Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Parvalbumins”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed2006

Influence of the "open field" exposure on calbindin D28K, calretinin, and parvalbumin containing cells in the rat midbrain - developmental study.

The aim of our study was to analyze the influence of the open field (OF) exposure on: 1. Distribution of c-Fos positive nuclei in: ventral tegmental area, substantia nigra, periaqueductal gray. 2. Appearance of calbindin-D28k, calretinin and parvalbumin in midbrain neurons that are engaged in the stress response. 3. Changes of c-Fos and calcium-binding proteins expression during maturation. The material consisted of Wistar rats of age between 0 and 90 days. The OF exposure was applied throughout 10 min and 90 min before the death of the animals. The brain sections were double stained using the antibodies against c-Fos, CB, CR or PV. Our results showed that in all studied nuclei age-related increase of c-Fos expression (without changing of its distribution properties) was found. PV didn't show any co-localization with c-Fos in neurons of studied regions at any ages, however some PV-immunoreactive (PV-ir) basket-like structures around c-Fos-immunoreactive (c-Fos-ir) neurons were observed. In the youngest group of rats c-Fos-ir cells and cells immunoreactive for CB and CR constituted separate neuronal populations. During maturation increases in the level of their co-localization with c-Fos was observed. We may conclude that in adult rat midbrain structures CB-immunoreactive (CB-ir) and CR-immunoreactive (CR-ir) cells (probably projection neurons) are mainly activated in the stress response following OF exposure. In the contrary PV-ir cells has only an indirect (modulatory) influence upon the c-Fos-ir cells.

Animals↗
PubMed1991

Morphology of neurons in the rat basal forebrain nuclei: comparison between NADPH-diaphorase histochemistry and immunohistochemistry of glutamic acid decarboxylase, choline acetyltransferase, somatostatin and parvalbumin.

Transversal sections through the basal forebrain of 11 adult male rats were immunostained for glutamic acid decarboxylase (GAD), choline acetyltransferase (ChAT), somatostatin (SOM) and parvalbumin (PARV). Immunohistochemistry of ChAT, PARV, and SOM was combined with histochemistry of NADPH-diaphorase (NADPH-d) to obtain information on the colocalization of various neuroactive substances and this enzyme and to facilitate the recognition of morphological details of double-stained neurons. The distribution patterns of GAD- and PARV-immunoreactive cells were only in part congruent in basal forebrain nuclei in the rat. In the medial septal nucleus (MS) and the vertical limb of the diagonal band (vDB) PARV-immunopositive neurons were homogeneously scattered inside the nucleus, whereas the GAD-immunoreactive cells were much more numerous in the lateral part of this nuclear complex. In the horizontal limb of the diagonal band (hDB) and the nucleus preopticus magnocellularis (NPM), where GAD-immunoreactive cells occurred in high number, only very few cells contained PARV-immunoreaction product. In the substantia innominata-nucleus basalis Meynert complex (SI-NB) and in the ventral pallidum (VP) the neuropil was heavily stained with the GAD-immunoreaction product. The number of GAD-positive cells appeared low in the SI-NB, but much higher in the VP. In this nucleus GAD- and PARV-immunoreactive cells seem to be identical. PARV-positive neurons are very sparse in the SI-NB. Double-staining of PARV-immunoreactivity and NADPH-d was not registered. These nuclei were the only ones in which some cells with SOM-like immunoreactivity were observed. Among ChAT-positive neurons those double-stained with NADPH-d occurred in moderate number, but with obvious regional differences. In MS-vDB and the marginal zone of hDB the two neuron groups were intermingled, but only in the innermost part of the hDB ChAT-single-immunostained cells form aggregates, which were also typical of the zone in the SI-NB that surrounds and infiltrates the globus pallidus (GP). Double-labelled cells were more frequent in the lateral aspect of the NPM and SI-NB. Cells single-stained for NADPH-d were frequent in the MS-vDB along the border toward the lateral septal nuclei, but low in number in the NPM, VP and SI-NB. The functional aspects of the occurrence of GAD-immunoreactive cell aggregates in the lateral preoptic area (LP) and the lateral hypothalamic area (LH) were discussed with special regards to extrinsic GABAergic input in the dorsal SI-NB.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

[Stereological analysis of GABAergic neurons and calcium binding protein parvalbumin-containing neurons in the rat somatosensory cortex].

The number of neuronal cells in the rat somatosensory cortex (barrel area) has been estimated by a stereological method, disector, using pairs of toluidine-blue stained plastic embedded 0.5 microns thick sections, 3.0 microns distant from each other. Chemical properties of those disector-counted cells were further revealed by applying postembedding immunocytochemical methods on adjacent semithin sections. Thus we analysed quantitatively the number, distribution and proportion of three types of neurons: 1) GABA negative neurons, 2) GABA-like immunoreactive (GABA-LIR) neurons and 3) a specific calcium binding protein parvalbumin (PV) immunoreactive (PV-IR) neurons, which are a subpopulation of GABA-LIR neurons. The densities of total neurons in the rat somatosensory cortex were 55 x 10(3)/mm3. Of neurons 24% and 12% were GABA-LIR and PV-IR, respectively; almost all PV-IR neurons are GABA-LIR and thus about 50% GABA-LIR neurons are PV positive. The number of total neurons under a unit surface area 1mm2 through the thickness of the somatosensory cortex is 85 x 10(3). GABA-LIR neurons were 20 x 10(3) and PV-IR neurons and PV negative GABA-LIR neurons were 10 x 10(3) and 10 x 10(3), respectively. The laminar distribution of each group of neurons shows prominent differences, indicating that the neuronal composition was different from layer to layer. The density of GABA-LIR neuron was highest in layer IV and especially PV-IR neurons were 2-3 times more numerous in layer IV than in layer II/III, V and VI.

Animals↗
PubMed1989

Immunocytochemical study of parvalbumin fibers and cell bodies in the rat hipothalamus.

The distribution of parvalbumin (PA) cell bodies and fibers in the hypothalamus of the rat was studied using a monoclonal antibody and the avidin-biotin-peroxidase method. The densest clusters of immunoreactive perikarya were observed in the nuclei mamillare medialis, arcuatus and dorsomedialis hypothalami, whereas the corpus mamillare lateralis had the lowest density. The densest network of immunoreactive fibers was observed in the corpus mamillare lateralis and nucleus arcuatus. The corpus mamillare medialis contained a moderate number of PA fibers, whereas the nucleus dorsomedialis hypothalami had the lowest density of immunoreactive fibers. In addition, a large number of immunoreactive fibers was found in the tractus opticus and the tractus mamillo-thalamicus. Essentially, the distribution of PA in the rat hypothalamus after using a monoclonal antibody seems to be broader in comparison with previous studies carried out in the same diencephalic region of the rat. The presence of PA in several nuclei of the rat hypothalamus suggests that this protein could be directly or indirectly involved in neuroendocrine, limbic and visual functions.

Animals↗
PubMed1987

Isolation and sequence of a cDNA clone for rabbit fast skeletal muscle troponin C. Homology with calmodulin and parvalbumin.

The binding of Ca2+ to troponin C (TnC) regulates skeletal muscle contraction. We have isolated a full-length cDNA clone for fast skeletal muscle TnC from a neonatal rabbit skeletal muscle library and determined its nucleic acid sequence. The amino acid sequence deduced from this clone matches the previously reported amino acid sequence (Collins, J. H., Greaser, M. L., Potter, J. D., and Horn, M. J. (1977) J. Biol. Chem. 252, 6356-6362) except at the amino terminus. According to the nucleotide sequence, the first 2 residues of TnC are threonine-aspartic acid, which is the reverse of the order reported previously. The isolation of the adult form of TnC from a neonatal library suggests that there may be no developmental isoforms of fast TnC. The protein coding region of the fast TnC clone has 67% homology with the reported nucleotide sequence for chicken slow TnC (Putkey, J. A., Carroll, S. L., and Means, A. R. (1987) Mol. Cell. Biol. 7, 549-1553). The homologies between the nucleotide sequences of TnC, calmodulin, and parvalbumin provide evidence that all three proteins were derived from a common precursor molecule which had four Ca2+-binding sites.

Animals↗
PubMedDate not supplied

[Isolation of the calcium-binding domain of carp parvalbumin].

Carp parvalbumin has two calcium-binding domains with a similar three-dimensional structure. Using the tryptic hydrolysis at the arginine residue in position 75, it was possible to split off one calcium-binding domain. All lysine residues were protected by maleic groups which were removed at the final stage. The domain (with a peptide thirty-three residues) isolated by ion-exchange chromatography and gel filtration does not have a secondary structure in a solution and is unable to bind calcium.

Amino Acids↗
PubMed1982

Observation of the 43Ca NMR signals from Ca2+ ions bound to calmodulin, parvalbumin, and troponin C.

Through the combined use of isotopically enriched 43Ca2+, high magnetic field, Fourier transform techniques, and a high-performance probe, the 43Ca NMR signals from ions bound to three proteins have been observed. These proteins are calmodulin, parvalbumin, and troponin C. Both longitudinal (1/T1) and transverse (1/T2) relaxation rates were measured for protein-bound 43Ca2+, and the quadrupole coupling constant and correlation time were obtained from these data. The calculated correlation times are in good agreement with the rotational correlation time for the entire protein molecules, which indicates that the Ca2+-binding sites are relatively rigid.

Animals↗
PubMed1993

Metal binding properties of recombinant rat parvalbumin wild-type and F102W mutant.

Rat parvalbumin (PV), an EF-hand type Ca(2+)-binding protein, was expressed in Escherichia coli and mutated by replacing a Phe at position 102 with a unique Trp in order to introduce a distinct fluorescent label into the protein. Mass spectroscopy and NMR data indicate that the recombinant wild-type (PVWT) and F102W mutant (PVF102W) proteins have the expected molecular weight and retain the native structure. Both proteins contain two non-cooperative Ca2+/Mg(2+)-binding sites with intrinsic affinity constants, KCa and KMg, of 2.4 +/- 0.9 x 10(7) M-1 and of 2.9 +/- 0.2 x 10(4) M-1, respectively, for PVWT, and KCa and KMg, of 2.7 +/- 1.1 x 10(7) M-1 and of 4.4 +/- 0.3 x 10(4) M-1, respectively, for PVF102W. Based on the highly similar metal binding properties of PVWT and PVF102W the latter protein was used to study cation-dependent conformational changes. Trp fluorescence emission and UV difference spectra of PVF102W indicated that the Trp residue at position 102 is confined to a hydrophobic core and conformationally strongly restricted. Upon Ca2+ or Mg2+ binding the structural organization of the region around the Trp is hardly affected, but there are significant changes in its electrostatic environment. The conformational change upon binding of Ca2+ and Mg2+, as monitored by UV difference spectrophotometry, increases linearly from 0 to 2 cations bound, indicating that the binding of both ions contributes equally to the structural organization in this protein.

Animals↗
PubMed1996

Distribution patterns of Wisteria floribunda agglutinin binding sites and parvalbumin-immunoreactive neurons in the human visual cortex: a double-labelling study.

Extracellular lattic-like coatings--known as perineuronal nets (PNs)--ensheath certain types of neurons in the mammalian neocortex. PNs and densely stippled zones in some cortical layers contain proteoglycans stainable e.g. with several plant lectins. The present study is focused on the binding sites of the plant lectin Wisteria floribunda agglutinin (WFA) and on its relationship to parvalbumin-immunoreactive (PARV-ir) neuronal constituents in the human visual cortical fields 17 and 18. Size and numbers of PNs varied not only between these two areas, but also between its layers. In area 17 the PNs appeared accumulated in two conspicuous bands which included layer IV, particularly layer IVb, and layer VI. Layer IVc of area 17 contained numerous small faintly stained PNs. In area 18 a two-tiered organization of PNs in layers IIIb-c and layer V was emphasized. The neuropil staining by WFA was much more intense in layers IIIb-c of area 18 than of area 17. In areas 17 and 18 the vast majority of PNs was associated with sub-populations of PARV-ir cells resembling several classes of GABAergic cortical interneurons. Among PARV-negative cells surrounded by PNs, only exceptionally pyramide-like neurons were detected. The patterns of lectin-labelling in the human visual primary and association cortex resembled those of macaque monkeys and differed from those in the visual cortex of rat and gerbil. These differences between mammals representing divergent modes of visual specialization may support the view that such extracellular matrix components in these occipital cortical areas are involved in visual information processing subserving fast inhibitory interneuronal actions.

Agglutinins↗
PubMed1996

Parvalbumin in the human anterior cingulate cortex: morphological heterogeneity of inhibitory interneurons.

The calcium-binding protein parvalbumin (PV) is a marker for a certain subset of GABAergic cortical interneurons. In the present study, indirect immunocytochemistry with an antibody against PV was performed on serial sections of human anterior cingulate cortex (Brodmann's area 24), an important relay centre of the limbic system. PV-positive structures are distributed in a layer- and cell type-specific manner. Based on morphological features and laminar distribution pattern, PV-immunoreactive interneurons are subdivided into eight different classes. PV immunoreactivity within the neuropil comprises dendritic and axonal processes. Area 24 contains two densely immunolabelled neuropil bands in layers III and Vb. Axon cartridges are preferably located in layers V and VI. The results provide a "PV immunoarchitecture' as a basis for further studies of PV immunoreactivity under pathological conditions. PV is assumed to play a role in maintaining calcium homeostasis in nerve cells, and to modulate neuronal excitability and resistance to biochemical damage. On the other hand, PV immunoreactivity has recently been shown to undergo characteristic changes during different stages of brain maturation. Therefore, examination of PV-positive structures will provide new insights into cortical circuitry in neurodegenerative as well as neurodevelopmental disorders.

Adult↗
PubMed1997

Prenatal development of calbindin D-28K and parvalbumin immunoreactivities in the human retina.

Two calcium binding proteins, calbindin D-28K (CB) and parvalbumin (PV),immunoreactivities were examined by immunocytochemistry in the retinas of human fetuses aged from 13 weeks (W) of gestation to term. CB- and PV-immunoreactive products were both detectable at 13 W and appeared in all layers in a roughly inside-out order by 24 W. PV-immunostaining occurred in virtually all ganglion cells, most horizontal cells, and a few amacrine cells. CB-immunoreactivity was found in most amacrine cells and some horizontal cells, and a subset of cells in the ganglion cell layer that were more frequent in the nasal than the temporal retina at 13-15 W. Bipolar cells were distinctly immunostained for CB by 24 W. Foveal cones showed faint CB labeling by 24 W and intense staining at 32 W. The patterns of CB- and PV-immunoreactivities by birth were similar to those at 32 W with the addition of faint CB-immunolabeling occurring beyond the fovea in the photoreceptors. A stronger expression of CB was seen in the nasal side of the optic nerve head from 13-24 W, peaking at 15 W. The results indicate that CB and PV expression in ganglion cells and inner nuclear layer neurons proceeds in parallel with their somal and process differentiation, suggesting a possible role for these proteins in neuronal maturation. The early expression of PV and CB in ganglion cell axons might be related to optic nerve outgrowth, including path-finding at the optic chiasm. CB expression in cones and other cells in the fovea may indicate that it is involved in foveal formation that occurs during the perinatal period.

Calbindins↗
PubMed1997

Comparison of the distribution of parvalbumin-immunoreactive and other synapses onto the somata of callosal projection neurons in mouse visual and somatosensory cortex.

The distribution of synapses made by parvalbumin-immunoreactive (pv-ir) and nonimmunoreactive terminals was determined for the cell bodies of callosal projection neurons in the somatosensory and visual areas of mouse cerebral cortex. Callosal neurons were labeled by the retrograde transport of horseradish peroxidase applied to the contralateral hemisphere. The surface areas of somata belonging to callosal cells in somatosensory cortex ranged from 230 to 243 microm2 in size and received roughly one-third of their synapses from pv-ir terminals. Visual cortex, in contrast, contained two populations of callosal cell bodies: relatively large ones ranging in size from 255 to 279 microm2 that received 3-9% of their synapses from pv-ir terminals and smaller cell bodies that both in size (232-237 microm2) and in the proportion of synapses received from pv-ir terminals resemble the callosal cells examined in somatosensory cortex. That different functional areas of the cortex have populations of callosal cells similar in size, and displaying similar patterns of somatic synapses, supports the notion that a common plan of synaptic connectivity characterizes different functional areas. Results in visual cortex indicate that functional areas contain, in addition, area-specific patterns of synapses.

Animals↗
PubMed1997

Distribution of neurons immunoreactive for parvalbumin and calbindin in the somatosensory thalamus of the raccoon.

The aim of this study was to assess the distribution of neurons immunoreactive for parvalbumin (PV), calbindin (CaBP), glutamic acid decarboxylase (GAD), and gamma-aminobutyric acid (GABA) in the somatosensory thalamus of the raccoon and to compare these features to those of other species, especially primates. Immunohistochemistry was used to study the location of these neurons in the ventroposterior nucleus (VP), ventroposterior inferior nucleus (VPI), posterior group of nuclei (Po), and reticular nucleus (Rt). A consistent differential pattern of PV-positive (PV+) and CaBP-positive (CaBP+) cells was found in the somatosensory thalamus. Many PV+ neurons were observed in VP and Rt, but very few were found in VPI or Po. In contrast, CaBP+ neurons were distributed throughout VP, VPI, and Po but were very sparse or absent in Rt. In the VP nucleus, PV+ cells were distributed in clusters separated by interclusteral regions with a sparse distribution of PV+ cell bodies. The distributions of PV+ and CaBP+ cells tended to be complementary to each other in VP; regions with a high density of PV+ neurons had a low density of CaBP+ cell bodies. Double-labeling experiments revealed very few neurons in which PV and CaBP immunoreactivities were colocalized. Cells immunoreactive for GAD or GABA were found in PV-dense clusters of VP; fewer GABAergic neurons were present in the CaBP-dense interclusteral regions of VP and in VPI and Po. GAD+ and GABA+ neurons were most prominently distributed in Rt. We conclude that the distributions of PV+ and CaBP+ cell bodies in the raccoon somatosensory thalamus are very similar to those in primates. The density of GABAergic neurons in the somatosensory thalamus of the raccoon is less than that in the cat and monkey, but the relative distribution of GABAergic neurons in the different somatosensory nuclei is very similar to that in the cat and monkey. These results are discussed in relation to findings in other species and are related to the functions of lemniscal and nonlemniscal somatosensory pathways.

Animals↗
PubMed1997

Neurogenesis in the mammalian neostriatum and nucleus accumbens: parvalbumin-immunoreactive GABAergic interneurons.

We study the neurogenesis of a distinct subclass of rat striatum gamma-aminobutyric acid (GABA)ergic interneurons marked by the calcium-binding protein parvalbumin (PV). Timed pregnant rats are given an intraperitoneal injection of bromodeoxyuridine (BrdU), a marker of cell proliferation, on designated days between embryonic day (E) 11 and E22. Birthdate of PV neurons is determined in the adult neostriatum and nucleus accumbens by using a BrdU-PV double-labeling immunohistochemical technique. PV-immunoreactive interneurons of the neostriatum show maximum birthrates (>10% double-labeling) between E14-E17, whereas PV-immunoreactive interneurons of the nucleus accumbens show maximum double-labeling between E16-E19. In the neostriatum, caudal PV-immunoreactive neurons are born before those at rostral levels, and lateral PV-immunoreactive neurons become postmitotic before medial neurons. In the postcommissural striatum, ventral PV-immunoreactive neurons become postmitotic before dorsal neurons. In the precommissural striatum, ventral neurons are born before dorsal neurons laterally, but a dorsoventral gradient is seen medially. At corresponding coronal levels, PV-immunoreactive neurons of the nucleus accumbens are born shortly after PV neurons of the neostriatum. Analysis of BrdU labeling intensity in the nucleus accumbens shows that medium spiny projection neurons of the shell become postmitotic before neurons of the core. Similarly, PV-immunoreactive interneurons of the nucleus accumbens shell are born before PV interneurons of the core. Compared with cholinergic interneurons of the neostriatum, PV-immunoreactive interneurons are born later, but neurogenetic gradients are similar. The period of striatum PV interneuron genesis encompasses the period for somatostatin interneurons, although the latter neurons do not show neurogenetic gradients, possibly due to heterogeneous subtypes. Consideration of basal telencephalon neurogenesis suggests that subpopulations of striatum interneurons may share common neurogenetic features with phenotypically similar populations in the basal forebrain, with final morphology and connectivity depending on local cues provided by the host environment.

Animals↗
PubMed1998

CalbindinD28k- and parvalbumin-immunoreactive neurons form complementary sublaminae in the rat superior colliculus.

By using light microscopic immunocytochemistry and computer analysis, we have mapped the distributions of two calcium-binding proteins (CaBPs), calbindinD28k (CB) and parvalbumin (PV), in the rat superior colliculus (SC). The patterns of CaBP expression were complementary. A band of heavily labeled, medium-sized CB-immunoreactive cells (CB-cells) was centered in the optic layer (OL), whereas PV-immunoreactive cells (PV-cells) were found predominantly in the intermediate gray layer (IGL), where they were clustered within patches of PV-labeled fibers. The superficial gray layer (SGL) could be divided into two sublaminae. CB-cells were found mostly in the dorsal half of the SGL, whereas PV-cells were scattered throughout the ventral SGL and the dorsal OL. Most of the CaBP-immunoreactive cells in the SGL were small bipolar cells with vertically oriented dendrites; however, there were also some PV-cells with horizontally oriented dendrites. Quantitative analysis of the CaBP distributions reinforced our observations that these cells are distributed in complementary tiers that are not restricted to the traditional laminae. The size and shape of some of these tiers were determined from a three-dimensional reconstruction of serial sections. The complementarity of the CaBP-immunoreactive tiers was also confirmed by fluorescence microscopy of double-labeled sections, in which few if any double-labeled neurons were observed. Complementary tiers of CB-cells and PV-cells have been observed previously in the SC of the cat. The present results demonstrate them in another species and further suggest that there are functional sublaminae in the SC that can be distinguished by CaBP content.

Animals↗
PubMed1998

Calbindin-D 28 kD and parvalbumin in the horizontal cells of rat retina during development.

PURPOSE: Calbindin-D 28K (CaD) and parvalbumin (PV) are calcium-binding proteins thought to act as an intraneural calcium ion buffering system in the central nervous system. We previously reported that PV appears at birth in some cells in the outer portion of the nuclear layer of the retina that can differentiate into horizontal cells. CaD is also distributed in horizontal cells; however, it is not clear at which developmental stage CaD appears. METHODS: The development of horizontal cells and the distribution of CaD and PV was examined ultrastructurally and immunohistochemically in rat retinas from birth (P0) to postnatal day 50 (P50). RESULTS: Our ultrastructural data showed clear differentiation of horizontal cells from other retinal cells in the early postnatal days. These cells became nearly mature around P10 to P12. PV appeared in the outer nuclear layer at birth (P0) and, by P7, was observed in the ganglion cell layer, amacrine cells, and horizontal cells. CaD-immunoreactive cells, however, were not seen in any portions of the retina until P7. At P10, CaD-immunoreactivity was faintly observed in horizontal cells, and its immunoreactivity gradually increased in the horizontal cells from P10 to P15 when the eyes of the rats opened. CaD was not found in the ganglion cell layer or in amacrine cells at any period examined. CONCLUSION: In the horizontal cells, PV appeared when they were ultrastructurally distinguished from other retinal cells, while CaD appeared when they already had some structure for endocytosis and synaptic transmission, suggesting that PV and CaD may be good morphological and functional markers for horizontal cells, respectively.

Animals↗
PubMed1998

Complementary distributions of calbindin, parvalbumin and calretinin in the cerebellar vermis of the adult cat.

Immunocytochemistry was used to compare regional and cellular distribution of the calcium-binding proteins calbindin (CB), parvalbumin (PV) and calretinin (CR) in the cerebellar vermis of adult cats. CB and PV displayed similar patterns of distribution, mainly in Purkinje cells and their processes. Immunoreactive Purkinje cell axons were organised in bundles alternating with reaction-free strips, or raphes, of afferent fibres. In contrast, CR immunoreactivity was most apparent in unipolar brush neurons, and in mossy and climbing fibres. CR positive unipolar brush neurons were clustered and positive climbing fibres formed bands. Thus, CR was associated with afferent fibres and interneurons, and occurred in complementary structures to those demonstrated for CB and PV, mainly in efferent neurons and pathways.

Animals↗
PubMed1999

Precocious development of parvalbumin-like immunoreactive interneurons in the hippocampal formation and entorhinal cortex of the fetal cynomolgus monkey.

The calcium-binding protein parvalbumin (PV), a reliable marker of the hippocampal basket and chandelier cells, is first expressed on embryonic day 83 (E83), corresponding to midgestation of the macaque monkey, in restricted hippocampal groups of immature neurons (Berger and Alvarez [1996] J. Comp. Neurol. 366:674-699). In the present study, PV-like immunoreactivity (LIR) was used to follow the further development of this subclass of interneurons. Asynchronous area-specific developmental sequences were observed, predominating initially in the caudal half of the hippocampal formation and the laterocaudal division of the entorhinal cortex and occurring relatively simultaneously in the interconnected hippocampal and entorhinal subfields. Dendritic elongation of PV-like immunoreactive interneurons and perisomatic distribution of PV-like immunoreactive terminal boutons on their cellular targets were first observed in the subiculum around E127; then from E127 to E142 in CA3/CA2 and layers III-V of the entorhinal cortex and, to a lesser extent in CA1, the dentate hilus and deep granule cell layer; and finally from E156 to postnatal day 12 in the rest of the dentate gyrus, the presubiculum and parasubiculum, and layers III-II-I of the entorhinal cortex. These data provide the first indication that a population of basket cells, a major gamma-aminobutyric acid (GABA)ergic component of the hippocampal intrinsic inhibitory circuitry, reaches its cellular targets several weeks before birth in primates in contrast to rodents. The role of the prenatal PV expression in the hippocampal formation of nonhuman primates and whether it coincides with the onset of postsynaptic inhibitory potentials or is accompanied or preceded by a period of gamma-aminobutyric acid-mediated excitatory effects as in rat pups, are crucial questions. They underline the need to pursue direct investigations on primates to be able to legitimately extrapolate the data obtained in rodents.

Aging↗