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PubMed2000

Plasticity of the auditory brainstem: cochleotomy-induced changes of calbindin-D28k expression in the rat.

Calbindin is a calcium binding protein that is characteristically expressed in several auditory brainstem nuclei during ontogeny and is thought to serve as a buffer, protecting cells against toxic levels of calcium. Upon maturation, calbindin is drastically reduced or entirely lost in many auditory nuclei. We made cochleotomies in mature rats to study effects of deafening and deafferentation on the expression of calbindin in the auditory brainstem. Following unilateral cochleotomy, we observed a substantial increase in the number of calbindin-immunoreactive fibers and boutons in the ventral subdivisions of the ipsilateral cochlear nucleus. At the same time, calbindin-positive astrocytes emerged in the dorsal and ventral cochlear nucleus. Beyond the immediately affected ipsilateral cochlear nucleus, we found calbindin-positive neurons in the lateral superior olive and in the central inferior colliculus, both contralateral to the operation. The loss of one cochlea reduces auditory input and puts the flow of neuronal activity originating in the two ears out of balance. Our findings indicate that the need for the neuronal networks in the auditory brainstem to adjust to this drastically changed pattern of sensory signals invokes the expression of calbindin in glial cells as well as in directly and indirectly affected neuronal cell populations.

Animals↗
PubMed1997

Protein gene product 9.5-like and calbindin-like immunoreactivity in the nasal respiratory mucosa of perinatal humans.

BACKGROUND: Protein gene product 9.5 (PGP) and calbindin-D28k (calbindin) are neuroendocrine markers that have been localized to neuroendocrine cells in the developing tracheobronchial epithelium. Neuroendocrine cells may play some role in the development of the tracheobronchial epithelium. Little is known about the development of the nasal respiratory epithelium (RE). METHODS: Nasal respiratory mucosa from fetal and newborn humans was examined to determine immunoreactivity for PGP and calbindin. RESULTS: At all stages studied, cells of different morphologies displayed PGP-like immunoreactivity (-LI) and calbindin-LI. Columnar immunoreactive cells for both markers predominated, but labeled cells of different shapes were also observed. Most labeled columnar cells were in the RE at its border with olfactory epithelium (OE); a few similarly labeled columnar cells also appeared in this OE. In the lamina propria, PGP-LI was also seen in numerous thin branching fibers. Some of these branches penetrated into the epithelium, where fiber varicosities appeared to contact cells, some of which also exhibited PGP-LI. CONCLUSION: This study demonstrates that during development the human nasal RE contains different cell types, as illustrated by the assortment of epithelial cells displaying PGP-LI and calbindin-LI among unlabeled cells. Because PGP and calbindin immunoreactivities were found within neuroendocrine cells in previous studies, the present results indicate that the developing human nasal RE also may support a number of neuroendocrine cells. Furthermore, at least some of these cells may form synaptic contacts with nerve fibers from outside the epithelium.

Calbindin 1↗
PubMed2000

Calbindin D28k-like immunoreactivity during the formation of the enamel-free area in the rat molar teeth.

Previous studies have demonstrated the presence of calbindin D28k in the ameloblasts derived from the inner enamel epithelium. The occlusal surfaces of the rodent molars partly lack the enamel covering, which is referred to as enamel-free area (EFA). In the present study, we compared the immunohistochemical localization of calbindin D28k-like immunoreactivity (CB-LI) in the cells at the EFA (EFA cells) and ameloblasts of the rat molar teeth at the light microscopic level. CB-LI was strong in the ameloblasts of the presecretory through the protective stages, while it was faint at the late secretory to transitional stages. However, some mature ameloblasts lacked the immunoreactivity. On the other hand, the majority of EFA cells showed distinct polarization and elongation that were absent in few cells at the early stage of EFA formation. At all stages, the EFA cells adjacent to the ameloblasts showed CB-LI, however, some cells adjacent to the mature ameloblasts lacked the reaction. Intensive CB-LI was demonstrated in EFA cells at the reduced enamel epithelium. These immunohistochemical findings suggest EFA cells have cytochemical properties similar to those of ameloblasts.

Ameloblasts↗
PubMed1996

Colonization of human lung grafts in SCID-hu mice by human colon carcinoma cells.

Human colon carcinoma cell lines were examined in a colonization assay using SCID-hu mice engrafted with human fetal lung (HFL) tissues. Cell lines SW620 and COLO 320DM, derived from metastatic tumors, colonized HFL grafts after i.v. injection into SCID-hu mice. Cell lines SW480 and T34 initiated from primary colon tumors were unable to colonize HFL grafts. The ability to colonize HFL grafts but not mouse lungs of SCID-hu-L mice correctly reflects the clinical origin of these human colon carcinoma cell lines. Expression of a number of cell adhesion molecules was examined on SW480, SW620 and in vivo selected highly aggressive variants of SW620. NCAM and integrin alpha 3 expressed on the surface of SW480 cells were lost from metastatic cells, while carbohydrate ligands sialyl Lewis x and a, previously shown to be upregulated in metastatic colorectal tumors, were expressed at higher levels on colonizing cells. Unlike SW480, SW620 and its in vivo selected variants expressed RNA for calcium binding protein calbindin-D28K, a neuroendocrine marker. Acquisition of neuroendocrine features might be of potential importance in the development of the metastatic phenotype.

Animals↗
PubMed1996

Presence of calbindin D28K and GAD67 mRNAs in both orthotopic and ectopic Purkinje cells of staggerer mice suggests that staggerer acts after the onset of cytodifferentiation.

We used in situ hybridization to study the expression of GAD67 and calbindin D28K mRNAs in developing mouse cerebellar Purkinje cells. Both genes are expressed prenatally; calbindin D28K mRNAs can be detected in Purkinje cells of embryonic day (E) 15 mice, whereas GAD67 mRNAs first appear slightly later, in E16 mice. The stunted Purkinje cells of staggerer (sg/sg) mutant mice maintain calbindin D28K and GAD67 expression. Our data suggest that the sg/sg mutation does not interfere with the transcriptional activation of these two genes, and might therefore act after the induction of specific gene expression in developing Purkinje cells.

Animals↗
PubMed1998

N-methyl-D-aspartate receptor-mediated, calcium-induced calcium release in rat dentate gyrus/CA4 in vivo.

Previously, by using in vivo microdialysis, we demonstrated a huge release of 45Ca2+ from prelabeled tissues to dialysate that was evoked by application of N-methyl-D-aspartate (NMDA) to the rat dentate gyrus (DG) and sector 4 of the cornu ammonis. To establish the mechanism of this phenomenon, in the present study, we characterized its NMDA receptor dependence, investigated the mechanism of 45Ca2+ removal from the cells, and evaluated the possible involvement of calcium-binding protein calbindin D28k and of ryanodine receptors. Microdialysis experiments demonstrated a dose-response relation between NMDA and 45Ca2+ release and sensitivity of this phenomenon to inhibition by 10 microM MK-801 and 5 mM 5-(N,N-dimethyl)-amiloride, thus indicating the NMDA receptor dependence and a role of Na+/Ca2+ exchanger in mediating 45Ca2+ release from cells. Immunocytochemical experiments confirmed that DG granule cells in the investigated inbred rat strain are strongly calbindin D28k-immunopositive, indicating probable involvement of this protein. However, microdialysis studies demonstrated that NMDA-evoked 45Ca2+ release was suppressed by 100 microM dantrolene and 250 microM ryanodine, whereas 50 microM ryanodine stimulated this effect. This points to a key role in the investigated phenomenon of calcium-induced calcium release (CICR) via ryanodine receptors. To our knowledge, this is the first in vivo demonstration of NMDA-evoked CICR. We postulate the usefulness of microdialysis in such studies.

Animals↗
PubMed1996

Pyramidal cell dendrites are the primary targets of calbindin D28k-immunoreactive interneurons in the hippocampus.

The axonal arborization and postsynaptic targets of calbindin D28k (CB)-immunoreactive nonprincipal neurons have been studied in the rat dorsal hippocampus. Two types of neurons were distinguished on the basis of soma location, the characteristics of the dendritic free, and the axon arborisation pattern. Type I cells were located in stratum radiatum of the CA1 and CA3 regions and occasionally in strata pyramidale and oriens. These cells had multipolar or bitufted dendritic trees primarily located in stratum radiatum. Their axons could be followed for a considerable distance, arborised within stratum radiatum, and were covered with regularly spaced small boutons. As demonstrated with postembedding immunogold staining, their axon terminals were gamma-aminobutyric acid (GABA) immunoreactive, and formed symmetrical synapses predominantly on proximal and distal dendrites of pyramidal cells (28% and 58%, respectively), and occasionally on spines (9%) or on GABA-positive dendrites (5%). Type II cells were found exclusively in stratum oriens of the CA1 and CA3 regions and possessed large, fusiform cell bodies and long, horizontally oriented dendrites. Their axon initial segments turned towards the alveus and disappeared in a myelin sheet, which was often possible to follow into the white matter. We conclude that type I CB-immunoreactive cells are likely to represent a major source of inhibitory synapses in the dendritic region of pyramidal cells, which are responsible for the control of dendritic electrogenesis. The distribution of local collaterals of type II cells-if they have any-remains unknown, but their main axon is likely to project to the medial septum.

Animals↗
PubMed1998

Neurocalcin-immunoreactive cells in the rat hippocampus are GABAergic interneurons.

Neurocalcin (NC) is a recently described calcium-binding protein isolated and characterized from bovine brain. NC belongs to the neural calcium-sensor proteins defined by the photoreceptor cell-specific protein recoverin that have been proposed to be involved in the regulation of calcium-dependent phosphorylation in signal transduction pathways. We analyzed the distribution and morphology of the NC-immunoreactive (IR) neurons in the rat dorsal hippocampus and the coexistence of NC with GABA and different neurochemical markers which label perisomatic inhibitory cells [parvalbumin (PV) and cholecystokinin (CCK)], mid-proximal dendritic inhibitory cells [calbindin D28k (CB)], distal dendritic inhibitory cells [somatostatin (SOM) and neuropeptide Y (NPY)], and interneurons specialized to innervate other interneurons [calretinin (CR) and vasoactive intestinal polypeptide (VIP)]. NC-IR cells were present in all layers of the dentate gyrus and hippocampal fields. In the dentate gyrus, NC-IR cells were concentrated in the granule cell layer, especially in the hilar border, whereas in the CA fields they were most frequently found in the stratum radiatum. NC-IR cells were morphologically heterogeneous and exhibited distinctive features of non-principal cells. In the dentate gyrus, pyramidal-like, multipolar and fusiform (horizontal and vertical) cells were found. In the CA3 region most NC-IR cells were multipolar, but vertical and horizontal fusiform cells also appeared. In the CA1 region, where NC-IR cells showed most frequently vertically arranged dendrites, multipolar, bitufted and fusiform (vertical and horizontal) cells could be distinguished. All the NC-IR cells were found to be GABA-IR in all hippocampal layers and regions, and they represented about 19% of the GABA-positive cells. NC/CB, NC/CR and NC/VIP double-labeled cells were found in all hippocampal regions, and represented 29%, 24% and 18% of the NC-IR cells, respectively. NC and CCK did not coexist in the dentate gyrus; however, 9% of the NC-IR cells in the CA fields also contained CCK. No coexistence of NC with PV, SOM or NPY was found in any hippocampal region. We conclude that NC is exclusively expressed by interneurons in the rat hippocampus. NC-IR cells are a morphologically and neurochemically heterogeneous subset of GABAergic non-principal cells, which, on the basis of the known termination pattern of the colocalizing markers, are also functionally heterogeneous and are mainly involved in feed-forward dendritic inhibition in the commissural-associational and Schaffer collateral termination zones (CB containing cells), in innervation of other interneurons (CR- and VIP-containing cells), and in perisomatic inhibition (CCK-containing cells). NC is never present in perisomatic inhibitory PV-containing cells, or in feed-back distal dendritic inhibitory SOM/NPY-containing cells.

Animals↗
PubMed1999

On-line sample clean-up and chromatography coupled with electrospray ionization mass spectrometry to characterize the primary sequence and disulfide bond content of recombinant calcium binding proteins.

We have used on-line sample clean-up, concentration, and chromatography with electrospray ionization mass spectrometry (ESI-MS), to characterize and determine the presence of disulfide bonds in recombinant full-length rat brain calbindin D28K and two deletion mutants of the protein, one lacking EF-hand 2 (calbindin delta 2) and the other lacking EF-hands 2 and 6 (calbindin delta 2,6). The molecular weights of the expressed proteins dissolved in biological buffers were determined with high accuracy using a low-flow, pressurized chamber infusion system, that allows on-line protein clean-up by removing buffers/salts incompatible with ESI-MS. The molecular weight determinations showed that the amino-terminal methionine residues had been cleaved during the expression and isolation of the recombinant proteins. Approximately 85-90% of the protein sequences were confirmed by on-line HPLC-ESI-MS analysis of peptides generated by a lysyl endoproteinase C digestion. Comparisons of ESI-MS spectra of native and reduced calbindin D28K and delta 2 show that the full length- and delta 2 mutant-protein contain one disulfide bond. Molecular mass determinations of calbindin delta 2,6 showed that this protein contains a highly active cysteine residue that covalently binds a mercaptoethanol group, or forms a homodimer via a disulfide bond. The results show surprising differences amongst the deletion mutants of calbindin D28K with respect to the formation of disulfide bonds. These differences are not readily detected by other techniques and show that ESI-MS is a powerful, rapid method by which to detect disulfide linkages for intact proteins.

Amino Acid Sequence↗
PubMed2001

Expression of calbindin D28K in the dopaminergic mesotelencephalic system in embryonic and fetal human brain.

A subset of tyrosine-hydroxylase (TH) neurons of the substantia nigra (A9) containing calbindin D28K (CaBP) appeared to be less vulnerable to cell death induced by Parkinson's disease than the subset containing dopamine (DA) alone. Because grafting procedures of fetal human neurons are increasingly used in the therapy of Parkinson's disease, it is important to study the development of DA neurons coexpressing CaBP. In humans, the genesis of TH immunoreactivity of A9, of the ventral tegmental area (A10), and of the retrorubral area (A8) occurred during a 2-week period from the 4. 5th gestational week (g.w.) in the ventricular zone of the floor plate and the contiguous basal plate of the mesencephalon and diencephalon, i.e., the prosomeres p1-p3. Double-immunolabeled TH-CaBP neurons were detected from 5.5 g.w. on, in the first wave of DA neuron's migration, and were observed in their final residence in the dorsal A9 by 10.5 g.w. Calretinin immunoreactivity was expressed in TH-immunoreactive (IR) neurons from 10.5 g.w. on. Ascending TH-CaBP-IR axons were observed toward the telencephalon from 6-7 g.w. , reaching the anlage of the nucleus accumbens and amygdaloid complex at 10.5 g.w., but were not detected in the ganglionic eminence at this latter stage. Dopaminergic patches were detected at 13 g.w. in the anlage of the putamen, but no TH-CaBP-IR fibers were observed in the matrix at this stage. In conclusion, even if CaBP immunoreactivity was detected in TH-IR cell bodies during the embryonic period, the TH-CaBP-IR axonal terminal was observed earlier in some limbic-related areas than in the matrix compartment of the basal ganglia in humans.

Axons↗
PubMed2000

Calbindin-immunoreactive neurons in the reticular formation of the rat brainstem: catecholamine content and spinal projections.

Calbindin-D28k (calbindin) is a calcium-binding protein that is distributed widely in the rat brain. The localisation of calbindin immunoreactivity in the medulla oblongata and its colocalisation with adrenaline-synthesising neurons [phenylethanolamine-N-methyltransferase-immunoreactive (PNMT-IR)] was examined (Granata and Chang [1994] Brain Res. 645:265-277). However, detailed information about the distribution of calbindin-IR neurons in the reticular formation of the medulla oblongata in particular is lacking. In this report, the authors address this issue with an emphasis on the quantitation of calbindin-IR neurons, catecholamine neurons [tyrosine hydroxylase (TH)-IR, or PNMT-IR], and spinally projecting neurons in the ventral brainstem. Rats received injections of the retrograde tracing agent cholera toxin B (CTB) into the thoracic spinal cord or into the superior cervical ganglion. Immunocytochemistry was used to reveal calbindin, TH, PNMT, and CTB immunoreactivity. Ten calbindin-IR cell groups were identified within the pontomedullary reticular formation. Seven previously undescribed but distinct clusters of calbindin-IR neurons were found. Within the ventral pons, a population of calbindin-IR neurons occurred dorsal but adjacent to the A5 cell group. These calbindin-IR neurons did not contain either TH or PNMT immunoreactivity, and few if any of these neurons projected to the spinal cord. A distinct group of calbindin-IR neurons was present in the ventral medulla. Seventy-five percent of these calbindin-IR neurons contained TH immunoreactivity, 45% contained PNMT immunoreactivity, and 21% were spinally projecting neurons. Spinally projecting, calbindin-IR neurons were a subpopulation of PNMT-IR cells. In the caudal ventral medulla, no TH-IR or PNMT-IR cells were calbindin-IR. In the intermediolateral cell column, close appositions of calbindin-IR terminals on identified sympathetic preganglionic neurons as well as calbindin-IR synapses indicated that these neurons may affect directly the sympathetic outflow. The results demonstrate for the first time the existence of a new subpopulation of spinally projecting, PNMT-IR neurons in the rostral ventrolateral medulla.

Animals↗
PubMed2000

Calbindin D28k-immunoreactive afferent nerve endings in the laryngeal mucosa.

The distribution of the calbindin D28k in the laryngeal sensory structures was studied by immunohistochemistry, immunoelectronmicroscopy, and double immunofluorescence with calretinin-immunoreactivity. Moreover, origin of the nerve endings were observed using retrograde tracer, fast blue. Immunoreactivity for calbindin D28k was found in the various types of nerve endings in the larynx, namely, laminar nerve endings, nerve endings associated with the taste buds, intraepithelial nerve endings, and endocrine cells. The laminar endings with calbindin D28k-immunoreactivity were observed in the subepithelial connective tissue. In some endings, terminals were expanded. The laminar endings were also observed in the perichondrium of the epiglottic cartilage. In the epiglottic and arytenoid epithelia, thick nerve fibers with calbindin D28k-immunoreactivity ascending to taste buds and intragemmal nerve fibers were also observed. Within the epithelial layer, intraepithelial free nerve endings with calbindin D28k-immunoreactivity were observed. Furthermore, diffuse endocrine cells were observed within the laryngeal epithelium. By immunoelectron microscopy, immunoreaction products in the endings mentioned above were localized in the cytoplasm of the axon terminals and nerve fibers which contained with numerous mitochondria. Out of the 100 laminar endings, 18 endings were immunopositive for both calbindin D28k and calretinin, 33 were positive for calbindin D28k but negative for calretinin, and 49 were positive for only calretinin in the double immunofluorescence microscopy. The nerve fibers associated with the taste buds and the free nerve endings, which immunostained for calbindin D28k, were not stained with antibody against calretinin. After injection of the fast blue in the laryngeal mucosa, fast blue-labeled cells were mainly observed in the nodose ganglia. Of the total number of labeled cell in the nodose and dorsal root ganglia at the level C1 to Th2, 65.1% occurred in nodose ganglia (572/879, n = 6). In the nodose ganglia, 79.7% of labeled cells (456/572) were immunoreacted for calbindin D28k. The distribution of calbindin D28k-immunoreactivity may be differnt from that of calretinin. It is suggested that calbindin D28k have regulatory role on intracellular calcium concentration in the laryngeal sensory corpuscles.

Amidines↗
PubMed2000

Maternal adrenalectomy at the early onset of gestation impairs the postnatal development of the rat hippocampal formation: effects on cell numbers and differentiation, connectivity and calbindin-D28k immunoreactivity.

The possible role of the maternal glucocorticoids on the postnatal development of the hippocampus was tested with bilateral adrenalectomy of pregnant rats. Surgery was performed 24 hr after sperm-positiveness was determined. The offspring from adrenalectomized mothers, compared with animals from control sham-operated mothers, showed decreased body weight and increased brain weight. The CA1 field of the hippocampus of these animals showed lower number of both Nissl-stained and Calbindin-immunoreactive cells, whereas the granule cell layer of the dentate gyrus showed higher number of both populations. Both types of cell numbers were statistically similar from postnatal Day 21, however, suggesting some compensatory mechanism. The neuronal populations of adrenalectomized animals appeared with a delay in the development of their dendritic trees, cytoplasmic differentiation, and synaptic connections. In the same way, both septohippocampal and hippocamposeptal projections appeared delayed in the adrenalectomized animals with respect to control ones by several days, mainly with regard to regressive events typical of the first 8 days of age. The ultrastructural study showed that every ADX postnatal group appeared more immature than the corresponding control group. These results suggest that gestational levels of maternal glucocorticoids (that were removed by adrenalectomy) influence the normal postnatal development of the hippocampus as reflected in neuron numbers and cell maturation, as well as in the developmental timing of the pattern of connectivity, and that this effect must be accomplished both in neuroepithelium and post-mitotic cells before the endogenous fetal hormones are secreted and reach concentrations capable to produce a response.

Adrenalectomy↗
PubMed1992

Calbindin-D28k in the basal ganglia of patients with parkinsonism.

An immunohistochemical study was carried out to investigate the topographic distribution of calbindin-D28k in the human basal ganglia and substantia nigra and its alterations in patients with idiopathic Parkinson's disease (PD), parkinsonism-dementia complex on Guam, progressive supranuclear palsy, and striatonigral degeneration. In normal control subjects, calbindin-D28k immunoreactivity was identified in the medium-sized neurons and neuropil of the matrix compartment of the striatum, the woolly fiber arrangements of the globus pallidus, and the fiber structures of the pars reticulata of the substantia nigra. Calbindin-D28k expression in the basal ganglia of patients with PD and parkinsonism-dementia on Guam was not different from that of control subjects, suggesting that the matrical output pathway is spared in these disorders. In contrast, its disruption is inferred from the observed disorganization of woolly fibers in the globus pallidus of patients with progressive supranuclear palsy and the reduced calbindin-D28k reactivity in the putaminal matrix and the pars reticulata of the substantia nigra of subjects with striatal degeneration. Thus, our results indicate that calbindin-D28k is a useful marker for the projection system from the matrix compartment and that its expression is modified in patients with progressive supranuclear palsy and striatal degeneration.

Aged↗
PubMed1994

The role of calcium-binding proteins in selective motoneuron vulnerability in amyotrophic lateral sclerosis.

The factors contributing to selective motoneuron loss in amyotrophic lateral sclerosis (ALS) remain undefined. To investigate whether calcium-binding proteins contribute to selective motoneuron vulnerability in ALS, we compared calbindin-D28K and parvalbumin immunoreactivity in motoneuron populations in human ALS, and in a ventral spinal cord hybrid cell line selectively vulnerable to the cytotoxic effects of ALS IgG. In human autopsy specimens, immunoreactive calbindin-D28k and parvalbumin were absent in motoneuron populations lost early in ALS (i.e., cortical and spinal motoneurons, lower cranial nerve motoneurons), while motoneurons damaged late or infrequently in the disease (i.e., Onuf's nucleus motoneurons, oculomotor, trochlear, and abducens nerve neurons) expressed markedly higher levels of immunoreactive calbindin-D28K and/or parvalbumin. Motoneuron-neuroblastoma VSC 4.1 hybrid cells lost immunoreactive calbindin-D28k and parvalbumin following dibutyryl-cyclic AMP-induced differentiation and were killed by IgG from ALS patients. Undifferentiated calbindin/parvalbumin-reactive VSC 4.1 cells were not killed, nor were other cell lines expressing high levels of calbindin-D28K and parvalbumin immunoreactivity (substantia nigra-neuroblastoma hybrid cells and N18TG2 neuroblastoma parent cells). These studies suggest that decreased calbindin-D28K and parvalbumin immunoreactivity may help explain the selective vulnerability of motoneurons in ALS.

Adult↗
PubMed1995

Preferential loss of preproenkephalin versus preprotachykinin neurons from the striatum of Huntington's disease patients.

Preferential loss of basal ganglia neurons and terminals occurs in Huntington's disease (HD). Terminals of preproenkephalin medium-size spiny neurons are more vulnerable than terminals of preprotachykinin neurons, but the peptidergic neurons of origin have not yet been shown to die preferentially. We sought to determine, in the striatum, whether preproenkephalin neurons were lost to a greater extent than preprotachykinin neurons and to determine whether there were decreases in specific messenger RNA (mRNA) levels of preproenkephalin, preprotachykinin, and calbindin D28k. We found a grade-related decrease in the number of preprotachykinin- and calbindin D28k-labeled neurons per measuring field in the caudate nucleus of patients with HD. Three measures of the neuronal level of preprotachykinin mRNA were all significantly reduced (6-65% of control values) in HD caudate nucleus. No decline in calbindin D28k mRNA levels per neuron were found in HD striata compared to control striata. We found a greater loss of preproenkephalin neurons per field than preprotachyknin neurons per field in the caudate nucleus of HD brains compared to control brains. Preprotachykinin neurons are lost in HD in a grade-related manner and surviving preprotachykinin neurons are impaired in function. However, preproenkephalin neurons are lost to a greater extent than preprotachykinin neurons, which may explain preferential changes found in projection regions of the striatum. Declines in neuropeptide mRNA may be specific in HD, since calbindin D28k mRNA levels were unchanged. Alterations in the levels of expression of preproenkephalin and preprotachykinin mRNA may be direct or indirect effects of the HD mutation.

Adult↗
PubMed1986

Calcium-binding protein (28,000 Mr calbindin-D28k) in kidneys of the bullfrog Rana catesbeiana during metamorphosis.

A protein of approximately 28,000 relative molecular mass (Mr) cross-reacting with antiserum against the 28,000-Mr rat renal calcium-binding protein (calbindin-D28k) has been localized in the kidney of a salientian amphibian, Rana catesbeiana. Cells reactive for calbindin-D28k were found in the distal tubule at all stages of metamorphosis by the unlabeled antibody peroxidase-antiperoxidase technique. Adult kidneys appeared to have more calbindin-D28k-positive cells. The renal corpuscle, neck, and proximal tubule were negative. An immunoreactive 28,000-Mr band that comigrated with the band of calbindin-D28k was visualized by the immunoblot technique. The finding of the 28,000-Mr calbindin-D in the anamniotic kidney demonstrates that this calcium-binding protein (CaBP) is phylogenetically older than our previous studies of higher vertebrates had revealed (Rhoten et al., 1985). Although the function of calbindin-D28k in the distal nephron is unknown, this CaBP can now be presumed to have functional significance in the mesonephric as well as the metanephric kidney.

Animals↗
PubMed1988

An immunohistochemical study of the ontogeny of the horizontal cell in the rat retina using an antiserum against spot 35 protein, a novel Purkinje cell-specific protein, as a marker.

A sequence of morphological changes during the differentiation of retinal horizontal cells was studied by means of immunohistochemistry for spot 35 protein, a novel Purkinje cell-specific protein, in the rat retina. Spot 35-immunoreactive horizontal cell anlagen were first identified at embryonic day 18 (E18) in the outer zone of the neuroblastic cell layer as fusiform cells with slender inner and outer processes. As the development proceeded, the immunoreactive cells increased in number and intensity of the immunostaining, and the outer processes of the immunoreactive cells were often bifurcated close to their origin or at their periphery. At postnatal days 3 and 5 (P3 and P5), a regional difference in morphology of the immunoreactive horizontal cell anlagen was recognized: The immunoreactive cells near the ora serrata still assumed a bipolar shape, and those in the central portion of the retina had multiple processes. At P7 and P10, the immunoreactive cells in the periphery of the retina extended most of their outer processes in the plane of the retina, forming a network together with processes of adjacent immunoreactive horizontal cells. Their internally extending processes during these postnatal stages tended to be present in small numbers and to be short. At P14 all the immunoreactive horizontal cells extended their processes horizontally to form a tight bundle all the way along the outer plexiform layer. These findings indicate that spot 35 protein is a specific marker for the horizontal cells of the rat retina in the developmental process from their bipolar stage at E18 until reaching their mature configuration at P14.

Animals↗