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At least 127 records · Page 7Linked to original sources
PubMed2006

Parvalbumin and calbindin D-28k immunoreactivity in transgenic mice with a G93A mutant SOD1 gene.

Immunohistochemical study was performed to examine if calcium-binding proteins are involved in the degeneration of motor neurons in the brain stems and the spinal cords of transgenic mice carrying a G93A mutant human SOD1 gene. Specimens from age-matched non-transgenic wild-type mice served as controls. In the spinal cord of the controls, the density of parvalbumin-immunoreactive neurons was highest in the large anterior horn neurons and lower in the posterior horn neurons in the spinal cord. On the other hand, calbindin D-28k immunoreactivity was much less apparent than that observed with parvalbumin antisera. Rexed's lamina II was densely immunostained for calbindin D-28k, whereas, in the anterior horn, calbindin-D-28k-positive small neurons were barely dispersed in a scattered pattern. In transgenic mice, parvalbumin-positive anterior horn neurons were severely reduced, even at the presymptomatic stage, whereas calbindin-positive neurons were largely preserved. At the symptomatic stage, both parvalbumin and calbindin D-28k immunoreactivity markedly diminished or disappeared in the anterior horn. Immunoblotting analysis revealed a significant reduction of immunoreactivity to parvalbumin antibody in transgenic mice compared with the controls. In the brain stem, parvalbumin-positive oculomotor and abducens neurons and the calbindin D-28k-positive sixth nucleus were well-preserved in transgenic mice as well as in the controls. Thus, the diffuse and severe loss of parvalbumin immunoreactivity of large motor neurons even at early stages in SOD1-transgenic mice and the absence of calbindin D-28k immunoreactivity of normal large motor neurons suggest that these calcium-binding proteins may contribute to selective vulnerability and an early loss of function of large motor neurons in this SOD1-transgenic mouse model.

Abducens Nerve↗
PubMed2004

Ontogeny of two calcium-binding proteins (calbindin D-28K and parvalbumin) in the human inferior olivary complex and their distribution in the adults.

The inferior olivary complex (IOC) is a prominent nuclear relay system of the medulla oblongata. Anatomically, it is connected to the cerebellum for coordination of motor activities. Calbindin D-28K (CALB) and parvalbumin (PV) are cytosolic calcium-binding proteins (CBP) that play a role in Ca2+ homeostasis. We examined their ontogeny and distribution in the fetal, postnatal and adult human IOC by immunohistochemistry. At 11-12 weeks of gestation (wg), calbindin immunoreactivity was present in the principal olive and the medial accessory olive, it was absent in the dorsal olive. Parvalbumin immunoreactivity developed at 16-17 wg in the ventral lamella and the lateral bulge of the principal olive only. Calbindin expression gradually increased from 20 to 37 wg, whilst by contrast, parvalbumin expression was moderate. By 37 wg, all three IOC subnuclei were immunopositive for both proteins. In a 3-month-old infant, parvalbumin was intensely developed in the olivary axons. In the adults (40- to 59-year-old), calbindin was distributed in most neurons, and olivocerebellar fibres, whereas parvalbumin was present in some neurons and few fibres. Parvalbumin expressed till 51 years, and disappeared by 59 years of age. Calbindin immunoreactivity in the olivary axons was declined at 70 years of age. The data suggest a differential distribution and requirement of these proteins in the human IOC maturation. It may be that the IOC utilizes mainly calbindin for Ca2+ buffering. The loss of parvalbumin with ageing might influence the excitability of the spared IOC neurons.

Adult↗
PubMed1998

Parvalbumin immunoreactivity during the development of the cerebellum of the rainbow trout.

The distribution of parvalbumin immunoreactivity in the developing cerebellum of the rainbow trout was studied by using a specific monoclonal antibody and the avidin-biotin peroxidase method. Parvalbumin immunoreactivity was absent during the embryonic development of the cerebellum. The first immunoreactive elements, identified by their localization and posterior morphological evolution as immature Purkinje cells, appeared at 6 days posthatching in the presumptive corpus cerebelli and lobus vestibulolateralis. The labeling extended throughout the cerebellum following a caudorostral gradient, and in 21 days alevins, parvalbumin immunoreactive Purkinje cells were also observed in the valvula cerebelli. The appearance of parvalbumin-immunostaining in the Purkinje cells was not simultaneous; the labeling was observed initially in the cell body, extending gradually to the dendritic branches and finally to the axon. From 1 year onwards, parvalbumin immunoreactive terminal puncta from the Purkinje cell axons were observed surrounding the cell bodies of eurydendroid cells, that were parvalbumin immunonegative in all developmental stages studied. The spatio-temporal pattern of parvalbumin immunoreactivity in the rainbow trout cerebellum is different to previous observations in the cerebellum of amniotes.

Animals↗
PubMed2002

Effect of Brn-3a deficiency on parvalbumin-, calbindin D-28k-, calretinin- and calcitonin gene-related peptide-immunoreactive primary sensory neurons in the trigeminal ganglion.

Immunohistochemistry for parvalbumin, calbindin D-28k, calretinin and calcitonin gene-related peptide (CGRP) was performed on the trigeminal ganglion and oro-facial tissues in Brn-3a wildtype and knockout mice at embryonic day 18.5 and postnatal day 0. In wildtype mice, the trigeminal ganglion contained abundant parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while the ganglion was almost devoid of calretinin-immunoreactive neurons. In Brn-3a knockout mice, a 63% decrease of parvalbumin-immunoreactive neurons was detected. In contrast, the absence of Brn-3a dramatically increased the number of calbindin D-28k-immunoreactive (3.5-fold increase) and calretinin-immunoreactive neurons (91-fold increase). The number of CGRP-immunoreactive neurons, however, was not altered by the Brn-3a deficiency. Cell size analysis indicated that loss of Brn-3a increased the proportions of small (<100 microm (2)) parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while it decreased those of large (>200 microm(2)) immunoreactive cells. Calretinin-immunoreactive neurons were either small or medium (100-200 microm (2)) in mutant mice. The oro-facial tissues contained parvalbumin-, calbindin D-28k- and CGRP-immunoreactive fibers, but not calretinin-immunoreactive ones in wildtype mice. In Brn-3a knockout mice, the number of parvalbumin-immunoreactive fibers markedly decreased in the infraorbital nerve and parvalbumin-immunoreactive endings disappeared in the vibrissa. In contrast, the number of calbindin D-28k-immunoreactive fibers increased significantly in the infraorbital and mental nerves. In addition, calbindin D-28k-immunoreactive endings appeared in the vibrissa. As well, some fibers showed calretinin-immunoreactivity in the infraorbital nerve of the mutant. However, no obvious change of CGRP-immunoreactive fibers was observed in the oro-facial region of knockout mice. Taken together, our data suggest that Brn-3a deficiency has effects on the expression of neurochemical substances in the trigeminal ganglion.

Animals↗
PubMed2000

Postnatal development of parvalbumin and calbindin D-28k immunoreactivities in the canine hippocampus.

The calcium-binding proteins, parvalbumin and calbindin D-28k, are markers of different classes of GABAergic interneurons and display different functions. The present study was attempted to determine immunoreactivities and colocalization of the parvalbumin and calbindin D-28k in the developing canine hippocampus by immunohistochemistry. The calcium-binding protein-containing neurons showed different developmental patterns. The first appearance of parvalbumin immunoreactive nonpyramidal cells was observed at P7. Parvalbumin immunoreactivity was elicited by the sequence from CA3 to CA1 to reach an adult-like distribution pattern, which was reached at P60, while calbindin D-28k immunoreactivity appeared from P0, including pyramidal and nonpyramidal cells. The characteristic distribution of calbindin D-28k immunoreactive pyramidal cells was clarified by P28, and an adult-like distribution pattern was reached by the end of the second postnatal month. Double-labeled nonpyramidal cells were frequently seen in the subareas, CA3 of P14/CA1-CA2 of P28, where parvalbumin immunoreactive nonpyramidal cells were emerging. These data suggest that the colocalization of the two calcium-binding proteins during development is related closely to the area-specific maturation of parvalbumin expression, although either prenatal expression of calbindin D-28k or parvalbumin was not determined.

Animals↗
PubMed2003

Consequence of parvalbumin deficiency in the mdx mouse: histological, biochemical and mechanical phenotype of a new double mutant.

We tested the hypothesis whether the mild dystrophy in mdx mice could result from the contribution of the cytosolic calcium buffer parvalbumin in maintaining a normal cytosolic [Ca2+]i, in spite of an increased passive Ca2+ influx. By crossing mdx mice with parvalbumin-deficient mice, double mutant mice, lacking both dystrophin and parvalbumin, were obtained. Though resting cytosolic [Ca2+]i and total calcium content were similar to that of mdx muscles, this new animal model presented a slightly more severe phenotype than the mdx mouse. Muscle pseudo-hypertrophy, the density of myotubes and of centronucleated fibres as well as the loss of IIB fibres were all increased in parvalbumin-deficient mdx mice. Many of these deficits were overcome in late adulthood, albeit fibrosis was clearly more pronounced than in mdx muscles. At 90 days, parvalbumin-deficient mdx mice showed higher levels of creatine phosphokinase and lower muscle strength, in vivo, than mdx mice. Isometric tension of isolated muscle was reduced, but the susceptibility to eccentric contraction was not increased. The slight aggravation of muscle dystrophy observed in mdx mice deprived of parvalbumin cannot explain the severity of the affection observed in xmd dogs and Duchenne dystrophy patients where parvalbumin is constitutively not expressed.

Age Factors↗
PubMed1983

Two new bifunctional protein modification reagents and their application to the study of parvalbumin.

2-[(Trifluoroacetoxy)mercuri]-4-fluorophenol (MFP) and 4-(acetoxymercuri)phenyl azide (MPA) have been prepared and characterized. The sulfhydryl-specific reagents MFP and MPA have been used to study the structure of parvalbumin. The 19F resonance of the derivative of parvalbumin with MFP was studied at 94.6 and 235.2 MHz. At 94.6 MHz, the 19F signal line width is 25 Hz and T1 = 0.28 s, while at 235.2 MHz, the line width is 35 Hz and T1 = 0.39 s. T1 was not affected by substitution of D2O for H2O as a solvent. Removal of calcium from the parvalbumin derivative resulted in the upfield shift of the 19F signal and a decrease in T1 at 94.6 MHz. The pKa for phenolic titration of the MFP derivative was 10.75 compared with 9.5 for the free reagent. These results are interpreted in terms of lodgment of the aryl group in a cleft in the surface of the parvalbumin. The derivative with MPA was photolyzed and subjected to amino acid analysis. Comparison of the analysis of parvalbumin, parvalbumin-MPA, and the photolyzed product indicated destruction of aspartic acid during the photolysis. Asp-22 is a reasonable candidate for the residue attacked, based on comparison with the published crystal structure of parvalbumin.

Animals↗
PubMed2002

Severe IgE-mediated anaphylaxis following consumption of fried frog legs: definition of alpha-parvalbumin as the allergen in cause.

BACKGROUND: IgE-mediated allergic reactions to bullfrog and edible frog have been reported. The implicated allergens have not been defined so far. The frog material and the patient's serum from a case of severe food-induced anaphylaxis were used to define the implicated allergen at the protein and DNA level. METHODS: Immunoblotting techniques and N-terminal protein microsequencing were used to define the allergen recognized by the patient's serum. Back translation from the identified protein sequence was used to design degenerated primers to amplify the allergen's cDNA by polymerase chain reaction (PCR). We defined the nucleotide sequence of the allergen from the frog of Indonesian origin that was consumed by the patient, and the homologous cDNA from Rana esculenta. RESULTS: Protein microsequencing revealed that the implicated frog allergen belonged to the parvalbumin family. cDNAs coding for alpha- and beta-parvalbumin of R. esculenta and Rana species were cloned. Recombinant proteins were expressed in Escherichia coli. The patient's serum IgE antibodies recognized parvalbumin prepared from frog muscle and recombinant alpha-parvalbumin from R. species but not from R. esculenta. Recombinant beta-parvalbumin was not recognized by the IgE antibodies. CONCLUSION: This work defines at the protein and DNA levels alpha-parvalbumin as the allergen implicated in a case of IgE-mediated anaphylaxis to frog muscle. It also shows that a protein belonging to the parvalbumin family is implicated in type I allergies outside the fish species.

Allergens↗
PubMed1982

Correlation of parvalbumin concentration with relaxation speed in mammalian muscles.

The physiological role of the Ca2+-binding protein parvalbumin in skeletal muscle has been investigated by measuring the parvalbumin content by HPLC in a variety of mammalian muscles, including man, and comparing the results with the respective muscle relaxation properties and fiber type compositions. The parvalbumin concentrations were highest in the skeletal muscles of the smallest animal investigated (mouse, gastrocnemius: 4.9 g/kg), which has the highest relaxation speed, and lowest in the larger animals (horse, deep gluteal muscle: less than or equal to 0.001 g/kg) and man (vastus, triceps: less than or equal to 0.001 g/kg), which have much lower relaxation speeds. Analysis of three type-homogeneous muscles of the guinea pig revealed highest parvalbumin concentrations (0.25 g/kg) in sartorius (type IIB) and lowest concentrations (less than or equal to 0.007 g/kg) in soleus (type I), consistent with the different half-relaxation times of fast and slow muscles. Denervation of the rat extensor digitorum longus, which increases the half-relaxation time from 9.4 to 19 msec, resulted in a 20% decrease of the parvalbumin content. Given this close correlation between parvalbumin content and relaxation speed in a variety of muscles and species, we suggest that parvalbumin is involved directly in the relaxation process in fast muscles.

Animals↗
PubMed1985

Relationship between the concentration of myoglobin and parvalbumin in various types of muscle tissues from chickens.

The concentration of parvalbumin was determined in various types of chicken muscle by immunological analysis and was compared with that of myoglobin. Parvalbumin was present specifically in skeletal muscle and absent in cardiac and gizzard muscle; exceptionally, neither parvalbumin nor myoglobin was detected in white breast muscle. The wing and leg red muscles, which had larger amounts of myoglobin, contained smaller quantities of parvalbumin. In these muscles, the concentration of parvalbumin was inversely related to that of myoglobin (correlation coefficient = -0.69). Both myoglobin and parvalbumin were observed in the legs of 18-d-old embryos; the parvalbumin content exceeded that of myoglobin until the birds were 4 to 6 weeks old, but the relationship was reversed thereafter. Myoglobin in gizzard muscle was present in 18-d-old embryos and increased markedly at hatching; it was already present in cardiac muscle at an early embryonic stage, increasing gradually until 14 weeks after hatching.

Age Factors↗
PubMed2002

Molecular dynamics study of Ca(2+) binding loop variants of silver hake parvalbumin with aspartic acid at the "gateway" position.

The helix-loop-helix (i.e., EF-hand) Ca(2+) ion binding motif is characteristic of a large family of high-affinity calcium ion binding proteins, including the parvalbumins, oncomodulins and calmodulins. In this work we describe a set of molecular dynamics computations on the major parvalbumin from the silver hake (SHPV-B) and on functional fragments of this protein, consisting of the first four helical regions (the ABCD fragment), and the internal helix-loop- helix region (the CD fragment). In both whole protein and protein fragments (i.e., ABCD and CD fragments), the 9th loop residue in the calcium ion binding site in the CD helix-loop-helix region (the so-called "gateway" position) has been mutated from glutamic acid to aspartic acid. Aspartic acid is one of the most common residues found at the gateway position in other (non-parvalbumin) EF- hand proteins, but has never been found at the gateway position of any parvalbumin. (Interestingly, aspartic acid does occur at the gateway position in the closely related rat and human oncomodulins.) Consistent with experimental observations, the results of our molecular dynamics simulations show that incorporation of aspartic acid at the gateway position is very disruptive to the structural integrity of the calcium ion coordination site in the whole protein. The aspartic acid mutation is somewhat less disruptive to the calcium ion coordination sites in the two parvalbumin fragments (i.e., the ABCD and CD fragments), presumably due to the higher degree of motional freedom allowable in these protein fragments. One problem associated with the E59D whole protein variant is a prohibitively close approach of the aspartate carboxyl group to the CD calcium ion observed in the energy-minimized (pre-molecular dynamics) structure. This steric situation does not emerge during energy-minimization of the wild-type protein. The damage to the structural integrity of the calcium ion coordination site in the whole protein E59D variant is not relieved during the molecular dynamics simulation. In fact, during the course of the 300 picosecond simulation, all of the calcium ion ligands leave the primary coordination sphere. In addition, the conserved hydrogen- bonds (in the short beta-sheet structure) that links the CD site to the symmetry-related EF site (in the non-mutated whole protein) is also somewhat disrupted in the E59D whole protein variant. These results suggest that the Ca(2+) ion binding deficiencies in the CD loop are related, at least in part, to the unique interaction that exists between the paired CD and EF hands in the whole protein. Our theoretical results correlate well with previous studies on engineered EF-hand proteins and with all of our experimental evidence on whole silver hake parvalbumin and enzymatically-generated parvalbumin fragments.

Amino Acid Motifs↗
PubMed1988

Opposite regulation of the mRNAs for parvalbumin and p19/6.8 in myotonic mouse muscle.

The gene mutation in the mouse, 'arrested development of righting response', adr, causes a defect of chloride conductance of the muscle fibre membrane leading to the symptoms of myotonia [Mehrke, G., Brinkmeier, H. and Jockusch, H. (1988) Muscle & Nerve 11, 440-446]. In fast muscle, the myotonic phenotype is accompanied by a drastic reduction of the Ca2+-binding protein, parvalbumin. Messenger RNA levels in organs of myotonic (ADR) mice were analysed. In fast muscles of the mutant, in-vitro-translatable parvalbumin mRNA was strongly reduced, whereas the mRNA for the slow-muscle-specific protein, p19/6.8, was increased. In contrast, the parvalbumin mRNA in the cerebellum was not affected by the adr mutation. A reduction of the two parvalbumin mRNA species (700 and 1100 nucleotides) in ADR fast muscle and unaltered parvalbumin mRNA levels in mutant cerebella were demonstrated by cDNA/mRNA hybridisation, using a rat parvalbumin cDNA as a probe. The mRNA level for another Ca2+-binding protein, calmodulin, was low in muscle and high in the central nervous system but was unaffected by the mutation. When adr/adr mice were fed a diet containing the membrane-stabilising drug, tocainide, the levels in muscle of the mRNAs for parvalbumin and p19/6.8 were partially normalised.

Animals↗
PubMed1990

Heat capacity and entropy changes of the major isotype of the toad (Bufo) parvalbumin induced by calcium binding.

The possible structural changes in the major isotype of parvalbumin from the toad (Bufo bufo japonicus) skeletal muscle caused by Ca2+ and Mg2+ binding have been analyzed by microcalorimetric titrations. Parvalbumin was titrated with Ca2+ in both the absence and presence of Mg2+ and with Mg2+ in the absence of Ca2+, at pH 7.0, and at 5 degrees, 15 degrees, and 25 degrees C. The two sites in a molecule were equivalent on Mg2(+)-Ca2+ exchange, but distinguishable on Ca2+ and Mg2+ binding. The reactions of parvalbumin with Ca2+ are exothermic at every temperature in both the absence and presence of Mg2+, but those with Mg2+ are always endothermic except for the binding to site 1 at 25 degrees C. The magnitudes of the hydrophobic and internal vibrational contributions to the heat capacity and entropy changes of parvalbumin on Ca2+ and Mg2+ binding and Mg2(+)-Ca2+ exchange have been estimated by the empirical method of Sturtevant [Sturtevant, J. M. (1977) Proc. Natl Acad. Sci. USA 74, 2236-2240]. Although no major conformational changes were noted between Ca2(+)- and Mg2(+)-bound forms of toad parvalbumin, the conformational difference was larger in Ca2+ (or Mg2+) binding to site 1 than site 2. This may indicate that the metal-free form is much less stable than any form with Ca2+ (or Mg2+) bound at one site at least. On Mg2(+)-Ca2+ exchange, the vibrational as well as hydrophobic entropy is only slightly increased in a parallel manner. In contrast, on Ca2+ (or Mg2+) binding, the hydrophobic entropy increases but the vibrational entropy decreases; the former indicates the sequestering of nonpolar groups from the surface to the interior of a molecule, and the latter suggests that the overall structures are tightened on Ca2+ (or Mg2+) binding but loosened on Mg2(+)-Ca2+ exchange. Despite the clear distinctions in the thermodynamic features, the conformational changes of toad parvalbumin are essentially the same as those of the two isotypes of bullfrog parvalbumins on Ca2+ binding and Mg2(+)-Ca2+ exchange.

Animals↗
PubMed2001

In vivo acceleration of heart relaxation performance by parvalbumin gene delivery.

Defective cardiac muscle relaxation plays a causal role in heart failure. Shown here is the new in vivo application of parvalbumin, a calcium-binding protein that facilitates ultrafast relaxation of specialized skeletal muscles. Parvalbumin is not naturally expressed in the heart. We show that parvalbumin gene transfer to the heart in vivo produces levels of parvalbumin characteristic of fast skeletal muscles, causes a physiologically relevant acceleration of heart relaxation performance in normal hearts, and enhances relaxation performance in an animal model of slowed cardiac muscle relaxation. Parvalbumin may offer the unique potential to correct defective relaxation in energetically compromised failing hearts because the relaxation-enhancement effect of parvalbumin arises from an ATP-independent mechanism. Additionally, parvalbumin gene transfer may provide a new therapeutic approach to correct cellular disturbances in calcium signaling pathways that cause abnormal growth or damage in the heart or other organs.

Animals↗
PubMed1999

Median raphe serotonergic innervation of medial septum/diagonal band of broca (MSDB) parvalbumin-containing neurons: possible involvement of the MSDB in the desynchronization of the hippocampal EEG.

Activation of median raphe serotonergic neurons results in the desynchronization of hippocampal electroencephalographic (EEG) activity. This could be a direct effect, because serotonin (5-HT) fibers terminate on a specific population of hippocampal interneurons. On the other hand, it could be an indirect action through the medial septum/diagonal band of Broca (MSDB) pacemaker cells, because, in addition to previously described inhibitory effects, excitatory actions of 5-HT have been demonstrated on MSDB gamma-aminobutyric acid (GABA)-containing neurons through 5-HT2A receptors. Electron microscopic double immunostaining for Phaseolus vulgaris-leucoagglutinin (PHA-L) injected into the median raphe (MR) and parvalbumin, choline acetyltransferase, or calretinin as well as double immunostaining for 5-HT and parvalbumin, and colocalization for parvalbumin and 5-HT2A receptors were done in rats. The results demonstrated that: 1) MR axons form perisomatic and peridendritic baskets and asymmetric synaptic contacts on MSDB parvalbumin neurons; 2) these fibers do not terminate on septal cholinergic and calretinin neurons; 3) 5-HT fibers form synapses identical to those formed by PHA-L-immunolabeled axons with parvalbumin neurons; and 4) MSDB parvalbumin cells contain 5-HT2A receptors. These observations indicate that 5-HT has a dual action on the activity of hippocampal principal cells: 1) an inhibition of the input sector by activation of hippocampal GABA neurons that terminate exclusively on apical dendrites of pyramidal cells, and 2) a disinhibition of the output sector of principal neurons. MSDB parvalbumin-containing GABAergic neurons specifically innervate hippocampal basket and chandelier cells. Thus, 5-HT-elicited activation of MSDB GABAergic neurons will result in a powerful inhibition of these GABA neurons.

Animals↗
PubMed1990

Comparison of metal ion-induced conformational changes in parvalbumin and oncomodulin as probed by the intrinsic fluorescence of tryptophan 102.

The calcium-induced conformational changes of the 108-amino acid residue proteins, cod III parvalbumin and oncomodulin, were compared using tryptophan as a sensitive spectroscopic probe. As native oncomodulin is devoid of tryptophan, site-specific mutagenesis was performed to create a mutant protein in which tryptophan was placed in the identical position (residue 102) as the single tryptophan residue in cod III parvalbumin. The results showed that in the region probed by tryptophan-102, cod III parvalbumin experienced significantly greater changes in conformation upon decalcification compared to the oncomodulin mutant, F102W. Addition of 1 eq of Ca2+ produced greater than 90% of the total fluorescence response in F102W, while in cod III parvalbumin, only 74% of the total was observed. Cod III parvalbumin displayed a negligible response upon Mg2+ addition. In contrast, F102W did respond to Mg2+, but the response was considerably less when compared to Ca2+ addition. Time-resolved fluorescence showed that the tryptophan in both proteins existed in at least two conformational states in the presence of Ca2+ and at least three conformational states in its absence. Comparison with quantum yield measurements indicated that the local electronic environment of the tryptophan was significantly different in the two proteins. Collectively, these results demonstrate that both cod III parvalbumin and oncomodulin undergo Ca2(+)-specific conformational changes. However, oncomodulin is distinct from cod III parvalbumin in terms of the electronic environment of the hydrophobic core, the magnitude of the Ca2(+)-induced conformational changes, and the number of calcium ions required to modulate the major conformational changes.

Amino Acid Sequence↗
PubMed1997

Distribution of parvalbumin-, calretinin-, and calbindin-D28k-immunoreactive neurons and fibers in the human entorhinal cortex.

Parvalbumin, calretinin, and calbindin-D28k are calcium-binding proteins that are located in largely nonoverlapping neuronal populations in the brain. The authors studied the distribution of parvalbumin-, calretinin-, and calbindin-D28k-immunoreactive (ir) cells, fibers, terminals, and neuropil in the eight subfields of the human entorhinal cortex. The distribution of each of the three calcium-binding proteins largely followed the cytoarchitectonic borders of the eight entorhinal subfields, although the regional and laminar distributions of the three proteins were segregated rather than overlapping. The highest density of parvalbumin-ir neurons and terminals was found in the caudal and lateral subfields of the entorhinal cortex. Calretinin and calbindin-D28k immunoreactivities were high rostromedially, although a large number of calretinin and calbindin-D28k neurons were also found in the caudal subfields. All parvalbumin-ir cells had a morphological appearance of nonpyramidal neurons. Parvalbumin-ir terminals formed basket-like formations around unstained somata and cartridges, suggesting that parvalbumin neurons compose a subpopulation of gamma-aminobutyric acid (GABA)ergic basket cells and chandelier cells, respectively. Although calretinin and calbindin-D28k were also found in numerous nonpyramidal neurons, both were also located in pyramidal-shaped neurons in layers V and VI (calretinin) and in layers II and III (calbindin) of the entorhinal cortex, suggesting that they play roles in projection neurons as well. Moreover, the high density of nonpyramidal neurons containing calcium-binding proteins in layers II and III of the entorhinal cortex suggests that they form an integral component of a network that controls the entorhinal outputs to the hippocampus. Furthermore, the largely nonoverlapping distributions of the parvalbumin-, calretinin-, and calbindin-ir neuronal populations in the entorhinal cortex indicate that each of them may modulate a different subset of topographically organized entorhinal outputs.

Adult↗
PubMed2000

Maternal morphine alters parvalbumin immunoreactivity patterns in neonatal mouse brain.

The influence of chronic maternal morphine on the parvalbumin immunoreactive patterns in developing mouse brain was studied. Female Swiss mice were administered daily saline or morphine (30 or 60 mg/kg) for a period of 7 days before mating, gestation, and 21 days postpartum. Their pups were sacrificed on postnatal day 18 and the brains were examined histologically and immunohistochemically for parvalbumin-positive neurons. Histological observations revealed no significant changes in the cell number of the morphine-exposed neonatal forebrain, whereas the number of parvalbumin-positive neurons increased in layers II-IV of the parietal cortex I. Moreover, the number of parvalbumin-positive dendrites increased remarkably in the cingulate and parietal I cortices of the morphine-exposed neonates, indicating the region-specific increase in the PV immunoreactive profiles. These results are consistent with the key roles played by the above brain regions in the altered behavioral patterns of the maternally addicted neonates, such as impaired somatosensory and cognitive performances. The mechanism of morphine action on parvalbumin expression in neonatal mouse brain is not evident, but alterations in the expression patterns of parvalbumin in specific regions of the developing brain might be one of the cellular mechanisms by which addictive drugs modify the functional aspects of the developing CNS.

Aging↗