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PubMed1996

Altered neuronal distribution of parvalbumin in anterior cingulate cortex of rabbits exposed in utero to cocaine.

Previous studies of rabbits exposed in utero to cocaine have revealed an increase in the number of neurons which are GABA immunoreactive in the anterior cingulate cortex (ACC), suggesting a cocaine-elicited modification in the balance of excitatory and inhibitory interactions. Of the major calcium binding proteins expressed by different subgroups of GABAergic neurons, parvalbumin has been observed in conditions involving excess excitation, and may serve to protect neurons from excitotoxicity. In the present study, we used immunocytochemistry to compare the effects of prenatal cocaine exposure on the postnatal development of parvalbumin immunoreactivity in interneurons of the visual cortex (VC) and ACC. We determined the number and laminar distribution of parvalbumin immunoreactive neurons, and we also assessed the distribution of parvalbumin immunoreactivity within primary, secondary and tertiary dendrites of neurons in these two cortical areas. In both ACC and VC, parvalbumin immunoreactive neurons were first observed around postnatal day 10 (P10) and their number increased rapidly from P10 to P20. At all ages studied (P10 to P60) there was no difference between cocaine-exposed and saline control animals in the number or laminar distribution of parvalbumin immunoreactive neurons in either cortical area. However, the distribution of parvalbumin immunoreactivity within dendrites revealed a significant difference between cocaine-exposed and saline control animals in ACC but not in VC. In ACC, at all ages studied, there was an increase in the number of primary, secondary and tertiary dendrites which were parvalbumin immunoreactive in cocaine-exposed animals compared with saline controls. This difference was most striking in secondary dendrites, and in laminae V and VI. The effect was observed at doses of 4 and 3 mg/kg per injection but not at 2 mg/kg per injection. In contrast to ACC, in VC there was no difference in the number of immunoreactive dendrites in cocaine-exposed animals compared with saline controls. These observations are consistent with the hypothesis that the ACC of rabbits exposed in utero to cocaine is characterized by altered excitatory/inhibitory interactions. ACC receives a dense dopaminergic input, but VC receives minimal dopaminergic innervation. Mechanisms by which the action of cocaine on the developing dopaminergic system may modify the balance of excitation and inhibition in ACC are discussed.

Animals↗
PubMed1993

Developmental pattern and subcellular localization of parvalbumin in the rat tooth germ.

The EF-hand calcium-binding protein parvalbumin has been extensively studied in nerve and muscle cells. Its possible role in biomineralization during tooth development was here investigated by determining its subcellular localization by immunogold cytochemistry. The developmental sequences of amelogenesis and dentinogenesis were studied in rat molars, and in continuously growing rat incisors. The findings confirm that parvalbumin is a nuclear and a cytosolic protein, not associated with any particular intracellular organelle. Epithelial and mesenchymal undifferentiated cells contained no specific parvalbumin immunolabelling. In differentiated ameloblasts, secretory-pole (Tomes' process) formation was associated with a proximal-distal gradient of parvalbumin labelling. But after the Tomes' process had formed, parvalbumin was evenly distributed throughout the cell. The parvalbumin contents of ruffle-ended and smooth-ended ameloblasts appeared to be very different. Differentiated odontoblasts were less heavily labelled than ameloblasts, and the label was restricted to the cell body during the whole of dentinogenesis. These data suggest that parvalbumin could contribute to membrane plasticity during differentiation, as shown during dendritic growth in the nervous cells. Moreover, as may occur in excitable cells, parvalbumin could buffer calcium specifically in the cells producing mineralized enamel and dentine during the later stages of tooth development.

Ameloblasts↗
PubMed1988

Postnatal development of parvalbumin-, calbindin- and adult GABA-immunoreactivity in two visual nuclei of zebra finches.

The characterization of neuron populations by their immunoreactivity against parvalbumin- and calbindin (28-kDa)-antisera has been used to study the postnatal development of the visual diencephalic nucleus rotundus and the mesencephalic nucleus isthmi complex in zebra finches. In nucleus rotundus, parvalbumin-immunoreactivity was restricted to the neuropil during the first 10 days and appears additionally in somata around day 12 where it remains until adulthood. Calbindin-immunoreactivity of the very scarce neuropil and the few somata, which can be observed during the first two weeks, disappears until adulthood. Thus, the adult nucleus rotundus shows an almost complementary distribution of calbindin- and parvalbumin-immunoreactive structures: the numerous, heavily parvalbumin-positive somata, which are surrounded by dense immunoreactive neuropil are in sharp contrast to the complete absence of calbindin-immunoreactive somata. Only a thin rim surrounding this nucleus contains punctate calbindin-positive neuropil. In the nucleus isthmi complex, parvalbumin and calbindin staining patterns show markedly different developmental profiles. While the density of parvalbumin-immunoreactive neuropil in the parvocellular part of the nucleus isthmi continuously increases and the somata remain unstained, the initially heavily calbindin-positive somata gradually lose their immunoreactivity during the first two weeks. In the adult nucleus isthmi complex, parvalbumin- and calbindin show nearly identical staining patterns. A comparison between the two calcium-binding proteins and GABA-immunoreactivity in adult brains revealed different relationships in the two nuclei: while in nucleus rotundus GABA-staining pattern neither resembles that of parvalbumin nor of calbindin, in the nucleus isthmi complex all three staining patterns coincide.

Animals↗
PubMed1991

Parvalbumin in the monkey striate cortex: a quantitative immunoelectron-microscopy study.

Parvalbumin (PV) is present in a subpopulation of interneurons in the visual cortex, and also in thalamic afferents to the neocortex of primates. The object of this study is to confirm by immunoelectron-microscopy the presence of intrinsic and extrinsic connections containing parvalbumin in the monkey visual cortex, by the demonstration of parvalbumin-immunoreactivity in symmetric and asymmetric synapses. We analyzed the distribution of parvalbumin-immunoreactive profiles at the ultrastructural level in the primary visual cortex of old world monkeys (Macaca fascicularis). It has been shown by others that parvalbumin-immunoreactive cells resemble non-spiny stellate cells, double-bouquet cells, chandelier and basket cells. These neurons are known to be inhibitory and to form symmetric synapses. In fact, we observed that the vast majority of parvalbumin-immunoreactive synaptic contacts in the primary visual cortex of Macaca fascicularis are of the symmetric type (81.7%). Since parvalbumin-positive asymmetric contacts are also present (18.3%) and occur mostly in the thalamic recipient layers, 4C and 4A (9.9%), these afferents probably derive from parvalbumin-immunoreactive neurons located in the dorsal lateral geniculate nucleus of the thalamus.

Animals↗
PubMed1992

Cortical input to parvalbumin-immunoreactive neurones in the putamen of the squirrel monkey.

The cortex projects heavily to the striatum and makes asymmetrical synaptic contact mainly with the spines of medium-sized densely spiny neurones. The possibility exists that corticostriatal terminals also make synaptic contact with classes of striatal interneurones. The primary objective of the present experiment was to determine whether parvalbumin-immunoreactive neurones, which represent a class of GABAergic interneurones in the striatum, also receive a direct synaptic input from corticostriatal fibres. The anterograde tracer biocytin was injected into the motor and premotor cortices of the squirrel monkey (Saimiri sciureus). Following perfuse-fixation, sections of the striatum were processed histochemically to reveal the transported biocytin using an avidin-biotin-peroxidase complex and diaminobenzidine as the chromogen. They were then immunostained to reveal parvalbumin using benzidine dihydrochloride as the chromogen. In both the light and electron microscopes, the morphological features and the afferent synaptic input of the parvalbumin-immunoreactive neurones were similar to those observed in other species. Similarly, the morphology and postsynaptic targets of the corticostriatal terminals were similar to those described in other species. Light microscopic examination revealed that the anterogradely labelled corticostriatal terminals were often in close apposition to the parvalbumin-positive neurones. At the electron microscopic level the biocytin-positive corticostriatal terminals were found to make asymmetrical synaptic contacts mainly with spines. The parvalbumin-positive neurones were seen to have an invaginated nucleus, extensive cytoplasm and relatively few spines. Parvalbumin-immunoreactive dendrites received a dense synaptic input consisting mainly of asymmetric synapses and only a few symmetric synapses. Biocytin-labelled corticostriatal terminals were often seen in asymmetrical synaptic contact with parvalbumin-immunoreactive dendrites. These results show that GABAergic interneurones identified on the basis of parvalbumin immunoreactivity, in addition to the projection neurones of the striatum, are under the direct influence of the cerebral cortex.

Animals↗
PubMed1994

Effects of chronic monocular enucleation on calcium binding proteins calbindin-D28k and parvalbumin in the lateral geniculate nucleus of adult rhesus monkeys.

The calcium binding proteins parvalbumin and calbindin-D28k were localized immunocytochemically within the lateral geniculate nucleus of adult monkeys at 1-7 months after monocular enucleation. Within the deafferented magno- and parvocellular layers, parvalbumin and calbindin-D28k immunoreactive fibers were depleted at all post-enucleation times. The neuronal staining for parvalbumin was similar in numerical density and intensity between the deafferented and intact layers. In hemispheres examined at 5 and 7 months post-enucleation, parvalbumin-immunoreactive fibers were also lost within the deprived ocular dominance bands in layers IVA, IVC and VI of the visual cortex, suggesting that cellular expression or axonal transport of parvalbumin may be decreased in the deafferented geniculate laminae. While the intact magno- and parvocellular layers contained very few neurons that were immunoreactive for calbindin-D28k, the density of calbindin-D28k-positive neurons increased in these layers after deafferentation. The counts of calbindin-D28k and parvalbumin immunostained neurons were not statistically different at 4-7 months post-enucleation. Because virtually all magno- and parvocellular projection neurons express parvalbumin, many parvalbumin neurons that normally do not contain calbindin-D28k may co-express this in response to injury. The findings suggest that long-term deafferentation imposes additional calcium buffering requirements on lateral geniculate neurons.

Animals↗
PubMed1995

Brainstem motoneuron pools that are selectively resistant in amyotrophic lateral sclerosis are preferentially enriched in parvalbumin: evidence from monkey brainstem for a calcium-mediated mechanism in sporadic ALS.

Some brainstem motoneuron groups appear more resistant to the process of neurodegeneration in ALS (for example, oculomotor, trochlear, and abducens nuclei) than others (for example, trigeminal, facial, ambiguus, and hypoglossal nuclei). The possibility that the differential presence of the calcium-chelating protein parvalbumin might underlie this difference in vulnerability was examined immunohistochemically as a way to determine whether a calcium-mediated mechanism might be involved in ALS. In normal monkey brainstem, we found that the abundance of parvalbumin-containing neurons in the oculomotor, trochlear, and abducens nuclei was approximately 90% of the abundance of choline acetyltransferase (CHAT)-containing motoneurons. In contrast, the abundance of parvalbumin-containing neurons in the other brainstem motor nuclei innervating skeletal muscle (trigeminal, facial, ambiguus, and hypoglossal) was only about 30-60% of the abundance of CHAT-containing motoneurons. Since some of these motoneuron pools contain nonmotoneuron internuclear neurons that might be parvalbumin-containing, we also carried out double-label studies to specifically determine the percentage of cholinergic motoneurons that contained parvalbumin in each of these motoneuron pools. We found that 85-100% of the oculomotor, trochlear, and abducens motoneurons were parvalbumin-containing. In contrast, only 20-30% of the trigeminal, facial, ambiguus, and hypoglossal motoneurons were parvalbumin-containing. These results raise the possibility that motoneuron death in sporadic ALS is related to some defect that promotes cytosolic calcium accumulation in motoneurons. This excess calcium entry may promote cell death via an excitotoxic pathway. Motoneurons rich in parvalbumin may resist the deleterious effects of this putative calcium gating defect because they are better able to sequester the excess calcium.

Amyotrophic Lateral Sclerosis↗
PubMed1988

Two-dimensional 1H nuclear magnetic resonance study of pike pI 5.0 parvalbumin (Esox lucius). Sequential resonance assignments and folding of the polypeptide chain.

The structure of alpha pike 5.0 parvalbumin under its Ca-loaded form (or PaCa2) is studied in solution by two-dimensional 1H nuclear magnetic resonance (n.m.r.) at 360 MHz using a conventional strategy of sequential assignments, which involved correlated spectroscopy, relayed coherence transfer spectroscopy and nuclear Overhauser enhancement spectroscopy. In order to overcome the problem of spectral overlapping due to the presence of 108 residues in the protein, experiments were performed at different pH and temperature values, either in 1H2O or in 2H2O solutions. The amino acid sequence of pike 5.0 parvalbumin is thus fully characterized by nearly the totality of its NH, C alpha H and C beta H resonances originating from the different residues (421 protons assigned among 429 in total). When associated with the remaining side resonances, these sequence-specific assignments provide a basis for establishing the secondary organization and tertiary folding of the polypeptide chain. Pike 5.0 parvalbumin was selected as a characteristic representative of the alpha phylogenic series, for which no crystalline structure is presently available, in contrast with the beta series for which two crystalline structures have been determined. A parvalbumin molecule with a single polypeptide chain of 108 amino acids represents one of the highest molecular weights analyzed so far by two-dimensional n.m.r. spectroscopy. The use of a moderate magnetic field strength, with 1H nuclei resonating at 360 MHz, is justified by the fact that ring current effects are operating favorably in this globular protein with a high phenylalanine content. A three-dimensional structure has been generated by the "distance geometry" or DISGEO computational procedure on the basis of about 450 interproton nuclear Overhauser enhancement connectives (short, medium and long-range) in conjunction with a selection of phi and chi dihedral angle constraints. The coherence of the calculated structure, which displays all the features of the typical folding of a parvalbumin protein, provides a good test of reliability of the n.m.r. data collected so far. Although similar to a beta parvalbumin in the folding of its polypeptide chain, the alpha parvalbumin studied here differs markedly from a beta parvalbumin in the length of its C-terminal F-helix domain, which includes 11 residues instead of ten in the latter.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1994

The development of parvalbumin-immunoreactivity in the neocortex of the mouse.

In the present study the postnatal development of parvalbumin-immunoreactivity was examined in the neocortex of the mouse. Postnatal mice were processed at different developmental stages using a well-characterized monoclonal antibody against parvalbumin, and immunocytochemistry. The first immunoreactive neurons appeared in the first parietal and retrosplenial cortices at postnatal day 10 (P10). From P11 to P12, immunoreactivity emerged in the second parietal, cingular, frontal, hindlimb-forelimb, first temporal, primary and secondary occipital and gustatory cortices, and at P14, parvalbumin-positive cells were present in the remaining regions. In general, parvalbumin-immunoreactivity appeared first in the primary sensory/motor areas, and then in second sensory/motor or associative areas. The maturation of parvalbumin-immunoreactivity, however, was a long-lasting process, which was not completed until adult stages. In all cortical regions, parvalbumin-immunoreactive cells were present first in layer V, from which immunoreactivity expanded to the upper and inner cortical layers at subsequent developmental stages. This pattern of maturation differed from the usual 'inside-out' gradient of neocortical neurogenesis and maturation. At the cellular level, parvalbumin-immunoreactivity appeared first in cell somata, and staining of dendrites and boutons was apparent two days later. From the second postnatal week onwards, an immunoreactive axonal system was observed in the neocortical white matter and the corpus callosum. We conclude that the emergence and maturation of parvalbumin-immunoreactivity in the mouse neocortex shows marked area-specific differences, but proceeds following a similar center-to-outside radial gradient. These features may reflect the acquisition of certain physiological properties by a subset of GABAergic inhibitory neurons.

Animals↗
PubMed1991

Sensitive immunoassay for rat parvalbumin: tissue distribution and developmental changes.

A sensitive enzyme immunoassay for measurements of rat parvalbumin was established using antibodies raised in rabbits with parvalbumin purified from skeletal muscles. Antibodies in the antiserum were purified with a parvalbumin-coupled Sepharose column. The sandwich-type immunoassay system for parvalbumin was composed of polystyrene balls with immobilized purified antibodies and the same antibodies labeled with beta-D-galactosidase from Escherichia coli. The assay was highly sensitive and the minimum detection limit was 1 pg parvalbumin/tube. The assay did not cross-react with other calcium binding proteins, including human S-100a0 and S-100b proteins, rat 28-kDa calbindin-D, and bovine calmodulin. High concentrations of parvalbumin were observed in the skeletal muscles, especially in those composed of fast-twitch fibers, and in the diaphragm and tongue, but not in heart muscle. A relatively high concentration was estimated in the central nervous tissue. Parvalbumin was detected in the cerebral cortex and cerebellum of gestational 15-day fetuses. However, the levels of parvalbumin in the muscle tissues and central nervous tissue were very low in rats before 1 week of age. Thereafter, they increased sharply, reaching the adult levels by 5 weeks in most of the tissues. Parvalbumin concentrations in adult rat soleus muscle increased less than 20-fold within 10 days after transection of the ipsilateral sciatic nerve, while the concentrations in the extensor digitorum longus muscle did not change in the same period.

Animals↗
PubMed1989

Analysis of parvalbumin and calbindin D28k-immunoreactive neurons in dorsal root ganglia of rat in relation to their cytochrome oxidase and carbonic anhydrase content.

Histochemical and immunohistochemical techniques were used to determine relationships between the parvalbumin or calbindin D28k content and the cytochrome oxidase or carbonic anhydrase activity of neurons in lumbar dorsal root ganglia in rat. Subpopulations of dorsal root ganglion neurons that displayed parvalbumin- or calbindin D28k-immunoreactivity were classified as containing either light, moderate or dense histochemical reaction product for cytochrome oxidase and either a positive or negative reaction for carbonic anhydrase. It was found that approximately 90% of all parvalbumin and calbindin D28k-immunoreactive cells exhibited dense staining for cytochrome oxidase and that 87% of parvalbumin- and 76% of calbindin D28k-immunoreactive cells were positive for carbonic anhydrase. Conversely, 85% of all cells with a dense cytochrome oxidase reaction contained parvalbumin and calbindin D28k. Although not quantified, it appeared that many, but not all, carbonic anhydrase-positive cells contained parvalbumin or calbindin D28k. These results indicate the existence of a subpopulation of primary sensory neurons that contains parvalbumin and calbindin D28k and that expresses high levels of cytochrome oxidase and carbonic anhydrase activity. It is suggested that primary afferent neurons with this cytochemical profile transmit a sensory modality that requires them to discharge rapidly and/or frequently. The existence of a subpopulation of carbonic anhydrase-positive cells that lack immunoreactivity for parvalbumin or calbindin D28k suggests that the role of carbonic anhydrase in some sensory neurons is unrelated to functions requiring these calcium binding proteins.

Animals↗
PubMed1990

Calbindin D-28k and parvalbumin in the rat nervous system.

This paper describes the distribution of structures stained with mono- and polyclonal antibodies to the calcium-binding proteins calbindin D-28k and parvalbumin in the nervous system of adult rats. As a general characterization it can be stated that calbindin antibodies mainly label cells with thin, unmyelinated axons projecting in a diffuse manner. On the other hand, parvalbumin mostly occurs in cells with thick, myelinated axons and restricted, focused projection fields. The distinctive staining with antibodies against these two proteins can be observed throughout the nervous system. Calbindin D-28k is primarily associated with long-axon neurons (Golgi type I cells) exemplified by thalamic projection neurons, strionigral neurons, nucleus basalis Meynert neurons, cerebellar Purkinje cells, large spinal-, retinal-, cochlear- and vestibular ganglion cells. Calbindin D-28k occurs in all major pathways of the limbic system with the exception of the fornix. Calbindin D-28k is, however, also found in some short-axon cells (Golgi type II), represented by spinal cord interneurons in layer II and interneurons of the cerebral cortex. It is also detectable in some ependymal cells and abundantly occurs in vegetative centres of the hypothalamus. The "paracrine core" of the nervous system and its adjunct (1985, Nieuwenhuys, Chemoarchitecture of the Brain. Springer, Berlin) is very rich in calbindin D-28k. The distribution of calbindin D-28k-positive neurons is very similar to that of the dihydroperydine subtype of calcium channels. Most of the cells containing calbindin D-28k are vulnerable to neurodegenerative processes. Parvalbumin-immunoreactive neurons have a different, and mostly complementary distribution compared with those which react with calbindin D-28k antisera, but in a few cases (Purkinje cells of the cerebellum, spinal ganglion neurons), both calcium-binding proteins co-exist in the same neuron. Many parvalbumin-immunoreactive cells in the central nervous system are interneurons (Golgi type II) and, to a lesser extent, long-axon cells (Golgi type I), whereas conditions are vice versa in the peripheral nervous system. Intrinsic parvalbuminic neurons are prominent in the cerebral cortex, hippocampus, cerebellar cortex and spinal cord. Long-axon parvalbumin-immunoreactive neurons are, for example, the Purkinje cells, neurons of the thalamic reticular nucleus, globus pallidus, substantia nigra (pars reticulata) and a subpopulation among large spinal-, retinal-, cochlear- and vestibular ganglion cells. Parvalbumin is rich in cranial nerve nuclei related to eye movements. In addition to nervous elements, parvalbumin immunoreactivity occurs in a few ependymal cells and in some pillar cells of the organ of Corti.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Chandelier cell axons identified by parvalbumin-immunoreactivity in the normal human temporal cortex and in Alzheimer's disease.

Parvalbumin is a calcium-binding protein which is thought to play a role in neuronal excitability. In the cerebral cortex parvalbumin is largely found in two subsets of GABAergic neurons, the chandelier and basket cells. A distinguishing characteristic of the chandelier cell is that the terminal portions of its axon form short vertical strings of boutons resembling candlesticks, which embrace the initial segment of pyramidal cell axon. In the present study, the terminals of chandelier cells in the human temporal cortex were immunostained with an antibody against parvalbumin. These terminals were found more abundantly in layers II and VI, less frequently in layers III and V, were hardly identified in layer IV, and absent in layer I. The relationship of parvalbumin-immunoreactive terminals and axon initial segments was further evidenced by re-sectioning identified rows of boutons into semithin sections. Electron microscopy of both temporal cortex and the somatosensory region of a biopsy sample revealed that these parvalbumin-positive boutons indeed form symmetric synaptic contacts on the axon initial segments of pyramidal cells. As part of an enquiry into the possibility that these specialized interneurons may be involved in degenerative neurological diseases, the temporal lobes from seven patients with Alzheimer's disease were immunostained for parvalbumin. As in the control brains, the specific terminal portions of chandelier cells were recognized and identified in the temporal cortex by parvalbumin-immunocytochemistry. No major difference from normal brains was found, excepting for a lower density of candlesticks (30-35%) in layer II-III. Since we showed in a previous study [Ferrer et al. (1991) J. neurol. Sci. 106, 135-141] that the number of parvalbumin-immunoreactive somata in the same Alzheimer's disease cases was not decreased, the observed reduction of terminals in layer II suggest that only the terminals of chandelier cells, but not the parent neurons, are decreased in Alzheimer's disease.

Aged↗
PubMed1996

Ultrastructural localization of alpha-parvalbumin in the epiphyseal plate cartilage and bone of growing rats.

The distribution of the calcium-binding protein, alpha-parvalbumin, in the epiphyseal plate cartilage and bone of growing rats was examined by electron microscope immunocytochemistry of undecalcified samples. Parvalbumin immunoreactivity, as revealed by gold particles, increased with maturation of chondrocytes and was maximal in the zone of calcification. It was found in the cytoplasm of chondrocytes, osteoblasts and osteocytes, corroborating light microscope observations. The immunolabeling was associated with amorphous electron-dense material in the cytoplasm and not bound to membranes. There was moderate parvalbumin immunolabeling over the dense chromatin in the nuclei of chondrocytes and bone cells, but none in the cell processes of mature and hypertrophic chondrocytes, in the matrix vesicles themselves, or in the cell processes of osteoblasts. However, there was parvalbumin immunoreactivity in the cell processes of the osteocytes of compact cortical bone. The uncalcified and calcified matrix of the epiphyseal cartilage, the osteoid, and the fully mineralized cortical bone were devoid of parvalbumin immunoreactivity. Thus, immunoreactive parvalbumin is confined to the cell bodies of chondrocytes and osteoblasts, and is unlikely to be directly involved in mineral deposition. The maximal parvalbumin immunoreactivity in the last terminal chondrocytes of the zone of calcification suggests that the protein is involved in buffering intracellular Ca2+, preventing the stimulation of degenerative processes by high intracellular calcium. The parvalbumin immunoreactivity in the cell processes of osteocytes of compact cortical bone seems to indicate that this calcium-binding protein may be involved in the regulation of Ca2+ fluxes and hence in calcium homeostasis in bone.

Animals↗
PubMed2005

Densities of parvalbumin-immunoreactive neurons in non-malformed hippocampal sclerosis-temporal neocortex and in cortical dysplasias.

The changes in density of inhibitory parvalbumin-immunoreactive interneurons were quantitatively studied by immunohistochemistry in a series of human neocortical samples comprising the spectrum of malformations of cortical development (MCD) encountered in epilepsy surgery and the non-malformed hippocampal sclerosis-temporal neocortex in patients with refractory temporal lobe epilepsy. The highest relative density of parvalbumin-immunoreactive cells was obtained in the control samples (n = 21). The number of parvalbumin-immunoreactive neurons was significantly decreased in non-malformed hippocampal sclerosis-temporal neocortex (n = 73, 80.5% of control values). In a proportion of the latter samples as well as in two controls we observed patchy regions of absence of parvalbumin staining. The total counts of parvalbumin-immunoreactive cells in all the categories of MCD - "mild MCD" (n = 25), focal cortical dysplasia type I (n = 19) and type II (n = 15) - were decreased representing 72.4%, 55.0% and 12.2% of control values, respectively. Significantly different parvalbumin-immunoreactive cell densities were demonstrated between the focal cortical dysplasia types IIA and IIB. In "mild MCD", we observed a more pronounced decrease of parvalbumin-immunoreactive cells in the infragranular layers. No significant differences were revealed between the temporal and extratemporal examples of analogous MCD types. This study provides evidence for reduction of inhibitory parvalbumin-immunoreactive interneurons in the epileptic neocortex affected by MCD as well as in morphologically unaffected epileptic temporal neocortex, thus representing a possible mechanism for their epileptogenicity.

Adolescent↗
PubMed2005

In vivo gene transfer of parvalbumin improves diastolic function in aged rat hearts.

OBJECTIVE: Diastolic dysfunction is a characteristic finding of the aged mammalian heart. Parvalbumin acts as a Ca2+ sink and enhances relaxation in skeletal muscle, and overexpression of parvalbumin in myocardium increased cardiac relaxation in vitro as well as in vivo. Therefore, the objective of this study is to test the hypothesis that in vivo gene transfer of parvalbumin will improve diastolic dysfunction in aged rat heart. METHODS: We used adenovirus to transfer parvalbumin into two different rat models of aging: the Fischer 344 (F344) and the Fischer 344 x Brown Norway F1 hybrid (F344 x BN). Cardiac function was measured and compared after gene transfer. RESULTS: In vivo overexpression of parvalbumin in both rat aging models had no effect on systolic parameters but reduced left ventricular diastolic pressure and the time course of pressure decline. Overexpression of parvalbumin also improved the force frequency relationship in senescent rats. CONCLUSION: In vivo overexpression of parvalbumin improves diastolic dysfunction in two rat models of senescence, and this effect is independent of the rat strain investigated. The results show promise that gene therapy of parvalbumin may address the impaired Ca2+ homeostasis and diastolic dysfunction without an increase in energy expenditure.

Adenoviridae↗
PubMed2004

Repeated 4-aminopyridine seizures reduce parvalbumin content in the medial mammillary nucleus of the rat brain.

Parvalbumin (Pv) containing fast spiking neurons play a crucial role in synchronizing the activity of excitatory neuronal circuits in the brain. Alterations of parvalbumin content in these neurons can affect their spike characteristics and, ultimately, may increase the susceptibility of neuronal circuits to epileptic seizures. In the present study, we examined whether repeated 4-aminopyridine (4-AP)-induced seizures modify the regional parvalbumin contents in the rat brain. 4-Aminopyridine was injected intraperitoneally in adult rats, controls received the solvent. Animals were sacrificed at 3 h after a single acute treatment, or following repeated, daily treatments of 12 days. In situ hybridization (ISH) indicated significantly decreased parvalbumin mRNA level in the medial mammillary nucleus (MM) at 12 days. Western blotting revealed 20.1% significant decrease of parvalbumin content in the medial mammillary area, while parvalbumin immunohistochemistry indicated no change of the number of immunoreactive cells in the medial mammillary nucleus. The results reveal the downregulation of the transcription of the parvalbumin gene and the decrease of parvalbumin synthesis in medial mammillary nucleus neurons in response to experimental seizures.

4-Aminopyridine↗
PubMed2005

Mimotopes identify conformational epitopes on parvalbumin, the major fish allergen.

Parvalbumin, the major fish allergen, is recognized by allergen-specific IgE of more than 90% of all fish-allergic patients. A detailed knowledge of allergenic structures is crucial for developing a vaccine inducing blocking antibodies specifically directed towards the IgE binding epitopes. In the present study we aimed to use the phage display technique to generate mimotopes, which mimic epitopes on parvalbumin. Parvalbumin-specific IgE was purified from sera of fish-allergic patients and used for screening of a constrained decamer phage library. After four rounds of biopanning using parvalbumin-specific IgE, five phage clones were selected which were specifically recognized by parvalbumin-specific IgE as well as IgG. DNA sequencing and peptide alignment revealed a high degree of sequence similarities between the mimotopes. Interestingly, on the surface of natural parvalbumin three regions could be defined by computational mimotope matching. In accordance, previously defined allergenic peptides of cod parvalbumin highlighted areas in close proximity or overlapping with the mimotope matching sites. From the presented data we conclude that our approach identified conformational epitopes of parvalbumin relevant for IgE and IgG binding. We suggest that these mimotopes are suitable candidates for an epitope-specific immunotherapy of fish-allergic patients.

Allergens↗