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PubMed1995

Co-localization of somatostatin mRNA and parvalbumin in the dorsal rat hippocampus after cerebral ischemia.

Following transient global ischemia most of the neurons containing somatostatin in the fascia dentata of the dorsal hippocampal formation die, while somatostatinergic neurons in the CA1 region survive. The neurons react to ischemia with a transiently reduced expression of somatostatin mRNA and peptide. We have tested the hypothesis that this selective vulnerability is solely related to those somatostatinergic neurons which do not express the calcium-binding protein parvalbumin. Postischemic changes were studied in rat dorsal hippocampus at 2 and 16 days after 10 min of global cerebral ischemia using a four-vessel occlusion model. We performed a double-staining visualizing the mRNA coding for somatostatin by non-radioactive in situ hybridization and parvalbumin protein by immunocytochemistry. Only 5% of the somatostatinergic cells in the fascia dentata contained parvalbumin. The number of somatostatinergic cells was permanently reduced following ischemia. Among surviving neurons we found cells with and without parvalbumin expression. Thus, expression of parvalbumin is not predictive for survival of somatostatinergic cells in the fascia dentata. In contrast, in CA1, 37% of the somatostatinergic cells contained parvalbumin. These cells were unaffected by the transient ischemic period. The somatostatinergic cells lacking parvalbumin showed transiently reduced mRNA levels at day 2, but recovered to control values at the 16th postischemic day. Thus, expression of the calcium-buffering protein parvalbumin coincides with resistance of somatostatinergic neurons in CA1 to transient effects of ischemia. We conclude that the calcium-buffering capacity of parvalbumin may partially contribute to the protection of somatostatinergic neurons from ischemia in the dorsal hippocampus. However, the survival of somatostatinergic cells without parvalbumin indicates the importance of other factors as well.

Animals↗
PubMed1989

Parvalbumin genes from human and rat are identical in intron/exon organization and contain highly homologous regulatory elements and coding sequences.

The structural organization of the chromosomal gene for human parvalbumin was determined mostly by sequencing exons and intron exon junctions of a 7500 base-pair (bp) long genomic clone derived from a chromosome 22-specific gene library. Four exons coding for 100 from a total of 109 amino acids were detected in this clone and 472 bp of the 5'-flanking region were sequenced. The region corresponding to the C-terminal amino acids 101 to 109 of human parvalbumin was determined by sequencing a cDNA fragment derived from human brain mRNA after amplification by the polymerase chain reaction. The first intron is placed 7 bp upstream from the ATG translation start signal, whereas all other splice sites divide putative Ca2+-binding domains. All intron positions coincide exactly with those reported for the rat parvalbumin gene. The 5' mRNA leader sequence has a similarity of 57%, the coding region of 91% and the 3' non-coding region of 83% to the corresponding rat sequences. Only nine conservative amino acid replacements were observed between human and rat parvalbumins. The predicted secondary structures for human, rat, mouse and rabbit parvalbumins are very similar, indicating a strong structural relationship among mammalian parvalbumins. Several elements with potential transcription regulatory activities were found in the region immediately 5' to the transcription start site including a TATA box (TATATA) and a CAAT box (CCAAAAT). Several regions in the putative promoter are strongly conserved between the human and rat parvalbumin genes. One of these with a length of 32 bp is identical with the rat counterpart and has a high degree of homology to a promoter region in the myosin light chain 3F gene, which is expressed in fast contracting/relaxing muscle fibers (anaerobic/type IIb), the cell type that also exhibits highest levels of parvalbumin expression. The human parvalbumin mRNA contains the putative polyadenylation signal AATAAA 13 nucleotides upstream from the polyadenylation site. A 700-nucleotide long parvalbumin mRNA is synthesized at low levels in the human cerebellum as well as in the neuroblastoma cell line SK-N-BE.

Amino Acid Sequence↗
PubMed1990

Topographical localization of neurons containing parvalbumin and choline acetyltransferase in the medial septum-diagonal band region of the rat.

The normal morphology and distribution of parvalbumin-containing neurons (shown in a previous study to be GABAergic nerve cells) of the medial septal-diagonal band region of the adult rat brain have been studied, and the findings compared with observations on choline acetyltransferase-immunoreactive neurons. The two antigens were visualized either in the same sections using a double-label immunohistochemical procedure for the simultaneous localization of parvalbumin and choline acetyltransferase, or in immediately adjacent sections. In double-stained sections of the whole medial septal-diagonal band complex, about 34% of the total neurons showed immunoreactivity to parvalbumin; the proportion of parvalbumin-labelled neurons was slightly higher in the medial septal-vertical limb of the diagonal band region, and much lower in the horizontal limb of the diagonal band region. The distribution of parvalbumin- and choline acetyltransferase-containing neurons also varied markedly between different mediolateral subdivisions of the medial septum: about 30, 65 and 2% of the parvalbumin-immunoreactive neurons were present in the midline, medial and lateral part of the medial septum, respectively. At different rostrocaudal levels, the proportion of parvalbumin- and choline acetyltransferase-positive neurons varied in a consistent manner, and the largest number of parvalbumin-containing neurons was found at the level 1.9 mm anterior to the bregma. In the absence of reliable immunocytochemical methods for the localization of glutamate decarboxylase and GABA, parvalbumin may serve as a good marker for studying the distribution of GABAergic neurons in the medial septum-diagonal band region. Moreover, the precise maps reported in the present study of the topographic localization of parvalbumin-containing GABAergic and choline acetyltransferase-immunoreactive cholinergic nerve cells in the medial septal-diagonal band complex will serve as a useful guide in future morphological and electrophysiological studies on the septum and its efferents.

Albumins↗
PubMed1996

Alpha-parvalbumin reduces depolarization-induced elevations of cytosolic free calcium in human neuroblastoma cells.

We investigated whether the expression of human alpha-parvalbumin affects depolarization-induced elevations of the cytosolic free calcium concentration ([Ca2+]i) in human neuroblastoma SKNBE2 cells. A full length human parvalbumin cDNA was cloned by PCR from human cerebellum and transiently transfected into SKNBE2 cells. Immunofluorescence staining using an antibody raised against parvalbumin revealed a transfection efficacy of about 14%. In parvalbumin-expressing SKNBE2 cells, parvalbumin concentration determined by quantitative Western blotting amounted to 0.42 mM. Transfected SKNBE2 cells were depolarized for 2 min by 50 mM K+. During this period, [Ca2+]i was monitored by video microfluorimetry using the Ca2+ indicator Fura-2. In a fraction of cells, depolarization induced a transient elevation in [Ca2+]i. The size of this elevation was compared with the immunofluorimetrically determined expression of parvalbumin on a cell-to-cell basis. Cells with a significant parvalbumin immunofluorescence responded to depolarization with smaller elevations in [Ca2+]i than non-parvalbumin-expressing cells. Resting [Ca2+]i did not differ between parvalbumin-expressing and control cells. These observations indicate that large depolarization-induced transient elevations of [Ca2+]i in neuroblastoma cells can be suppressed by parvalbumin.

Animals↗
PubMed2001

Parvalbumin-containing neurons in the rat basolateral amygdala: morphology and co-localization of Calbindin-D(28k).

Parvalbumin is a calcium-binding protein that is contained in certain neuronal populations in the brain. Although the exact function of parvalbumin is not clear, it has been found to be a useful marker for studying the connections of specific cell types in immunohistochemical studies. In the present investigation immunohistochemical techniques were used to study the morphology of parvalbumin-containing neurons in the rat basolateral amygdala. These neurons were found to be a morphologically heterogeneous subpopulation of non-pyramidal interneurons. Parvalbumin-positive axons in the basolateral amygdala were observed to form "pericellular baskets" that enveloped the perikarya of pyramidal neurons. In addition, some parvalbumin-immunoreactive axons formed "cartridges" that appeared to surround non-immunoreactive processes. The morphology of parvalbumin-positive neurons closely resembled that of neurons containing calbindin, a related calcium-binding protein. Analysis of adjacent sections stained for each protein using the mirror technique revealed that approximately 80% of parvalbumin neurons also contained calbindin, and that approximately 60% of calbindin neurons also contained parvalbumin. This study demonstrates that parvalbumin-containing neurons constitute an important subpopulation of non-pyramidal interneurons in the rat basolateral amygdala. The axonal configurations of these cells indicate that they may exert a potent inhibitory influence over pyramidal projection neurons. We suggest that parvalbumin-containing neurons can control emotional responses mediated by the basolateral amygdala by controlling the output from this important brain region.

Amygdala↗
PubMed2001

Parvalbumin and calbindin are differentially distributed within primary and secondary subregions of the mouse auditory forebrain.

The calcium binding proteins parvalbumin and calbindin are thought to differentially regulate physiological functions and often show complementary distributions in the CNS. Our goal was to determine parvalbumin and calbindin distributions in the different subdivisions of mouse auditory thalamus and auditory cortex. Following fixation, FVB mouse brains (postnatal days 38-80) were sectioned along coronal and horizontal planes, then processed for parvalbumin and calbindin immunohistochemistry (antibodies: parvalbumin pa-235, calbindin-d-28k cl-300). Strong complementary differences in calcium binding protein distributions were found in mouse auditory thalamus. The ventral division of the medial geniculate, which is the principal relay to primary auditory cortex, exhibited dense parvalbumin but weak calbindin immunoreactivity. In contrast, most of the 'secondary' auditory thalamic regions surrounding the ventral division showed strong calbindin and lighter parvalbumin levels. Thus, the mouse auditory thalamus is composed of a parvalbumin positive 'core' surrounded by a calbindin positive 'shell'. Parvalbumin immunoreactivity was also more prominent in the primary auditory cortex than in the secondary belt auditory cortex. Calbindin immunoreactivity in auditory cortex was less clearly divided along primary/secondary lines, especially in supragranular layers. However, within infragranular layers, there was heavier staining in belt areas than in primary auditory cortex. In auditory thalamus, parvalbumin labeling was largely confined to the neuropil, whereas calbindin labeling involved somata and neuropil. In auditory cortex, somata and neuropil were positive for both proteins.In summary, the calcium binding proteins parvalbumin and calbindin were found to be differentially distributed within the primary and non-primary regions of mouse auditory forebrain. These differences in protein distribution may contribute to the distinct types of physiological responses that occur in the primary vs. non-primary areas.

Animals↗
PubMed1997

Parvalbumin-immunoreactive neurons in the hippocampal formation of Alzheimer's diseased brain.

The number and topographic distribution of immunocytochemically stained parvalbumin interneurons was determined in the hippocampal formation of control and Alzheimer's diseased brain. In control hippocampus, parvalbumin interneurons were aspiny and pleomorphic, with extensive dendritic arbors. In dentate gyrus, parvalbumin cells, as well as a dense plexus of fibers and puncta, were associated with the granule cell layer. A few cells also occupied the molecular layer. In strata oriens and pyramidale of CA1-CA3 subfields, parvalbumin neurons gave rise to dendrites that extended into adjacent strata. Densely stained puncta and beaded fibers occupied stratum pyramidale, with less dense staining in adjacent strata oriens and radiatum. Virtually no parvalbumin profiles were observed in stratum lacunosum-moleculare or the alveus. Numerous polymorphic parvalbumin neurons and a dense plexus of fibers and puncta characterized the deep layer of the subiculum and the lamina principalis externa of the presubiculum. In Alzheimer's diseased hippocampus, there was an approximate 60% decrease in the number of parvalbumin interneurons in the dentate gyrus/CA4 subfield (P<0.01) and subfields CA1-CA2 (P<0.01). In contrast, parvalbumin neurons did not statistically decline in subfields CA3, subiculum or presubiculum in Alzheimer's diseased brains relative to controls. Concurrent staining with Thioflavin-S histochemistry did not reveal degenerative changes within parvalbumin-stained profiles. These findings reveal that parvalbumin interneurons within specific hippocampal subfields are selectively vulnerable in Alzheimer's disease. This vulnerability may be related to their differential connectivity, e.g., those regions connectionally related to the cerebral cortex (dentate gyrus and CA1) are more vulnerable than those regions connectionally related to subcortical loci (subiculum and presubiculum).

Adult↗
PubMed1999

Parvalbumin-immunoreactive, fast-spiking neurons in the medial septum/diagonal band complex of the rat: intracellular recordings in vitro.

The medial septum/diagonal band complex is composed predominantly of cholinergic and GABAergic neurons, and it projects to the hippocampal formation. A proportion of the GABAergic neurons contain parvalbumin, a calcium-binding protein that has previously been localized in fast-spiking, non-accommodating GABAergic neurons in the cerebral cortex and neostriatum. The aim of the present study was to determine whether parvalbumin is localized preferentially in a similar electrophysiological class of neuron in the medial septum/diagonal band complex. The study was carried out using in vitro intracellular recording, intracellular biocytin filling and parvalbumin immunocytochemistry. Three main classes of neurons were identified according to standard criteria: burst-firing, slow-firing and fast-firing neuronal populations. The fast-firing neurons were subdivided into two subpopulations based on whether or not they displayed accommodation. The fast-spiking, non-accommodating cells were furthermore found to be spontaneously active at resting potentials, and to possess action potentials of significantly (P < 0.05) shorter duration (half width: 0.61 +/- 0.12 ms) than those of the regular-spiking, accommodating neurons (1.0 +/- 0.34 ms). Of the neurons that were successfully filled with biocytin and processed for parvalbumin immunoreactivity, 82% of the fast-spiking, non-accommodating cells possessed parvalbumin immunoreactivity, while none of the regular-spiking, accommodating neurons were found to be immunoreactive for parvalbumin. The slow-firing neurons, shown previously to be cholinergic, did not stain for parvalbumin immunoreactivity, in agreement with studies showing parvalbumin to be localized solely in GABAergic neurons in the medial septum/diagonal band complex. In conclusion, these findings suggest the presence of a previously uncharacterized population of neurons in the medial septum/diagonal band complex that generate high-frequency, non-adaptive discharge. This property correlates with the localization of parvalbumin in these neurons, which suggests that parvalbumin fulfils the same role in the medial septum/diagonal band complex that it does in other parts of the brain. The fast-spiking neurons in the medial septum/diagonal band complex may play an essential role in the GABAergic influence of the septum on the hippocampal formation.

Action Potentials↗
PubMed1999

Illusive transience of parvalbumin expression during embryonic development of the primate spinal cord.

Parvalbumin has been located by pre-embedding light- and electron microscopic immunohistochemical techniques in the spinal cords of monkey fetuses (Macaca fasciculata), ranging from E70 to E 123, and in young (P20) and young adult (3 years) Macaque monkeys. During the time window investigated, the main developmental events of parvalbumin-containing neural elements are that parvalbumin-positive dorsal root collaterals establish intercellular networks first around nerve cells of Clarke's nucleus, then in the motoneuron pool and finally in the upper dorsal horn. In each of these areas, location of the parvalbumin-positive network is gradually shifted from medial to lateral. Whenever an intercellular network is established, nerve cells innervated by parvalbumin-positive terminals of dorsal root collaterals start to express parvalbumin. Immunoreactivity of dorsal root axons is transient; it disappears first from the intercellular networks and, afterwards, also from the dorsal columns. However, the pericellular synaptic terminals and their post-synaptic nerve cells express parvalbumin into adulthood. It is concluded that some of the large (Type A) dorsal root ganglion cells are the first ones in the spinal reflex pathway to express parvalbumin, which is elicited and gradually increased in nerve cells synaptically innervated by parvalbumin-positive axon terminals. This seems to represent a specific case of activation (or desinhibiton) of the genome. Apparent "transience" of parvalbumin is due to the specific geometry of primary sensory neurons equipped with extremely long axonal processes, and the consequent specialities of axonal transport characteristics.

Animals↗
PubMed1999

Parvalbumin concentration and diffusion coefficient in frog myoplasm.

The concentrations and diffusivity of two isoforms of parvalbumin, IVa and IVb, were measured using quantitative SDS PAGE in single fibers from semitendinosus muscles of the frog Rana temporaria. The concentrations of IVa and IVb were 2.9 +/- 0.3 (SEM) and 4.5 +/- 0.5 g l-1 total fiber volume, respectively. The total concentration of parvalbumin (7.4 +/- 0.8 g l-1 total fiber) corresponds to a cytosolic concentration of 0.9 +/- 0.1 mmol l-1 myoplasmic water. Estimates for the transverse and longitudinal diffusion coefficients for parvalbumin at 4 degrees C were obtained in two ways: (1) by diffusion of parvalbumin out of skinned fibers into droplets of relaxing solution, and (2) by diffusion of parvalbumin between two juxtaposed skinned fibers under oil. The transverse diffusion coefficient obtained using the droplet method was significantly lower than that obtained using juxtaposed fibers, but the longitudinal diffusion coefficients obtained from both methods were similar. The juxtaposed fiber method more accurately approximates parvalbumin diffusion in undisturbed myoplasm because no artificial solutions were used and, upon fiber-to-fiber contact, a potentially confounding oil barrier at the interface rapidly disperses. The juxtaposed fiber method yielded values for transverse (4.27 +/- 0.87 x 10(-7) cm2 s-1) and longitudinal (3.20 +/- 0.74 x 10(-7) cm2 s-1) diffusion coefficients that were not significantly different, suggesting that diffusion of parvalbumin in myoplasm is essentially isotropic. The average diffusion coefficient of frog parvalbumin in myoplasm (3.74 +/- 0.81 x 10(-7) cm2 s-1; 4 degrees C) is approximately a third of that estimated for frog parvalbumin diffusing in bulk water into and out of 3% agarose cylinders (10.6 x 10(-7) cm2 s-1; 4 degrees C). The reduced translational mobility of parvalbumin in myoplasm reflects an elevated effective viscosity due to tortuosity and viscous drag imposed by the fixed proteins of the cytomatrix and the numerous diffusible particles of the cytosol.

Animals↗
PubMedDate not supplied

Parvalbumin in respiratory neurons of the ventrolateral medulla of the adult rat.

A column of parvalbumin immunoreactive neurons is closely associated with the location of respiratory neurons in the ventrolateral medulla of the rat. The majority (66%) of bulbospinal neurons in the medullary ventral respiratory column (VRC) that were retrogradely labeled by tracer injections in the phrenic nucleus were also positive for parvalbumin. In contrast, only 18.8% of VRC neurons retrogradely labeled after a tracer injection in the VRC, also expressed parvalbumin. The average cross-sectional area of VRC neurons retrogradely labeled after VRC injections was 193.8 microm2 +/- 6.6 SE. These were significantly smaller than VRC parvalbumin neurons (271.9 microm2 +/- 12.3 SE). Parvalbumin neurons were found in the Bötzinger Complex, the rostral ventral respiratory group (VRG), and the caudal VRG, areas which all contribute to the bulbospinal projection. In contrast, parvalbumin neurons were sparse or absent in the preBötzinger Complex and in the vicinity of the retrotrapezoid nucleus, areas that have few bulbospinal projections. Parvalbumin was rarely colocalized within Neurokinin-1 receptor positive (NK1R) VRC neurons, which are found in the preBötzinger complex and in the anteroventral part of the rostral VRG. Parvalbumin neurons in the Bötzinger Complex and rostral VRG help define the rostrocaudal extent of these regions. The absence of parvalbumin neurons from the intervening preBötzinger complex also helps establish the boundaries of this region. Regional boundaries described in this manner are in good agreement with earlier physiological and anatomical studies. Taken together, the distributions of parvalbumin, NK1R and bulbospinal neurons suggest that the rostral VRG may be subdivided into distinct, anterodorsal, anteroventral, and posterior subdivisions.

Animals↗
PubMed2004

A parvalbumin-containing, axosomatic synaptic network in the rat medial septum: relevance to rhythmogenesis.

The medial septal diagonal band complex (MS/DB), made up of cholinergic and GABAergic neurons, plays an important role in the generation of the hippocampal theta rhythm. A GABAergic neuron type in the MS/DB that has fast spiking properties was shown previously to contain parvalbumin immunoreactivity and to form axosomatic connections with unidentified somata. The aim in the current study was to determine the neurochemical identities of these target neurons. In slices and in perfused-fixed brain, staining for parvalbumin immunoreactivity first of all revealed the presence of two types of parvalbumin-positive somata in the MS/DB: medially located neurons with parvalbumin-positive basket-like terminals on them, and more laterally located neurons with fewer parvalbumin-positive contacts on them. In MS/DB slices, the terminals of fast spiking neurons filled with biocytin correspondingly made either numerous contacts that surrounded the parvalbumin-positive cell body in basket-like formation, or 1-5 contacts on a localized patch of the soma. These contacts were shown by electron microscopy to form synaptic junctions. No terminals of biocytin-filled fast spiking neurons were observed on cholinergic neurons, and dual staining in perfused-fixed brain did not reveal the presence of parvalbumin-containing terminals on cholinergic somata. Our results suggest therefore that there are two subtypes of parvalbumin-containing neuron in the MS/DB, and that these are interconnected via axosomatic synapses. The contrasting topographical organization of the two types of parvalbumin-containing neuron suggests that they may receive different types of afferent input, but this will require substantiation in future studies. We propose that generation of rhythmic activity in the MS/DB is controlled by contrasting contributions from two types of parvalbumin-positive neuron, and that the role of the cholinergic neuron is modulatory.

Action Potentials↗
PubMed1994

Parvalbumin immunohistochemistry in denervated skeletal muscle.

Parvalbumin is a calcium-binding protein which, in muscle, is mainly found in type 2B fibres, whereas type 1 fibres lack parvalbumin immunoreactivity. Previous studies have shown that this pattern is highly dependent upon motor neuron innervation and is modified in denervated, cross-reinnervated or chronic low-frequency stimulated muscles. In the present study, we have examined the modifications of parvalbumin immunocytochemistry in the anterior tibialis muscle of the rat at different intervals following section of the sciatic nerve. During the first 2 weeks after denervation, no changes in parvalbumin immunoreactivity were seen, although a global reduction of fibre diameter was observed. Three weeks after denervation, small angulated, strongly parvalbumin-immunoreactive fibres appeared. From the second month onwards, the pattern of parvalbumin immunohistochemistry was characterized by areas composed of small, strongly immunoreactive fibres separated by less atrophic areas displaying a normal chequerboard distribution of parvalbumin immunoreactivity. The increase of parvalbumin-immunoreactivity in denervated and reinnervated muscle, as seen in our study, indicates that important changes in parvalbumin distribution occurs in muscle fibres after denervation. These changes are probably produced in an attempt to bind the free cytosolic calcium which accumulates in denervated fibres, and further reinforces the role of parvalbumin in calcium homeostasis during denervation and reinnervation.

Adenosine Triphosphatases↗
PubMed1986

Parvalbumin in cat brain: isolation, characterization, and localization.

Because of the increasing evidence that Ca2+-binding proteins have important regulating functions in nerve cells and because of the indications that there are species differences in the structures of these proteins, parvalbumin was purified from cat brain and muscle. Brain and muscle parvalbumins were found to be indistinguishable from each other in their biochemical and immunological properties. However, cat parvalbumin differs from all other mammalian parvalbumins by its apparently lower Mr on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of 10-11K (compared to rat parvalbumin, 12K), and a lower pI of 4.6 (rat parvalbumin, 4.9), in the tryptic peptide maps, and in the immunological properties, indicating a distinct primary structure. With the purified parvalbumin as antigen, polyclonal antibodies were raised in rabbits and these were subsequently used for immunohistochemical localizations of parvalbumin in the cat brain. In the visual cortices of adult cats immunoreactive neurons were present throughout layers II and IV. In cerebellar cortex, Purkinje, basket, and stellate cells were immunoreactive. Comparison with staining patterns obtained with antiserum against rat parvalbumin revealed some cross-reactivity but confirmed the existence of species differences in the antigenic structure of rat and cat parvalbumin.

Amino Acids↗
PubMed1987

Developmental and functional studies of parvalbumin and calbindin D28K in hypothalamic neurons grown in serum-free medium.

The Ca2+-binding proteins parvalbumin (Mr = 12K) and calbindin D28K [previously designated vitamin D-dependent Ca2+-binding protein (Mr = 28K)] are neuronal markers, but their functional roles in mammalian brain are unknown. The expression of these two proteins was studied by immunocytochemical methods in serum-free cultures of hypothalamic cells from 16-day-old fetal mice. Parvalbumin is first detected in all immature neurons, but during differentiation, the number of parvalbumin-immunoreactive neurons greatly declines to a level reminiscent of that observed in vivo, where only a subpopulation of neurons stains for parvalbumin. In contrast, calbindin D28K was expressed throughout the period investigated only in a distinct subpopulation of neurons. Depolarization of fully differentiated hypothalamic neurons in culture resulted in a dramatic decrease of parvalbumin immunoreactivity but not of calbindin D28K immunoreactivity. The parvalbumin staining was restored on repolarization. Because the anti-parvalbumin serum seems to recognize only the metal-bound form of parvalbumin, the loss of immunoreactivity may signal a release of Ca2+ from intracellular parvalbumin during depolarization of the cells. We suggest that parvalbumin might be involved in Ca2+-dependent processes associated with neurotransmitter release.

Animals↗
PubMed2000

Purification, biochemical, and immunological characterisation of a major food allergen: different immunoglobulin E recognition of the apo- and calcium-bound forms of carp parvalbumin.

BACKGROUND: Almost 4% of the population suffer from food allergy which is an adverse reaction to food with an underlying immunological mechanism. AIMS: To characterise one of the most frequent IgE defined food allergens, fish parvalbumin. METHODS: Tissue and subcellular distribution of carp parvalbumin was analysed by immunogold electron microscopy and cell fractionation. Parvalbumin was purified to homogeneity, analysed by mass spectrometry and circular dichroism (CD) spectroscopy, and its allergenic activity was analysed by IgE binding and basophil histamine release tests. RESULTS: The isoelectric point (pI) 4.7 form of carp parvalbumin, a three EF-hand calcium-binding protein, was purified to homogeneity. CD analysis revealed a remarkable stability and refolding capacity of calcium-bound parvalbumin. This may explain why parvalbumin, despite cooking and exposure to the gastrointestinal tract, can sensitise patients. Purified parvalbumin reacted with IgE of more than 95% of individuals allergic to fish, induced dose-dependent basophil histamine release and contained, on average, 83% of the IgE epitopes present in other fish species. Calcium depletion reduced the IgE binding capacity of parvalbumin which, according to CD analysis, may be due to conformation-dependent IgE recognition. CONCLUSIONS: Purified carp parvalbumin represents an important cross reactive food allergen. It can be used for in vitro and in vivo diagnosis of fish-induced food allergy. Our finding that the apo-form of parvalbumin had a greatly reduced IgE binding capacity indicates that this form may be a candidate for safe immunotherapy of fish-related food allergy.

Allergens↗
PubMed1986

Isolation of a rat parvalbumin gene and full length cDNA.

The complete sequence of the rat parvalbumin mRNA was determined by sequencing a near full length cDNA clone and a primer extension product of the 5' untranslated region of this clone. The parvalbumin sequence contained 72 nucleotides of the 5' untranslated region, 333 nucleotides of the coding sequence, and 183 nucleotides of the 3' untranslated sequence in the case of the shorter parvalbumin messenger RNA or 556 nucleotides in the case of the larger parvalbumin messenger RNA. The two RNAs were derived from a single primary transcript since two clones were sequenced which were identical except for the site of polyadenylation. The polyadenylation signal of the shorter, more abundant RNA was AATAAA while the putative signal for the larger RNA was GATAAA. A 32-base pair sequence comprising part of the 5' untranslated region and the first seven codons of the parvalbumin cDNA was 81% homologous to a region of the chicken calmodulin cDNA encoding part of the first Ca2+-binding domain. This homology indicates that this portion of the parvalbumin mRNA may have evolved from a primordial first domain. A parvalbumin genomic clone which hybridized to probes derived from both the coding and 3' untranslated region of the cDNA was cloned from a rat genomic library. Partial sequencing identified an uninterrupted stretch of 585 base pairs identical to the 3' end of the parvalbumin cDNA. Two introns were localized in the genomic clone. Their position with respect to the parvalbumin amino acid sequence corresponded to the intron locations found in genes of several other Ca2+-binding proteins. This result indicates that, despite the deletion of one Ca2+-binding domain, the remainder of the parvalbumin gene has maintained the structural pattern of the Ca2+-binding protein gene family.

Amino Acid Sequence↗
PubMed1993

Distribution of parvalbumin-immunoreactive cells and fibers in the monkey temporal lobe: the amygdaloid complex.

The calcium-binding protein parvalbumin was immunohistochemically localized in the monkey amygdaloid complex. Parvalbumin-immunoreactive neuronal cell bodies, fibers, and terminals were observed in several amygdaloid nuclei and cortical areas. Three types of aspiny neurons, ranging from small spherical cells (Type 1) to large multipolar cells (Type 2) and fusiform cells (Type 3) were observed in most amygdaloid regions, though the proportions of the cell types were different in each region. The density of parvalbumin-immunoreactive fibers and terminals tended to parallel the density of labeled cell bodies. The highest densities of parvalbumin profiles were observed in the nucleus of the lateral olfactory tract, the periamygdaloid cortex (PAC2), the magnocellular division of the basal nucleus, the ventrolateral portion of the lateral nucleus, and the accessory basal nucleus. The regions containing the lowest densities of parvalbumin-positive profiles were the medial nucleus, anterior cortical nucleus, central nucleus, and the paralaminar nucleus. In regions with fiber and terminal labeling, pericellular networks of fibers, reminiscent of basket cell terminations, were commonly observed to surround unstained neuronal cell bodies and proximal dendrites. In the magnocellular division of the basal nucleus, and to a lesser extent in the lateral nucleus, parvalbumin-labeled "cartridges" of axo-axonic terminals were observed on the initial segments of unlabeled cells. Parvalbumin-positive varicosities were also commonly observed in close apposition to the soma and dendrites of parvalbumin-immunoreactive cells. Given the close correspondence between the distribution of parvalbumin-positive neurons and a subset of GABAergic neurons in many brain regions, these data provide a first indication of the organization of the inhibitory circuitry of the primate amygdaloid complex.

Amygdala↗