor. No calbindin-D28k staining was obtained in primary glial and mesenchymal (intra- and extra-axial) brain tumors (0/59), in explants of human glioblastoma cell line U-251 MG, or in the rat glioma line C-6 maintained in Gelfoam matrices or transplanted intracerebrally. Among 34 epithelial and mesenchymal tumors metastatic to the posterior fossa, only subpopulations of cells in two small-cell (neuroendocrine) carcinomas originating in the lung were calbindin positive. CONCLUSION: Calbindin-D28k expression in classic medulloblastomas, medulloblastomas with ganglion cells, and in the human medulloblastoma cell line D283 Med (which was derived from a metastatic classic medulloblastoma) suggests a phenotypic kinship between subsets of this tumor and neuronal progeny of the ventricular neuroepithelium, thus conferring additional support for its neuroblastic nature.

Animals↗
PubMed1990

Regulation of calbindin-D28K gene expression in the chick intestine: effects of serum calcium status and 1,25-dihydroxyvitamin D3.

Calbindin-D28K is a member of a superfamily of calcium binding proteins that share a common avidity for the divalent calcium ion. The ambient concentration of calcium in the blood circulation is thought to orchestrate the release of parathyroid hormone and calcitonin and to govern the activity of renal 1-hydroxylase and thereby synthesis of 1,25-dihydroxyvitamin D3. We report here the results of experiments designed to assess the possible contribution of dietary calcium status upon calbindin-D28K gene expression in the intestine of vitamin D-deficient chicks. The actions of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and dietary calcium intake upon intestinal calbindin-D28K and calbindin-D28K mRNA were monitored by ELISA and dot-blot hybridization analyses, respectively. Vitamin D3-deficient chicks were fed either a calcium-supplemented diet (3% w/w) or a diet containing low calcium (0.4% w/w). These dietary manipulations evoked a highly significant change in serum calcium status. However, the levels of calbindin-D28K protein and its corresponding mRNA were unaffected. Administration of 1,25-(OH)2D3 (1-16 nmol per animal) to both "normocalcemic" and hypocalcemic vitamin D-deficient chicks resulted in an equivalent stimulation of duodenal calbindin-D28K accumulation of calbindin-D28K mRNA. Intestinal calbindin-D28K was stimulated 20- to 28-fold (above control levels) by 6-8 nmol 1,25-(OH)2D3 in both dietary treatment groups when measured 48 h after the single injection. Hence, despite the existence of a relatively large difference in serum calcium levels, the molecular actions of 1,25-(OH)2D3 in the vitamin D-deficient animal are apparently well insulated from serum calcium chemistry. These observations support the notion that, in the absence of vitamin D3, the calcium ion per se is unable to modulate the calbindin-D28K gene in vivo.

Animals↗
PubMed1995

Brain injury and tumor necrosis factors induce calbindin D-28k in astrocytes: evidence for a cytoprotective response.

Calbindin is a 28 kDa calcium-binding protein expressed in restricted neuronal populations in the mammalian brain where it may play a role in protecting neurons against excitotoxic insults. Recent findings indicate that electrical activity and some neurotrophic factors can induce the expression of calbindin in neurons. We now report that brain injury, effected by systemic administration of the excitotoxin kainate or mechanical trauma, induces expression of calbindin in cells of the corpus callosum and subcortical white matter. Immunohistochemical analysis using antibodies to the astrocyte-specific proteins (glial fibrillary acidic protein and S-100 beta) established the identity of calbindin immunoreactive cells as astrocytes. Because brain injury is known to induce the expression of several neurotrophic factors and cytokines, we employed cultures of hippocampal and neocortical astrocytes to test the hypothesis that such factors can induce expression of calbindin in astrocytes. Tumor necrosis factors (TNF alpha and TNF beta), cytokines that are expressed in response to brain injury, induced the expression of calbindin in cultured rat hippocampal and neocortical astrocytes. Two neurotrophic factors, basic fibroblast growth factor and nerve growth factor, did not induce calbindin in astrocytes. TNF-treated, calbindin-expressing astrocytes were resistant to acidosis and calcium ionophore toxicity, suggesting that TNFs and calbindin may serve a cytoprotective role in astrocytes in the injured brain.

Animals↗
PubMed1987

Ontogeny of the calcium binding protein calbindin D-28k in the rat nervous system.

Calbindin D-28k immunoreactivity appeared at embryonal day 14 (E14) in the central nervous system as well as in the sensory organs and at E15 in the peripheral nervous system of the rat. At E14 the infundibular process of the diencephalon, cells of the posterior hypothalamus and of the dorsal thalamus were the only structures strongly immunostained in the brain, whereas neurons of the basal plate of the spinal cord, medulla oblongata and of the outermost layer of the cerebral cortex were only faintly labeled. Calbindin positive cerebellar Purkinje cells could be discerned at E15 together with a few cells in the hippocampus and in ganglia of the cranial nerves. At E19 various mesencephalic and metencephalic structures, spinal ganglion cells and basal ganglia displayed calbindin immunoreactive cells. The adult pattern of calbindin immunoreactivity (Garcia Segura et al. 1984) was reached before birth in most brain regions. In general, cells which displayed calbindin during brain development were also calbindin positive in the adult animal. Exceptions to this rule were cells of deep nuclei of the cerebellum and non-neuronal cells which transiently expressed calbindin during development. Calbindin appeared in a given brain region almost invariably 1 or 2 days after the cessation of cell division and the beginning of neuronal migration and extension of neuronal processes. The calcium binding protein calbindin might influence these Ca2+-dependent processes.

Animals↗
PubMed1992

Calbindin D-28k-immunoreactivity in rat muscle spindles during postnatal maturation and after denervation.

Calbindin D-28k-immunoreactivity has been demonstrated in some of the intrafusal muscle fibres and in the capsule of adult rat muscle spindles. In this study, the immunocytochemical localization of calbindin D-28k in the muscle spindles of triceps surae muscle was studied during postnatal maturation and after denervation. In young rats calbindin D-28k-immunoreactivity was seen in a few intrafusal fibres, first at the age of 4 days. At the 7th day, three calbindin D-28k-immunoreactive fibres and one unlabelled fibre were seen in most muscle spindles, as in adult rats. The spindle capsule and perineurial sheath of nerves were first seen to exhibit calbindin D-28k immunoreactivity at the age of 14 days, and thereafter the localization of calbinding D-28k-like immunoreactivity was similar to that in adult rats. After denervation, calbindin D-28k-immunoreactivity remained in intrafusal muscle fibres and the spindle capsule for a long period. After two months of denervation, calbindin D-28k immunoreactivity could still be seen in the spindle capsule, but the intrafusal fibres were not labelled. The innervation is known to have trophic effects on the intrafusal fibres. The present findings suggest that the expression of calbindin D-28k-immunoreactivity in maturating muscle spindles may be induced by the developing innervation. The decrease of calbindin D-28k-immunoreactivity in intrafusal fibres after denervation may be due to the loss of trophic factors released by the nerves.

Animals↗