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Purification, reactivity with IgE and cDNA cloning of parvalbumin as the major allergen of mackerels.

Three species of mackerels (Scomber japonicus, S. australasicus and S. scombrus) are widely consumed and considered to be most frequently involved in incidents of IgE-mediated fish allergy in Japan. In this study, parvalbumin, a possible candidate for the major allergen, was purified from the white muscle of three species of mackerels by gel filtration on Sephadex G-75 and reverse-phase HPLC on TSKgel ODS-120T. All the purified preparations from three species gave a single band of about 11 kDa and were clearly identified as parvalbumins by analyses of their partial amino acid sequences. In ELISA experiments, four of five sera from fish-allergic patients reacted to all the purified parvalbumins, demonstrating that parvalbumin is the major allergen in common with the mackerels. Antigenic cross-reactivity among the mackerel parvalbumins was also established by ELISA inhibition experiments. A cDNA library was constructed from the white muscle of S. japonicus and the cDNA encoding parvalbumin was cloned. The amino acid sequence translated from the nucleotide sequence revealed that the S. japonicus parvalbumin is composed of 108 residues, being a member of beta-type parvalbumins.

Allergens↗

The distribution of calbindin, calretinin and parvalbumin immunoreactivity in the human thalamus.

UNLABELLED: Calcium-binding proteins show a heterogeneous distribution in the mammalian central nervous system and are useful markers for identifying neuronal populations. The distribution of the three major calcium-binding proteins - calbindin-D28k (calbindin), calretinin and parvalbumin - has been investigated in eight neurologically normal human thalami using standard immunohistochemical techniques. Most thalamic nuclei show immunoreactive cell bodies for at least two of the three calcium-binding proteins; the only nucleus showing immunoreactivity for one calcium-binding protein is the centre médian nucleus (CM) which is parvalbumin-positive. Overall, the calcium-binding proteins show a complementary staining pattern in the human thalamus. In general terms, the highest density of parvalbumin staining is in the component nuclei of the ventral nuclear group (i.e. in the ventral anterior, ventral lateral and ventral posterior nuclear complexes) and in the medial and lateral geniculate nuclear groups. Moderate densities of parvalbumin staining are also present in regions of the mediodorsal nucleus (MD). By contrast, calbindin and calretinin immunoreactivity both show a similar distribution of dense staining in the thalamus which appears to complement the pattern of intense parvalbumin staining. That is, calbindin and calretinin staining is most dense in the rostral intralaminar nuclear group and in the patchy regions of the MD which show very low levels of parvalbumin staining. However, calbindin and calretinin also show low levels of staining in the ventral nuclear complex and in the medial and lateral geniculate bodies which overlaps with the intense parvalbumin staining in these regions. These results show that the calcium-binding proteins are heterogeneously distributed in a complementary fashion within the nuclei of the human thalamus. They provide further support for the concept recently proposed by Jones (Jones, E.G., 1998. VIEWPOINT: the core and matrix of thalamic organization. Neuroscience 85, 331-345) that the primate thalamus comprises of a matrix of calbindin immunoreactive cells and a superimposed core of parvalbumin immunoreactive cells which may have differential patterns of cortical projections.

Adult↗

A method for triple fluorescence labeling with Vicia villosa agglutinin, an anti-parvalbumin antibody and an anti-G-protein-coupled receptor antibody.

The aim of the original study [S.B. Bausch, C. Chavkin, Vicia villosa agglutinin labels a subset of neurons coexpressing both the mu opioid receptor and parvalbumin in the developing rat subiculum, Dev. Brain Res., 97, 1996, 169-177] [3] was to develop a method for identifying a subset of mu opioid receptor-expressing interneurons in the rat subiculum for electrophysiological studies. Previous studies had shown that a subset of parvalbumin-positive neurons in the rat subiculum could be labeled with the lectin, Vicia villosa agglutinin (VVA) [C.T. Drake, K.A. Mulligan, T.L. Wimpey, A. Hendrickson, C. Chavkin, Characterization of Vicia villosa agglutinin-labeled GABAergic neurons in the hippocampal formation and in acutely dissociated hippocampus, Brain Res., 554, 1991, 176-185] [11], and that mu opioid receptor immunoreactivity (-IR) and parvalbumin-IR were colocalized in a subset of neurons in the hippocampus and dentate gyrus [S.B. Bausch, C. Chavkin, Colocalization of mu and delta opioid receptors with GABA, parvalbumin and a G-protein-coupled inwardly rectifying potassium channel in the rodent brain, Analgesia, 1, 1995, 282-285] [2]. We hypothesized that a subset of mu opioid receptor-expressing neurons in the subiculum also would express the calcium binding protein, parvalbumin, and could be labeled with VVA. Labeling of live neurons with VVA [11] then could be used to identify these neurons. This protocol was designed to triple-label neurons expressing the mu opioid receptor, parvalbumin and the carbohydrate group, N-acetylgalactosamine (which binds VVA [S.E. Tollefsen, R. Kornfeld, The B4 lectin from Vicia villosa seeds interacts with N-acetylgalactosamine residues alpha-linked to serine or threonine residues in cell surface glycoproteins, J. Biol. Chem., 258, 1983, 5172-5176][M.P. Woodward, W.W. Young, R.A. Bloodgood, Detection of monoclonal antibodies specific for carbohydrate epitopes using periodate oxidation, J. Immunol. Methods, 78, 1985, 143-153] [25, 29]). VVA labeling and immunocytochemistry with an affinity-purified anti-mu opioid receptor antibody [S.B. Bausch, T.A. Patterson, M.U. Ehrengruber, H.A. Lester, N. Davidson, C. Chavkin, Colocalization of mu opioid receptors with GIRK1 potassium channels in rat brain: an immunocytochemical study, Recept. Channels, 3, 1995, 221-241] [4] and an anti-parvalbumin antibody [M.R. Celio, W. Baier, L. Scharer, P.A. de Viragh, C. Gerday, Monoclonal antibodies directed against the calcium binding protein parvalbumin, Cell Calcium, 9, 1988, 81-86] [8] were used to accomplish this goal. Immunofluorescence was used as the detection method; visualization was accomplished with three fluorophores with different excitation/emission spectra and a one laser confocal microscope. This protocol can be modified easily to triple-label neurons for other carbohydrate groups and proteins.

Animals↗

Cloning of two distinct cDNAs encoding parvalbumin, the major allergen of Atlantic salmon (Salmo salar).

Allergy to fish is common in Northern Europe. Variable reactions to different fish species are usually experienced among fish allergic patients. The allergens of cod fish and particularly the major allergen parvalbumin beta (Gadus callarias) have been extensively studied in Norway. In the present communication, the white muscle parvalbumin was similarly found to be a major allergen in Atlantic salmon (Salmo salar, Sal sl). A purified salmon parvalbumin was obtained by anion exchange chromatography, gel filtration chromatography (GFC) and high-performance liquid chromatography (HPLC) of the muscle extracts. The antigenicity and allergenicity of salmon parvalbumin were confirmed using various immunologic and electrophoretic techniques. The protein is representative for several isoallergens judged by the amino acid (AA) sequence variance at certain sites in the AA sequence of CNBr cleavage peptides. Using sera from patients with cod and salmon allergy Sal sl was demonstrated to be the major allergen of Atlantic salmon, as judged by RAST- and ELISA-inhibitions and crossed radioimmunoelectrophoresis (CRIE) techniques. The protein was also demonstrated to be antigenic by the use of polyclonal cod and salmon antibodies in IgG ELISA and immunoelectrophoretic methods. Cloning of parvalbumin cDNA from Atlantic salmon was performed based on an alignment of parvalbumin AA sequences from other species. A probe was generated by PCR and used for screening a salmon muscle cDNA-library. Subcloning and sequencing of two hybridizing clones revealed transcripts from two different parvalbumin genes. The translated sequences of both clones belong to the beta-lineage of parvalbumins and include the entire coding region.

Allergens↗

Anomalous inhibitory circuits in cortical tubers of human tuberous sclerosis complex associated with refractory epilepsy: aberrant expression of parvalbumin and calbindin-D28k in dysplastic cortex.

Damage or loss of inhibitory cortical gamma-aminobutyric acid (GABA)ergic interneurons is associated with impaired inhibitory control of neocortical pyramidal cells, leading to hyperexcitability and epileptogenesis. The calcium binding proteins parvalbumin and calbindin-D(28k) are expressed in subpopulations of GABAergic local circuit neurons in the neocortex and can serve as neuronotypic markers. Parvalbumin and calbindin-D(28k) facilitate the neuron's ability to sustain firing and provide neuroprotection. The goal of this study was to assess the hitherto unknown status of inhibitory interneurons in cortical tubers of human tuberous sclerosis complex. Surgically excised cortical tubers from three patients with tuberous sclerosis complex were evaluated immunohistochemically with antibodies to parvalbumin and calbindin-D(28k). Cortical specimens from young patients with intractable seizures, including microdysgenesis (n = 3), postischemic cortical scarring (n = 1), porencephaly (n = 1), postictal gliosis (n = 3), and low-grade neuronal or glial tumors (n = 5), were also examined for comparison. In cortical tubers, calcium binding protein immunoreactivities (calbindin-D(28k) > parvalbumin) were present in medium- or large-size dysplastic neurons, whereas giant or ballooned cells were parvalbumin or calbindin-D(28k) negative. In microdysgenesis, a nearly normal number of parvalbumin-positive neurons and a decreased number of calbindin-D(28k)-positive neurons were present. In peritumoral but more so in gliotic cortex, a coordinate decrease of parvalbumin and calbindin-D(28k) immunoreactivities was present. Our findings indicate that the expression of parvalbumin or calbindin-D(28k) by subpopulations of dysplastic neurons in cortical tubers is aberrant and denotes dysfunctional inhibitory circuits inept for excitoprotection.

Adolescent↗

Parvalbumin exists in rat endocrine glands.

Simple and rapid purification procedures for parvalbumin, one of the Ca2+-binding proteins (extracted from rat skeletal muscle), were developed, and its antiserum was produced in rabbits to measure the parvalbumin content of various rat tissues by RIA. The heat treatment, ammonium sulfate fractionation, and trichloroacetic acid precipitation of soluble fraction from rat skeletal muscle followed by single diethylaminoethyl Sephadex A-50 column chromatography yielded a pure 120 mg protein from 150 g skeletal muscle. Amino acid analysis, together with electrophoretic mobility, indicated that the protein was identical to parvalbumin. The antisera to this rat skeletal muscle parvalbumin (raised in rabbits) did not cross-react with calmodulin or S-100 proteins. The RIA for parvalbumin using this antisera and [125I]parvalbumin revealed that skeletal muscle and brain contained high levels of the antigen; the values of which were 69,486 +/- 4,933.1 and 881 +/- 165.6 ng/mg protein, respectively. However, the parvalbumin antigen in the heart, lung, liver, and spleen could not be detected. On the other hand, the contents of the antigen in the endocrine glands (in nanograms per mg protein) were as follows: pituitary (125 +/- 46.6), thyroid (108 +/- 50.0), adrenal (341 +/- 64.3), testes (227 +/- 37.2), and ovaries (218 +/- 10.1). All of these values were comparable to levels of antigen found in the brain sample. These results suggest an important role for parvalbumin in endocrine glands.

Adrenal Glands↗

Effect of parvalbumin and S-100 protein on protein synthesis in rabbit reticulocyte lysate.

The effect of two high affinity Ca+ binding acidic proteins, parvalbumin and S-100 protein on protein synthesis in rabbit reticulocyte lysates (RRL), was investigated. Nuclease-treated RRL, supplemented with yeast mRNA, and 3H-leucine were incubated at 37 degrees C, and incorporation of 3H-leucine into protein was determined for 24 min. At 20 micrograms/100 microliters lysate concentration, both parvalbumin and S-100 protein caused a marked inhibition of protein synthesis compared with the control lysate. At a lower concentration parvalbumin was less inhibitory than histone H1; the effect of S-100 protein was not significant. The combined inhibitory effect of parvalbumin and H1 was not additive probably due to strong interaction between them as was evidenced by the enhanced absorbance of parvalbumin-H1 mixture. Spectrophotometric profiles of parvalbumin-tRNA mixture indicated that, unlike H1, parvalbumin did not inhibit protein synthesis by binding with nucleic acids. These results suggest an important role for parvalbumin in translational regulation.

Animals↗

Morphological and physiological properties of parvalbumin- and calretinin-containing gamma-aminobutyric acidergic neurons in the substantia nigra.

Evidence for the existence of different populations of gamma-aminobutyric acid (GABA)-ergic neurons in the substantia nigra comes partially from anatomical studies, which have shown there to be little if any overlap between the calcium-binding proteins parvalbumin and calretinin in individual neurons, suggesting that these may represent neuronal subtypes with distinct electrophysiological and/or anatomical properties. We obtained whole-cell recordings from neurons in the substantia nigra pars reticulata in rat brain slices and labeled them with biocytin, followed by immunocytochemical staining for parvalbumin and calretinin. In other cases, neurons were retrogradely labeled from the thalamus or tectum and immunocytochemically identified to determine their projection sites. Intracellularly stained neurons were found to have a variety of somatic sizes and shapes. Reconstructions revealed that all parvalbumin- and calretinin-positive neurons issued at least one axon collateral, which ramified within the substantia nigra pars reticulata and/or pars compacta. Local collaterals were of medium caliber and branched modestly, expressing many long, smooth segments that then issued numerous en passant or terminal boutons, consistent with previous in vivo studies. There were no clear differences in the electrophysiological or morphological properties of neurons expressing parvalbumin or calretinin. Retrograde tracing experiments revealed that both parvalbumin- and calretinin-containing neurons project nonpreferentially to the thalamus or tectum. In sum, the parvalbumin- and calretinin-containing GABAergic neurons of the substantia nigra pars reticulata cannot be differentiated on the basis of their electrophysiological properties, morphological properties, or target nuclei, and both parvalbumin- and calretinin-containing projection neurons issue local axon collaterals that arborize within the substantia nigra.

Animals↗

Distribution of parvalbumin-immunoreactive cells and fibers in the monkey temporal lobe: the hippocampal formation.

The distribution of parvalbumin-immunoreactive cells and fibers in the various fields of the hippocampal formation was studied in the macaque monkey. Parvalbumin-immunoreactive neurons had aspiny or sparsely spiny dendrites that often had a beaded appearance; most resembled classically identified interneurons. Parvalbumin-immunoreactive fibers and terminals were confined to certain laminae in each field and generally had a pericellular distribution. In the dentate gyrus, there was a dense pericellular plexus of immunoreactive terminals in the granule cell layer. Except for a narrow supragranular zone, there was a marked paucity of terminals in the molecular and polymorphic cell layers. Immunoreactive neurons were mainly located immediately subjacent to the granule cell layer and comprised a variety of morphological cell types. The three fields of the hippocampus proper (CA3, CA2, and CA1) demonstrated differences in their parvalbumin staining characteristics. In CA3, there was a prominent pericellular terminal plexus in the pyramidal cell layer that was densest distally (closer to CA2). Immunoreactive cells were located either in the pyramidal cell layer, where many had a pyramidal shape and prominent apical and basal dendrites, or in stratum oriens. CA2 had a staining pattern similar to that in CA3, though both the number of labeled cells and the density of the pericellular terminal plexus were greater in CA2. In CA1, there was a markedly lower number of parvalbumin-labeled cells than in CA3 and CA2 and the cells tended to be located in the deep part of the pyramidal cell layer or in stratum oriens. The pyramidal cell layer of CA1 contained a pericellular terminal plexus that was substantially less dense than in CA3 and CA2. At the border between CA1 and the subiculum there was a marked increase in the number of parvalbumin-immunoreactive neurons. The positive cells were scattered throughout the pyramidal cell layer of the subiculum and comprised a variety of sizes and shapes. Terminal labeling was higher in the pyramidal cell layer of the subiculum than in CA1. Layer II of the presubiculum had one of the highest densities of fiber and terminal labeling in the hippocampal formation. The density of staining was lower in the superficial portion of the layer where linear cartridges of presumed axo-axonic synapses were common. A large number of parvalbumin-immunoreactive cells were scattered throughout layer II of the presubiculum; small, spherical, multipolar cells were commonly observed in layer I. The parasubiculum had a somewhat lower density of positive cells and fibers than the presubiculum.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Histological identification of premotor neurons for horizontal saccades in monkey and man by parvalbumin immunostaining.

The premotor excitatory and inhibitory burst neurons are essential for horizontal saccades. In the monkey, excitatory burst neurons lie in the ipsilateral paramedian pontine reticular formation, and the inhibitory burst neurons lie more caudally in the contralateral nucleus paragigantocellularis dorsalis. For a neuropathological analysis of degenerative changes in saccadic disorders of patients, the histological identification of the burst neuron areas in man is important. Here, we show that this is possible with parvalbumin immunostaining as a histological marker. First, in monkeys, the premotor burst neurons were backlabeled by injections of wheat germ agglutinin-horseradish peroxidase or cholera toxin subunit B into the abducens nucleus or tetanus toxin fragment C into the lateral rectus muscle and shown by double labeling to contain parvalbumin. Then, human brainstem sections were immunoreacted for parvalbumin, and, by comparing the resulting staining pattern to that in the monkey, the homologous burst neuron areas were defined in man. In the monkey, excitatory burst neurons were confirmed to the nucleus reticularis pontis caudalis and did not extend farther rostrally into the nucleus reticularis pontis oralis. All retrogradely labeled cells in both burst neuron areas were parvalbumin positive, and approximately 70% of the parvalbumin-positive cells were retrogradely labeled. Both burst neuron areas were highlighted by their parvalbumin staining pattern and could be outlined in man as well. The putative excitatory burst neuron area in man is in the medial part of the nucleus reticularis pontis caudalis (extending 2.5 mm mediolaterally), immediately rostral (250 microns) to the omnipause neurons and extending 2.2 mm rostrally, and the putative inhibitory burst neuron area lies in the medial part of the paragigantocellular nucleus caudal to the abducens nucleus, extending 1.8 mm caudally. The location of the burst neuron areas, including the burst neurons themselves, via parvalbumin immunostaining will help in the analysis of clinical cases with slow saccades.

Animals↗

Prenatal exposure to cocaine selectively disrupts the development of parvalbumin containing local circuit neurons in the medial prefrontal cortex of the rat.

Exposure to cocaine in utero can result in cognitive deficits potentially through a disruption in the inhibitory processes of the frontal cortex. One potential mechanism is through alterations in the inhibitory local circuit neurons containing the calcium-binding protein, parvalbumin. Parvalbumin-immunostaining primarily identifies 2 types of local circuit neurons: larger, rounder, axo-somal basket cells and smaller, more-spindle shaped, axo-axonic chandelier cells. Both are thought to have critical impact on the excitatory/inhibitory balance due to the proximal site of projection on pyramidal neurons. Calretinin, another calcium-binding protein, identifies a distinct sub-population of inhibitory local circuits that impinges more distally on the dendritic arbor and serves as a control population for this study. Here, we examine local circuit neurons containing either parvalbumin or calretinin in adolescent male rats (approximately 45 days old) exposed to saline or cocaine (3 mg/kg, intravenous twice a day during embryonic days 10 to 20). Prenatal cocaine exposure caused select changes in the parvalbumin, but not calretinin, containing cells in the frontal cortex. Specifically, prenatal cocaine exposure is associated with a 50% reduction in spindle-shaped parvalbumin-immunoreactive cells potentially indicating a select loss of chandelier cells or a shift to a rounder shape. Additionally, a reduction in the number of dendrites of parvalbumin-immunoreactive cells in rats exposed to cocaine in utero was noted. Other measures of both parvalbumin- and calretinin-immunoreactive cells were unchanged, including total number of cells, distribution by depth, and sizes of cells. These changes to the excitatory/inhibitory balance in the frontal cortex may contribute to the cognitive deficits associated with prenatal cocaine exposure.

Animals↗

Postnatal development of parvalbumin immunoreactivity in striated muscles of the rat.

The presence of parvalbumin, a calcium-binding protein, has been correlated with the maturation of locomotor activity in developing striated muscle. In the present study, postnatal parvalbumin immunoreactivity is examined in the tibialis anterior, intercostal, diaphragm and intrinsic muscles of the tongue of the rat to gather a better understanding of the different developmental patterns. Parvalbumin immunoreactivity appears in the anterior tibialis muscle by day 4, and reaches an adult checkerboard pattern 2 days later. In contrast, parvalbumin immunoreactivity in the intrinsic muscles of the tongue, and in diaphragm and intercostal muscles, which are active near birth, does not appear until the 2nd week. Therefore, these features suggest that parvalbumin immunoreaction is not exclusively dependent on functional activity. In addition, the finding that differences in parvalbumin expression do not correlate in time with the differentiation of fiber types as judged by myosin ATPase activity, suggests that myosin and parvalbumin might be regulated by different mechanisms.

Adenosine Triphosphatases↗

Parvalbumins and muscle relaxation: a computer simulation study.

The distribution of Ca2+ and Mg2+ among the 'regulatory' cation binding sites of troponin (T-sites) and the strong, Ca2+-Mg2+ binding sites of troponin and parvalbumins (P-sites) in the sarcoplasm of a muscle was calculated. At rest, 60% of the T-sites were metal free, while 92% of the P-sites were loaded with Mg2+. In response to a Ca2+ pulse, troponin-calcium (T-Ca) complexes were rapidly formed, while the binding of Ca2+ to P-sites was limited by the slow rate of dissociation of the parvalbumin-magnesium (P-Mg) complexes. Muscle activation was not prevented by a high content of parvalbumins. Parvalbumin and the sarcoplasmic reticulum (SR) pump were complementary relaxing factors that removed Ca2+ from the cytosol and from the T-sites. Parvalbumins dominated the first part of relaxation, while the action of the SR was essential to ensure the return to a very low level of free Ca2+ ion and of T-Ca. After relaxation, a large fraction of the Ca2+ pulse was still bound to parvalbumins and returned slowly to the SR during the recovery. When the SR activity was reduced, the presence of parvalbumins preserved a fast rate of relaxation, at least for a few contractions. This may have a high adaptive value in cold-blooded animals.

Amphibians↗

Immunohistochemical localization of parvalbumin in rat and monkey autonomic ganglia.

The cellular distribution of parvalbumin-like immunoreactivity in autonomic ganglia such as superior cervical sympathetic ganglia, paravertebral sympathetic chain ganglia (T6), ciliary ganglia and enteric ganglia was investigated by immunohistochemical peroxidase-antiperoxidase methods using an antiserum against rat skeletal muscle parvalbumin. We detected parvalbumin-like immunoreactivity in almost all neurons of rat superior cervical sympathetic ganglia and other paravertebral sympathetic chain ganglia, where the antigen was located in the cytoplasm but the nuclei were not labelled. No neurons positive for parvalbumin-like immunoreactivity were observed in rat ciliary ganglia or enteric ganglia. In monkey, almost all neurons of the superior cervical sympathetic ganglia contained parvalbumin-like immunoreactivity, but none of the neurons of the ciliary ganglia were labelled with the antiserum to parvalbumin. These results suggest that parvalbumin-like immunoreactivity exists in a specific subpopulation of the neurons of the autonomic nervous system.

Animals↗

Parvalbumin-containing cells of the angular portion of the vertical limb terminate on calbindin-immunoreactive neurons located at the border between the lateral and medial septum of the rat.

In the septal complex, both parvalbumin and calbindin neurons cocontain GABA. In the same area, a large number of GABA-GABA synaptic connections can be observed. In order to further characterize their neurochemical nature, as well as the extrinsic and/or intrinsic origin of these GABA terminals, the following experiments were performed: (1) correlated light- and electron-microscopic double immunostaining for calbindin and parvalbumin on septal sections of control rats: (2) light microscopic parvalbumin immunostaining of septal sections after surgical isolation (5 days) of the septum from its telencephalic or (3) hypothalamic afferents; and (4) parvalbumin immunostaining of sections prepared from the entire brain 2 days following horseradish peroxidase injection into the border between the lateral and medial septum. The results demonstrated that: (1) in a well-circumscribed, vertically longitudinal area located between the lateral and medial septum, 0.1-0.6 mm anterior to the bregma, a group of calbindin-containing, nonsomatospiny neurons are surrounded by parvalbumin-immunoreactive baskets; (2) these basket-forming axon terminals establish symmetric synaptic contacts with their targets; and (3) their cells of origin are not in the medial septum, but in the angular portion of the vertical limb. These observations indicate that a portion of the septal complex GABA-GABA synaptic connections represent functional interaction between two different types of GABAergic neurons. The presynaptic GABAergic neurons contain parvalbumin, and the postsynaptic GABAergic cells are immunoreactive for calbindin. Furthermore, a population of the medial septum/diagonal band parvalbumin neurons project only to the hippocampus, while others, which may also send axons to the hippocampus, terminate on lateral septum calbindin cells as well.

Animals↗

The development of parvalbumin and calbindin-D28k immunoreactive interneurons in kitten visual cortical areas.

Calbindin-D and parvalbumin are calcium binding proteins which are found in non-overlapping subpopulations of GABA-ergic interneurons in mammalian neocortex. We studied the development of these calcium-binding proteins in interneurons of cat striate and extrastriate cortical areas which have differing patterns of connectivity and follow different developmental timetables. We examined primary visual areas 17 and 18, secondary visual area 19, medial lateral suprasylvian and lateral suprasylvian areas (MLS and LLS) and association areas 7 and the splenial visual area from the day of birth (P0) through P101. Parvalbumin-immunoreactive (ir) interneurons followed the inside-out pattern of maturation of cortical laminae. They were located only in infragranular layers at the earliest ages and were not observed in the overlying cortical plate. At 3 weeks of age, when cortical lamination is mature, parvalbumin stained cells were found in all cortical layers except layer I. The number of stained secondary and tertiary dendrites in the parvalbumin-ir interneuronal population decreased with age. This change was associated with a shift in the molecular weight of parvalbumin detected on Western blots. During the first postnatal week, the area 17/18 border contained more parvalbumin-ir neurons than other visual areas. The developmental pattern of calbindin staining differed considerably from the parvalbumin staining pattern. Very few calbindin-ir interneurons were seen in area 17 during the first 2 weeks of life. In lateral cortical areas, calbindin-ir neurons were located in cortical plate, infragranular layers of cortex and white matter/subplate. Calbindin-ir neurons increased in supragranular layers of secondary cortical areas by P7 and in area 17 by P20. In the mature cortex, the calbindin staining pattern was bilaminar, with a dense band of calbindin-ir cells in layer II and a second band in layers V-VI. There was no difference in the distribution of calbindin-ir neurons among visual areas at maturity.

Animals↗

Parvalbumin immunoreactivity in the hippocampus of the gerbil after transient forebrain ischaemia: a qualitative and quantitative sequential study.

Parvalbumin immunoreactivity is examined in the hippocampus of the Mongolian gerbil (Meriones unguiculatus) in controls and in animals subjected to 20 min of forebrain ischaemia produced by bilateral clipping of the carotids. In comparison with other species, the hippocampus of the gerbil is characterized by strong immunoreactivity of the (presumably excitatory) perforant pathway, and weak immunoreactivity (low numbers of neurons and scarce dendritic arbors) in nonpyramidal nerve cells (inhibitory neurons) of the CA1 area. These properties may play some role in the development and maintenance of seizures in this susceptible species. Parvalbumin immunoreactivity is rapidly and ephemerally increased in the hippocampus 15 min after reperfusion. Later on, there is a transitory decrease of parvalbumin immunoreactivity which is followed by an increase 6 h later in the stratum granulare hilus and CA3 area, and not until the first and second days in the CA1 area. This increase significantly surpasses the number of immunoreactive neurons in control animals in CA1 and CA3 from 48 h after reperfusion onwards. The effect is similar using different anaesthetics and does not occur in sham-operated animals. In contrast with these findings, the number of parvalbumin-immunoreactive neurons in the somatosensory cortex is not affected in our model of forebrain ischaemia. On the other hand, GABA-immunoreactive neurons in CA1 are preserved during the first week after reperfusion, although an increase in the number of these cells occurs at the end of this period. Delayed neuronal death occurs in the CA1 area 48 h after ischaemia, and marked reduction in the number of CA1 neurons is found by the end of the first week. Eighty per cent of the remaining cells in CA1 at day 7, and 83% at day 15, are parvalbumin-immunoreactive nonpyramidal neurons in contrast to 3% parvalbumin-immunoreactive cells in control animals. These findings indicate that GABAergic neurons in CA1 are preserved after forebrain ischaemia, and that parvalbumin in CA1 neurons is associated with survival.

Animals↗

Parvalbumin and calbindin in the rat claustrum: an immunocytochemical study combined with retrograde tracing frontoparietal cortex.

The distribution of the calcium binding proteins parvalbumin and calbindin D-28k was examined in the claustrum of the rat by means of immunohistochemistry. The two proteins displayed a different and largely complementary pattern of distribution. Parvalbumin-immunostaining was intense in the neuropil of the dorsal claustrum and virtually absent in the neuropil of the ventral claustrum; parvalbumin-immunoreactive neuronal cell bodies were relatively numerous in the dorsal claustrum and were detected only occasionally in the ventral region. On the other hand, calbindin-immunostaining was prevalent in the ventral claustrum; very few calbindin-positive neurons were seen in the dorsal sector of the nucleus, whereas they were relatively more numerous in the ventral claustrum. The cell bodies of the majority of the claustral parvalbumin- or calbindin-immunoreactive neurons were oval or round, but immunostained polymorphous neurons were also observed. The surface of the immunopositive dendritic branches was smooth, with no evidence of spines. Fluorescent retrograde tracing was combined with immunohistofluorescence to determine whether the parvalbumin-containing claustral cells project to the frontoparietal cortex. Neurons labelled after large fluorogold injections in frontoparietal cortical fields were highly intermingled in the dorsal claustrum with parvalbumin-immunoreactive cells but the two neuronal populations were separate. These data show that parvalbumin-immunoreactive claustral neurons do not project to the frontoparietal cortex. In addition, although these cells may project to other cortical or subcortical targets, the present findings suggest that they may represent, at least in part, local circuit claustral neurons, corresponding to the aspiny intrinsic neurons described in the rat claustrum in studies based on Golgi impregnation.

Animals↗