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PubMed1992

Soybean lectin binding neurons in the visual cortex of the rat contain parvalbumin and are covered by glial nets.

We carried out qualitative and quantitative studies on the distribution of soybean agglutinin-labelled cells in the visual cortex of the rat. Lectin-positive nerve cells mostly showed the morphological characteristics of small and large multipolar basket cells. Only a few cells appeared to be bipolar with a vertical or horizontal orientation. By light microscopy, soybean agglutinin binding sites were seen as discontinuous, punctate perineuronal staining (or pericellular nets) on the surface of about 9% of cortical neurons. Lectin-positive cells were predominantly localized in layers IV and V (16.9 and 12.4% of all neurons), where the intensity of staining was also the strongest. Combining lectin- and immunohistochemistry on cryo semithin sections, lectin-positive cells were shown to contain parvalbumin. Nerve cells in the visual cortex containing the related calcium binding-proteins, calbindin or calretinin were never soybean agglutinin-positive. Some glial cells and their processes were also soybean agglutinin-positive. The structure of the soybean agglutinin-positive pericellular nets was similar to that of glial nets visualized with the Golgi-method. Electron microscopy revealed that lectin binding sites were localized on the membranes and cytoplasm of glial processes ensheathing the axon terminals that impinged upon neurons and their proximal dendrites. Synaptic clefts and axon terminals were never reactive, thus explaining the discontinuous punctate labelling of the neuronal surface. Lectin binding sites were also found on the trans-face of the Golgi-complex of some lectin positive neurons suggesting that N-acetylgalactosamine-containing glycoconjugates, which are selectively detected by the lectin, are synthesized, at least partly, within the labelled neurons. We therefore consider possible the existence of specific interactions between parvalbumin positive basket cells and the glial network surrounding them, by which the neuron may determine the conditions of its own microenvironment.

Animals↗
PubMed1984

Vitamin-D-dependent calcium-binding-protein and parvalbumin occur in bones and teeth.

Vit-D-Dependent calcium binding protein and parvalbumin have both been detected in ameloblasts and calcified cartilage by immunohistochemical techniques. These two Ca2+ binding proteins may play a crucial role in the local accumulation of Ca2+ ions during the process of mineralization. The mechanisms underlying the deposition of inorganic substances in bone and teeth during physiologic calcification are still the object of intense debate [1, 2]. The hypotheses concerning the factors controlling the initiation of mineralization can be subdivided into three large categories: enzymatic (or non-enzymatic) local elevation of phosphate and calcium [3,4,5,6,7], enzymatic removal of inhibitors of calcification [8] and direct nucleation of CaPO4 crystals on collagen fibrils [9]. In support of the first line of thought we report here the simultaneous occurrence of two different very high affinity Ca2+ binding proteins [vitamin-D-dependent CaBP = VD CaBP and parvalbumin = PV] in bones and teeth. During the studied age period and with immunohistochemical methods, we detected the proteins only in calcified cartilage of bones and in ameloblasts of teeth. We propose that VDCaBP and PV help increase the Ca2+ concentration at the calcification front in some regions involved in mineral deposition.

Animals↗
PubMed2000

Parvalbumin immunoreactive Cajal-Retzius and non-Cajal-Retzius neurons in layer I of different cortical regions of human newborn.

Neurons of layer I play an important role in the development of the basic structural and functional organization of the mammalian cerebral cortex. Basic data, however, concerning the spatial and temporal distribution of the neuron populations in layer I are still limited, especially for human material. The present study investigates the distribution of Cajal-Retzius (CR) and non Cajal-Retzius (NCR) neurons in thirteen cortical areas in the newborn human in terms of their relative density and possible subtypes. Neuronal populations were identified by immunohistochemistry for parvalbumin. Three main results are reported. First, parvalbumin-immunoreactive (Parv-ir) CR cells were observed in all of the neocortical areas examined. These areas also had a Parv-ir horizontal fiber plexus in deep layer I, confirming to the horizontal plexus classically associated with CR neurons. Second, many Parv-ir CR cells showed clear signs of degeneration. Third, in addition to the large CR cells, smaller Parv-ir NCR neurons occurred in many of the neocortical areas examined. These were morphologically heterogeneous and may represent several subtypes. By sampling across several areas, we were able to establish that these NCR cells occurred at higher density in primary sensory areas 3, 1, 17, and 41. Because of this variability in density of Parv-ir NCR cells, the ratio of Parv-ir CR to Parv-ir NCR cells is selectively lower in primary sensory areas. Recent investigations in somatosensory cortex of early postnatal rat report complex spatiotemporal patterns of correlated spontaneous activity among neurons in layer I (Schwartz et al. 1998). An interesting possibility is that regional variability in this activity may play a major role in the organization of cortical circuitry in different areas.

Axons↗
PubMed1984

Synthesis of a new chelating gel: removal of Ca2+ ions from parvalbumin.

The synthesis of a chelating gel which contains the effective metal chelating agent ethylenediaminetetraacetic acid covalently linked to amino-agarose is described. This gel is shown to be a rapid and extremely effective material for the removal of tightly bound, but labile metal ions from proteins without introducing contaminants into the biological system. The synthesis involves the formation of an amide linkage between the dangling carboxylate arm of the [Co(EDTA)Cl]2-complex and amino-agarose using a standard carbodiimide coupling reaction. The chelating gel is shown to remove approximately 98.5% of the calcium from fully bound Ca2-parvalbumin and over 99% of the europium from Eu2-parvalbumin.

Calcium↗
PubMed1989

Parvalbumins for calibrating acidic isoelectric focusing gels.

Partially purified fish and amphibian parvalbumins are compared to several proteins commonly used in commercial standard mixtures for calibrating isoelectric focusing gels. Parvalbumins are proffered as useful standards for acidic ranges on the basis of conformity to a set of five criteria.

Animals↗
PubMed1977

Parvalbumins from frog skeletal muscle (Rana temporaria L.). Isolation and characterization. Structural modifications associated with calcium binding.

Two parvalbumins have been isolated from the skeletal muscle of Rana temporaria L. Amino acid composition, tryptic peptide maps, isoelectric points, calcium content and ultraviolet as well as circular dichroism spectra have been determined. Investigation on antigenic properties revealed no antigenic determinants common to both components. The two protein molecules appear to belong to far related gene lineages. They are also different from the parvalbumins found in Rana esculenta muscle. Modifications of physical parameters, associated with calcium binding and dissociation are described. While antigenicity remained essentially unchanged, conformational changes were revealed by alterations of circular dichroism spectra.

Amino Acids↗
PubMed1978

Parvalbumins from coelacanth muscle. II. Amino acid sequence of the two less acidic components.

The primary structure of the two less acidic parvalbumins (pI = 5.44 and pI = 4.95) from coelacanth muscle (Latimeria chalumnae) has been determined. They differ only by the presence or absence of a N-terminal blocking group. By the use of the automatic degradation, 69 amino acids could be placed unambiguously in the N-terminal part and 24 amino acids following the single arginine 75. Tryptic peptides were used to establish the sequence and the position of the remaining residues. The two parvalbumins examined belong to the alpha-lineage, and the rate of their molecular evolution is comparable to that found in other vertebrates.

Amino Acid Sequence↗
PubMed1978

Parvalbumins from coelacanth muscle. III. Amino acid sequence of the major component.

The primary structure of the major parvalbumin (pI = 4.52) from coelacanth muscle (Latimeria chalumnae) has been determined. Sequence analysis of the tryptic peptides, in some cases obtained with beta-trypsin, accounts for the total amino acid content of the protein. Chymotryptic peptides provide appropriate sequence overlaps, to complete the localization of the tryptic peptides. Examination of the amino acid sequence of this protein shows the typical structure of a beta-parvalbumin. Its position in the dendrogram of related calcium-binding proteins corresponds to that usually accepted for crossopterygians.

Amino Acid Sequence↗
PubMed1978

Binding of calcium by parvalbumin fragments.

Parvalbumin fragments from carp pI 4.47 parvalbumin corresponding to its residues 1--75 and 76--108 bind Ca2+ with affinities corresponding to Kd 0.9 . 10(-4) M and Kd 3 . 10(-3) M, respectively.

Animals↗
PubMed1990

Partial nucleotide sequence of the parvalbumin from chicken thymus designated "avian thymic hormone".

The incomplete amino acid sequence of the protein identified as avian thymic hormone was recently reported [Brewer et al. (1989), Biochem. Biophys. Res. Commun. 160, 11555-1161], and a very high degree of homology to the parvalbumins was apparent. Using mixed oligonucleotide primers based on the reported protein sequence, we have succeeded in amplifying and cloning a 188 bp fragment of the coding region for this protein, beginning with double-stranded cDNA prepared from chicken thymus mRNA. The translated nucleotide sequence of this fragment and the reported amino acid sequence display substantial disagreement. Most notably, the nucleotide sequence indicates that the CD site of avian thymic hormone is a typical parvalbumin CD site.

Amino Acid Sequence↗
PubMed1989

Entorhinal fibers form synaptic contacts on parvalbumin-immunoreactive neurons in the rat fascia dentata.

The entorhinal cortex gives rise to a dense projection to the outer two-thirds of the dentate molecular layer. The main target neurons are the granule cells. This study demonstrates that entorhinal fibers labeled by anterograde degeneration also terminate on parvalbumin-containing non-granule cells in the rat fascia dentata. Since the calcium-binding protein parvalbumin was recently found coexistent with gamma-aminobutyric acid in inhibitory hippocampal neurons, the described connection provides evidence for a role of entorhinal fibers in feed-forward inhibition of the granule cells.

Animals↗
PubMed1989

Kindling induced changes in parvalbumin immunoreactivity in rat hippocampus and its relation to long-term decrease in GABA-immunoreactivity.

The immunoreactivity of parvalbumin (PV), a Ca2+-binding protein present in a subpopulation of interneurons, was studied in the hippocampal CA1 region during kindling epileptogenesis, induced by tetanic stimulation of the Schaffer collateral/commissural fibers. PV-immunoreactivity was increased in comparison to controls after 13 afterdischarges and after the induction of generalized seizures. A quantification of the number of PV-immunoreactive somata showed an increase of 20% in both stages of kindling. This level had returned to baseline level 31 days after the last seizure. These results imply that changes in PV-immunoreactivity are related to seizure activity rather than to the long-term increase in seizure sensitivity in kindled animals. Co-localization study in controls showed that 32% of PV-immunoreactive somata were also immunopositive for GABA. A colocalization study in stratum oriens and pyramidale on the stimulated side of kindled animals 31 days after the last generalized seizure showed neither a reduction in the number of PV-immunoreactive somata nor in the number of GABA-immunopositive cell bodies that co-localized with PV. In contrast, the number of GABA-immunoreactive somata that did not co-localize with PV was reduced by 50%. It has been shown that a large influx of Ca2+ plays a crucial role in epileptogenesis. Here we demonstrate that the presence of the calcium-binding protein parvalbumin seems to exert a protective effect against the process that leads to a decrease in GABA content.

Animals↗
PubMed1991

Parvalbumin-immunoreactive neurons in the cerebral cortex of the lizard Podarcis hispanica.

An antibody against the calcium binding protein parvalbumin selectively labels a set of neurons in the cerebral cortex of lizards. Golgi-like immunostained bipolar, multipolar and pyramid-like neurons appear mainly located in the inner plexiform layers. Parvalbumin-immunoreactive (PARV-IR) puncta are concentrated in the cell layer of the dorsal and dorsomedial cortices showing a basket-like distribution. The morphology and distribution of PARV-IR neurons and puncta overlap GABA-immunostaining in the cerebral cortex of lizards. Thus, it is likely that PARV-IR neurons are a subset of the cortical GABAergic neurons of lizards.

Animals↗
PubMed1993

Immunohistochemical localization of calretinin-, calbindin-D28k- and parvalbumin-containing cells in the hypothalamic paraventricular and supraoptic nuclei of the rat.

The localization of three calcium-binding proteins, calretinin, calbindin-D28k and parvalbumin, in the hypothalamic paraventricular and supraoptic nuclei of the rat was immunohistochemically examined on adjacent sections and their distribution patterns were compared. Overlap between the distribution of calretinin-immunoreactive cells and that of calbindin-D28k-immunostained cells was found in the rostrodorsal part of the supraoptic nucleus, and the caudoventral part of this nucleus contained predominantly calbindin-D28k-stained cells. Cells of the medial and lateral magnocellular subdivisions of the paraventricular nucleus were almost devoid of the calcium-binding proteins examined. No parvalbumin-immunostained cells were observed in either nucleus. This study provides a further characterization of cell bodies in the hypothalamic paraventricular and supraoptic nuclei.

Animals↗
PubMed1994

Changes in GABA and parvalbumin immunoreactivities in the cerebral cortex of lizards after narine occlusion.

Olfactory deprivation produced by narine occlusion has been suggested to reduce the activity in the cerebral cortex of lizards. Here we analyzed the short-term changes in GABA and parvalbumin (PV) immunoreactivities in the cerebral cortex of lizards after narine occlusion. The number and distribution of GABA- and parvalbumin-immunoreactive (IR) cells have been studied by immunocytochemistry in the cerebral cortex of control and olfactory-deprived lizards. The distribution of GABA-IR cells as well as that of PV-IR cells was similar in control and deprived animals, and PV-IR cells were GABA-IR in all cases. However, significant changes were observed in the absolute number of GABA- and PV-IR cells. GABA-IR cells were more abundant in deprived animals than in control ones. In contrast, the number of PV-IR cells decreased significantly and PV immunoreactivity in dendrites and boutons was lower in deprived animals. These results suggest that the reduction in the number of PV-IR cells in olfactory-deprived lizards occurs without loss of GABA cells, and that PV expression is under the control of olfactory activity and remains plastic in the cerebral cortex of adult lizards.

Animals↗
PubMed1994

Depletion and recovery of the calcium-binding proteins calbindin and parvalbumin in the pigeon optic tectum following retinal lesions.

Retinal lesions in pigeons produced a marked depletion of somata and neuropil staining for both calbindin-D28k and parvalbumin immunoreactivities in the contralateral optic tectum. Calbindin-like immunoreactivity reappeared in some tectal layers by 6 weeks postlesion, whereas paravalbumin-like immunoreactivity recovered almost completely after 5 weeks. These data indicate that the retinal input may control the expression of calbindin and parvalbumin in the pigeon optic tectum.

Animals↗
PubMed1994

Chondroitin sulfate proteoglycan-immunoreactivity of lectin-labeled perineuronal nets around parvalbumin-containing neurons.

Perineuronal nets represent highly specialized glial and glia-associated structures. In this study, a triple fluorescence labeling of chondroitin sulfate proteoglycan-immunoreactive (CSPG-ir) and N-acetylgalactosamine (GalNac)-specific plant lectin Wisteria floribunda agglutinin (WFA) binding net components as well as parvalbumin-immunoreactivity (-ir) was performed. It was shown in the rat cortex, that the same nets frequently surrounding parvalbumin-ir neurons are stained by CSPG-ir as well as by the lectin binding method.

Animals↗