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At least 811 records · Page 45Linked to original sources
PubMed1997

Developmental expression of parvalbumin by rat lower cervical spinal cord neurones and the effect of early lesions to the motor cortex.

Expression of calcium binding proteins (CaBPs), increasing neuronal activity and phases of synapse elimination are widely believed to be linked during development. We have employed immunocytochemistry to study the expression of the CaBP parvalbumin (PV) during the postnatal development of the lower cervical spinal cord and investigated how early lesions to the motor cortex, at the onset of corticospinal synaptogenesis, perturb the normal pattern of PV expression. This study confirms previous observations that in normal rats PV-like immunoreactivity is confined to large sensory afferents for at least 10 days postnatally (P10) and that the adult pattern of expression emerges from about P18 and involves mainly dorsal horn neurones. However, the study has also demonstrated a transient wave of expression in ventral horn neurones which reaches a maximum between P14-18 and declines thereafter. Unilateral lesions made at P7 to the forelimb motor cortex, which sends an almost completely crossed projection to the spinal cord, resulted in reduced neuronal expression of PV in the lower cervical spinal cord contralaterally at a range of ages (P14-31). The median ratio of PV positive neurones contralateral/ipsilateral to the lesion in spinal cord segments C7 and C8 was significantly lower (p < 0.01) at 56.0% (34.5-76.8 95% confidence limits, n = 14) than in sham operated controls (99.7%, range 93.7-113.6, n = 5). The lesion affected the transient wave of expression seen in ventral horn neurones during the third postnatal week as well as dorsal horn expression at older ages. We conclude that there is considerable plasticity in PV immunoreactivity during spinal cord development. PV is transiently expressed by ventral horn neurones at an age when movement control is functionally maturing. Early cortical lesions disrupt this transient phase of expression but also alter mature patterns of PV localisation. This suggests a critical role for corticospinal pathways in guiding maturation of segmental spinal cord circuitry.

Animals↗
PubMed1998

Postnatal development of parvalbumin immunoreactive amacrine cells in the rabbit retina.

In the adult rabbit, rat and cat retina, parvalbumin (PV) immunoreactivity is primarily localized to a population of narrow-field, bistratified amacrine cells, the AII amacrine cells-major interneurons of the rod pathway. This investigation examines the postnatal development of PV immunoreactivity in order to better understand the ontogeny of the AII amacrine cell population and the formation of the rod pathway. Rabbit retinas at various postnatal ages were processed for immunohistochemistry using a monoclonal antibody directed to PV and analyzed morphometrically. On the day of birth, PV immunoreactive cell bodies are numerous in the proximal inner nuclear layer (INL) in all retinal regions. These cells have a primary process directed towards the inner plexiform layer (IPL). At postnatal day (PND) 2, a few faint immunoreactive processes are observed in the IPL. At PND 4, well-stained processes are observed to ramify mainly in the proximal IPL. At PND 6, strongly immunoreactive processes are present in both the distal and proximal IPL, and at PND 10 they form a continuous, dense plexus in both levels of the IPL. By PND 10, the morphology of PV immunoreactive cells is similar to PV immunoreactive cells in adult retinas. The density of PV immunoreactive cells in the proximal INL increases from PND 2 to PND 5, then it gradually decreases to adult values, while the total number of PV immunoreactive cell bodies increases until PND 10. PV immunoreactive amacrine cells at PND 2, as in the adult, are nonrandomly distributed across the retinal surface. These studies show that PV immunoreactive amacrine cells have a developmental profile that is similar to several other amacrine cell types. This includes the elaboration of processes in the IPL during the first postnatal week and a mature appearance towards the end of the second week of life, about the time of eye opening. These observations indicate that the AII amacrine cell may participate in the processing of visual information at eye opening.

Aging↗
PubMed2002

Different regulatory sequences are required for parvalbumin gene expression in skeletal muscles and neuronal cells of transgenic mice.

Parvalbumin (PV) is expressed in fast-twitch fibers in skeletal muscles and a subpopulation of inhibitory neurons in the CNS. We generated transgenic mice that expressed the human interleukin-2 receptor alpha-subunit-green fluorescent fusion protein (hIL-2R-GFP) using two types of PV transgene. One contained the hIL-2R-GFP gene downstream of a 16.5-kb 5'-upstream PV genomic sequence (PV line). The other comprised the hIL-2R-GFP gene in bacterial artificial chromosome (BAC) with either a 180-kb (PA line) or 155-kb (PB line) insert encompassing the PV gene. Independent lines of all transgenic mice showed a faithful hIL-2R-GFP expression in fast-twitch muscle fibers. However, appreciable hIL-2R-GFP expression in the CNS occurred only in the PA transgenic lines. In one line of PA transgenic mice, hIL-2R-GFP was properly expressed in PV-containing neurons in the cerebellum, thalamic reticular nucleus, globus pallidus and cerebral cortex, though ectopic expression was observed in a particular subset of cerebellar astrocytes. Another line of PA transgenic mice showed a selective and mosaic expression of hIL-2R-GFP in PV-containing Purkinje, basket and stellate cells in the cerebellum. These results indicate that the 16.5-kb PV genomic sequence is sufficient for fiber-type-selective transcription but additional regulatory sequences comprised in BAC DNA are required for proper expression in PV-containing neurons.

Animals↗
PubMed1979

Calcium and magnesium binding by parvalbumin. A proton magnetic resonance spectral study.

Proton magnetic resonance spectroscopy has been used to monitor the kinetics and nature of the conformational transitions induced by binding of calcium and magnesium to carp parvalbumin. Rate constants have been determined for the exchange between the cation dependent conformational states of the protein in solution. These data enable a description of the kinetics and mechanism controlling the calcium flux in vivo during contraction.

Animals↗
PubMed1979

Binding of calcium by fragment 38-108 of pike parvalbumin.

Cyanogen bromide splitting of pike parvalbumin III was carried out and fragment 38-108 containing two calcium-binding domains was isolated. The obtained fragment binds calcium rather well (Kd = 1.6.10(-5) M), possesses a secondary structure, its CD spectrum changes after removal of calcium.

Amino Acid Sequence↗
PubMed1979

NMR studies of primary and secondary sites of parvalbumins using the two paramagnetic probes Gd (III) and Mn (II).

The binding of cations by parvalbumins was studied by the proton relaxation enhancement (PRE) method using the paramagnetic probes Gd(III) and Mn(II). Gd(III) appears as a specific probe of the primary sites CD and EF with the following binding parameters: n = 2, KdGd = 0.5 x 10(-11) M and epsilon b = 2.3. The low value of epsilon b is the result of a nearly complete dehydration of the protein bound ions. Competition experiments between Gd(III) and various diamagnetic cations show the following order of affinity for the EF and CD sites: Mg2+ less than Zn2+ less than Sr2+ less than Ca2+ less than Cd2+ less than La3+ less than or equal to Gd3+. Mn 2+ is a specific probe of a secondary site with the following binding parameters: n = 1, KdMn = 0.6 x 10(-3) M and epsilon b = 17. The high value of epsilon b suggests that the protein bound Mn(II) has retained most of its hydration shell. Competition experiments between (Mn(II) and different cations show similar affinities for this site: Ca2+ less than or equal to Mg2+ less than or equal to Cd2+ less than or equal to Mn2+. This secondary site is located near the EF primary site.

Animals↗
PubMed2000

Identification of the primary auditory field in archival human brain tissue via immunocytochemistry of parvalbumin.

Using parvalbumin (PV)-immunocytochemistry, we identified the human primary auditory field (PAF) for the first time. The first gyrus of the right Heschl was identified, and a serial perpendicular cut to the gyrus was made. PV-immunoreactive neuropils delineated four zones, as have been described in monkeys. Unlike with conventional staining, zone 1, characterized by intense immunostaining, corresponded to the koniocortex (PAF), while zone 2, characterized by moderate immunostaining around zone 1, to the parakoniocortex. PV-immunocytochemistry was a useful way to identify PAF in formaline-fixed archival human brain tissue.

Aged↗
PubMed1998

Co-localization of calretinin and parvalbumin with nicotinamide adenine dinucleotide phosphate-diaphorase in tench Mauthner cells.

The co-localization of calretinin (CR) and parvalbumin (PV) immunoreactivity with nicotinamide adenine dinucleotide phosphate-diaphorase (ND) activity was analyzed in the Mauthner cells of the tench. Mauthner cells were ND active, and ND staining was observed in the soma, axon cap region, and axon of these neurons. CR co-localized with ND in the axon of the Mauthner cells but not in the cell body or in the dendrites, whereas PV immunoreactivity co-localized with ND in the soma, axon and dendrites. The presence of two different calcium-binding proteins in the Mauthner cells indicates that these neurons need complex calcium-buffering systems. The co-localization of these calcium-binding proteins with ND might suggests their involvement in nitric oxide-related events.

Animals↗
PubMed2003

Ultrastructural study of gap junctions between dendrites of parvalbumin-containing GABAergic neurons in various neocortical areas of the adult rat.

Parvalbumin (PV)-containing GABAergic neurons in the hippocampus form dual networks linked by both dendrodendritic gap junctions and mutual inhibitory synapses. Recent physiological studies have demonstrated similar functional connectivity among cortical GABAergic neurons, but the corresponding structures have not been fully analyzed at the electron microscopic level. In this study we examined detailed ultrastructural features of gap junctions between PV neurons in the mature neocortex. Light microscopic observations and confocal laser scanning microscopy revealed frequent dendrodendritic contacts between PV neurons. Electron microscopic analysis provided direct morphological evidence for the existence of gap junctions between 22 pairs of PV-immunoreactive dendrites in the visual, auditory, and somatosensory cortices. Their ultrastructural features that were characteristic of immunolabeled profiles were consistent with the general structure of gap junctions. In one case a gap junction coexisted with a dendrodendritic chemical synapse, making a mixed synapse. Importantly, we also encountered a gap junction between PV positive and negative, presumptive non-principal cell-derived, dendrites. Quantitative analysis was made in 16 pairs of PV positive dendrites forming gap junctions in the infragranular layers of the somatosensory cortex. Diameters of these dendrites ranged from 0.3 to 2.7 microm, suggesting diverse locations of gap junctions along the proximal-distal axis of dendritic trees, but the majority (81%) were less than 1 microm. The mean size of gap junctions along apposing membranes was 0.22+/-0.09 microm. By using this size, the theoretical value of a junctional conductance was estimated to be 2.1-5.3 nS. Dendrites of PV neurons in the infragranular layers of the somatosensory cortex were reconstructed light microscopically and the sites of contacts with other PV neurons were mapped. Although these contacts do not necessarily imply gap junctional coupling, their number (5.3+/-2.3 per cell, n=11) suggested the degree of connectivity of less than 10 coupling from single PV neurons with others. Sholl analysis revealed that only 38% of their dendrites occurred within 200 microm from the soma. The present study demonstrated detailed ultrastructural features of gap junctions between mature cortical PV neurons. These features will facilitate not only identification of gap junctions in variously labeled neurons but also analysis of their functional aspects by enabling theoretical estimate of their junctional conductances.

Animals↗
PubMed1998

Distribution of calbindin D-28k and parvalbumin neurons and fibers in the rat basal ganglia.

This review deals with the distribution of immunoreactivity for calbindin D-28k (CB) and parvalbumin (PV) in the different nuclei of the rodent basal ganglia analyzed with the data available after the use of single and double antigen procedures applied to single sections. These findings reveal that CB and PV are distributed according to a highly heterogeneous pattern in the caudate putamen complex (CPu), globus pallidus (GP), entopeduncular nucleus (EP), subthalamic nucleus (STh) and substantia nigra (SN) of the rat. In each basal ganglia structure, the two calcium-binding proteins label different neuronal subsets. Therefore, the use of CB and PV immunohistochemistry may be considered as an excellent tool to define distinct chemoarchitectonic and functional domains within the complex organization of the basal ganglia. Double immunohistochemical methods are also useful to illustrate the relationships between the different chemical subdivisions of the CPu, GP, EP, STh and SN and the chemically characterized connections with each other and with other forebrain and brainstem structures. However, specific rules should be followed when combining single and double immunostaining procedures, and the results of such studies must be evaluated with caution. When they are used properly, these methods can reveal hitherto unknown principles of organization of the basal ganglia and thus shed new light on the anatomical and functional organization of this set of subcortical structures involved in the control of motor behavior.

Animals↗
PubMed2001

Onset of calbindin-D 28K and parvalbumin expression in the lateral geniculate complex and olivary pretectal nucleus during postnatal development of the rat.

The onset and distribution of calbindin (CB) and parvalbumin (PV) immunoreactivity were investigated in the lateral geniculate nuclear complex and the olivary pretectal nucleus (OPT) in developing rats. CB expression occurred early (before eye-opening) in the relay neurons of the intergeniculate leaflet, parvocellular portion of the ventral lateral geniculate nucleus and OPT relating to ambient vision mediated by W-like retinal ganglion cells. On the contrary, PV expression occurred late (after eye-opening) in the relay neurons of the magnocellular portion of the ventral lateral geniculate nucleus (VLGMC) and OPT relating to focal vision mediated by Y-like retinal ganglion cells. A unilateral eye enucleating experiment indicated that the VLGMC and OPT received dense input from PV-positive Y-like retinal ganglion cells. The results show the different onsets of CB and PV expressions in the retino-recipient thalamic and pretectal nuclei receiving inputs from different kinds of retinal ganglion cells.

Aging↗
PubMed2002

Postnatal development of parvalbumin and calbindin D-28k immunoreactivities in the canine anterior cingulate cortex: transient expression in layer V pyramidal cells.

We have examined the ontogeny of parvalbumin (PV) and calbindin D-28k (CB) immunoreactivities in the canine anterior cingulate cortex (ACC) from the day of birth (P0) through P180. At P7, PV immunoreactivity first appeared in layer VI multipolar cells. The PV immunoreactivity in GABAergic nonpyramidal cells appeared to follow an inside-out gradient of radial emergence. Although immunoreaction was limited mainly to the developing nonpyramidal cells, pyramid-like PV immunoreactive cells were transitorily observed in layer V from P14 to P90. The developmental pattern of CB immunoreactivity differed from that of PV immunoreactivity. CB immunoreactivity first developed in layer V pyramidal cells from P0, which continued through P90. CB immunoreactive nonpyramidal cells were located in the infragranular layers and white matter at P0 and matured in both the supragranular and infragranular layers without clear inside-out gradient. This developmental study revealed the comparable belated expression of PV immunoreactivity and the transient expression of both calcium-binding proteins in layer V pyramidal cells. These results suggest that the transient expression of calcium-binding proteins in layer V pyramidal cells might be related to the critical period of early postnatal development.

Aging↗
PubMed2000

Effect of neonatal ethanol exposure on parvalbumin-expressing GABAergic neurons of the rat medial septum and cingulate cortex.

This study was performed to determine the long-term effects of ethanol exposure during the brain growth spurt (postnatal days 4-10) on the number of parvalbumin-immunoreactive (PA+) GABAergic neurons in the adult (P60) rat medial septum and anterior cingulate cortex. Significant loss of neurons within each of these populations has previously been demonstrated following prenatal ethanol exposure. In the present study, no significant differences in the number of PA+ neurons were found in either the medial septum or the cingulate cortex when control and ethanol-exposed animals were compared. The cellular densities and volumetric measures in both brain regions were also similar in the two groups. We speculate that compensatory up-regulative mechanisms may have accounted for the protection of the PA neuronal populations in these two areas following the early neonatal exposure.

Animals↗
PubMed2001

Parvalbumin-containing interneurons of the human cerebral cortex express nicotinic acetylcholine receptor proteins.

Cholinergic fibers from the basal forebrain are known to contact cholinoceptive cortical pyramidal neurons. Recent electrophysiological studies have revealed that nicotinic acetylcholine receptors are also present in human cerebrocortical interneurons. A direct visualization of nicotinic receptor subunits in cortical interneurons has, however, not yet been performed. We have applied double-immunofluorescence using antibodies against parvalbumin --a marker for the Chandelier and basket cell subpopulation of interneurons--and to the alpha4 and alpha7 subunit proteins of the nicotinic acetylcholine receptor. The vast majority of the parvalbuminergic interneurons was immunoreactive for the alpha4 and the alpha7 nicotinic acetylcholine receptor. Provided these receptors would be functional--as suggested by recent electrophysiological findings--the connectivity pattern of cholinergic afferents appears much more complex than thought before. Not only direct cholinergic impact on cortical projection neurons but also the indirect modulation of these by cholinergic corticopetal fibers contacting intrinsic cortical cells would be possible.

Adult↗
PubMed2002

Parvalbumin-containing interneurons in rat hippocampus have an AMPA receptor profile suggestive of vulnerability to excitotoxicity.

alpha-Amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors mediate excitatory neurotransmission in the central nervous system, and contain combinations of four subunits (GluR1-4). We developed a GluR3-specific monoclonal antibody and quantified the cellular distribution of GluR3 in rat hippocampus. GluR3 immunoreactivity was detected in all pyramidal neurons and most interneurons. In addition, we found a subset of parvalbumin (PV)-containing interneurons in the hippocampus and neocortex that was notable for its intense GluR3 immunoreactivity and lack of GluR2 immunoreactivity. Such an expression pattern of AMPA receptor subunits is likely to make these interneurons selectively vulnerable to excitotoxicity.

Animals↗
PubMed2003

Light experience induces differential asymmetry pattern of GABA- and parvalbumin-positive cells in the pigeon's visual midbrain.

The formation of functional and morphological asymmetries within the pigeon's tectofugal system depends on left-right differences in visual input during embryonic development. This asymmetric stimulation presumably affects activity-dependent differentiation processes within the optic tectum. Behavioral studies reveal that prehatch light stimulation asymmetry influences both left- and right-hemispheric processes in a differential way. Thus, we have to assume divergent effects on both hemispheres. This study represents an attempt to test the hypothesis that embryonic light asymmetry induces different, cell-type-specific effects in the left and the right optic midbrain. Since it is likely that inhibitory interneurons play a critical role in the establishment of asymmetries, we examined in both sides of the brain the soma sizes of GABA- and parvalbumin- (PV) immunoreactive (ir) cells of the tectum and the magnocellular isthmic nucleus in controls and in dark-incubated animals. No cell size asymmetries of magnocellular isthmic neurons were found in either dark-incubated or control birds. Dark-incubation also prevented the establishment of lateralized differences in GABAergic and PV-positive tectal cells. However, in control birds GABAergic cells displayed larger somata in the left tectum, whereas PV-ir neurons were enlarged within the right tectum. This complementary asymmetry pattern suggests that PV- and GABA-ir tectal cells represent different cellular populations which react differently to visual input. Thus, our data show that visual lateralization does not result from a mere growth promoting effect that enhances differentiation within the behaviorally dominant left side, but is constituted by different cell type-specific circuits which are divergently adjusted in the left and in the right tectum.

Animals↗
PubMed1997

Colocalization of parvalbumin, calretinin and calbindin D-28k in human cortical and subcortical visual structures.

Several studies have demonstrated that three calcium-binding proteins parvalbumin (PV), calbindin D-28k (CB) and calretinin (CR) mark distinct subsets of cortical interneurons. This study demonstrates, in cortical and subcortical visual structures, the coexistence of two calcium-binding proteins in some neuronal subpopulations. The human visual cortex (VC), lateral geniculate nucleus (LGN). lateral inferior pulvinar (LIP) and superior colliculus (SC) were examined by a double-labelling immunocytochemical technique. The VC showed mostly separate populations of PV, CB and CR immunoreactive (-ir) interneurons, but also small populations of double-stained PV + CR and CR + CB neurons, while PV + CB neurons were less frequent. An average of 2.5% of the immunoreactive neurons were double-stained for PV + CR and 7.1% for CR + CB in area 17, while this percentage was slightly higher in association area 18 (3.3 and 7.4%, respectively). In the LGN and LIP, double-stained neurons were scarce, but in the fibre capsule of these nuclei, as well as in the optic radiation (OR) and white matter underlying area 17, both double-stained PV + CR or CR + CB and separate populations of PV-ir, CB-ir and CR-ir neurons and fibres were observed. Unlike the thalamic regions, the SC showed some double-stained PV + CR and CR + CB neurons, scattered both in the superficial and deep layers. These findings are discussed in the light of similar observations recently reported from other regions of the human brain.

Adult↗
PubMed1997

Calretinin- and parvalbumin-immunoreactive neurons in the rat main olfactory bulb do not express NADPH-diaphorase activity.

The presence of nitric oxide synthase (NOS) in neuronal elements expressing the calcium-binding proteins calretinin (CR) and parvalbumin (PV) was studied in the rat main olfactory bulb. CR and PV were detected by using immunocytochemistry and the nitric oxide (NO) -synthesizing cells were identified by means of the reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase) direct histochemical method. The possible coexistence of NADPH-diaphorase and each calcium-binding protein marker was determined by sequential histochemical-immunohistochemical double-labeling of the same sections. Specific neuronal populations were positive for these three markers. A subpopulation of olfactory fibers and olfactory glomeruli were positive for either NADPH-diaphorase or CR. In the most superficial layers, groups of juxtaglomerular cells, superficial short-axon cells and Van Gehuchten cells demonstrated staining for all three markers. In the deep regions, abundant granule cells were NADPH-diaphorase- and CR-positive and a few were PV-immunoreactive. Scarce deep short-axon cells demonstrated either CR-, PV-, or NADPH-diaphorase staining. Among all these labeled elements, no neuron expressing CR or PV colocalized NADPH-diaphorase staining. The present data contribute to a more detailed classification of the chemically- and morphologically-defined neuronal types in the rodent olfactory bulb. The neurochemical differences support the existence of physiologically distinct groups within morphologically homogeneous populations. Each of these groups would be involved in different modulatory mechanisms of the olfactory information. In addition, the absence of CR and PV in neuronal groups displaying NADPH-diaphorase, which moreover are calmodulin-negative, indicate that the regulation of NOS activity in calmodulin-negative neurons of the rat olfactory bulb is not mediated by CR or PV.

Animals↗