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Topographic localization of calretinin, calbindin, VIP, substance P, CCK and metabotropic glutamate receptor immunoreactive neurons in the supramammillary and related areas of the rat.

A detailed description of the localization of neurons containing various neuropeptides in the supramammillary complex (SUM) is provided. Further, the neurochemical character of supramammillohippocampal and supramammilloseptal projecting neurons was investigated. The following experiments were performed: (a) immunocytochemistry for each of the eight different neuropeptides investigated, in animals pretreated or not with colchicine, and perfused in fixative containing or lacking acrolein; (b) a thorough mapping study of the localization of immunolabelled neurons at three rostrocaudal levels; (c) double-tracing retrograde labelling for two-directional neuronal projections combined with immunocytochemistry, to study neurochemical character of the projecting neurons. The observations are: (1) each type of immunolabelled elements, such as calretinin, calbindin, VIP, substance P, CCK and metabotropic glutamate receptor 1a immunopositive neurons has a characteristic localization; (2) no parvalbumin- and enkephalin-containing neurons are present in the SUM; and (3) a small population of calretinin-containing and a small number of calretinin-negative supramammillohippocampal neurons located in the lateral area also project to the medial septum-diagonal band region of the septal complex.

Animals↗

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↗

Parvalbumin and calbindin D-28k in the entopeduncular nucleus, subthalamic nucleus, and substantia nigra of the rat as revealed by double-immunohistochemical methods.

The cellular localization of calbindin D-28k (CB) and parvalbumin (PV) was analyzed by means of double-immunohistochemical techniques applied to single sections in the entopeduncular nucleus (EP), the subthalamic nucleus (STh), and the substantia nigra (SN) of the rat. In EP, PV-positive cells abounded centrally, where CB immunostaining was minimal. The medial and ventral sectors of EP were markedly enriched with CB neuropil but devoid of PV-positive cells. CB-positive neurons abounded particularly in the rostral pole of EP. In STh, PV-positive neurons and neuropil were concentrated in the lateral two thirds of this nucleus. Only a few PV-positive cells were detected in sectors of STh devoid of PV-positive neuropil. The STh was completely devoid of CB immunostaining. In the rostral two thirds of SN, PV-positive neurons were largely confined to the lateral half of the pars reticulata (SNR), and occurred more ventrally and medially in the caudal third. Intense CB-immunoreactive neuropil was found in medial and dorsal parts of rostral SNR, and CB-positive cells were observed in the SN pars compacta and the ventral tegmental area. PV and CB cells were also observed in the pars lateralis of SN. The markedly heterogeneous pattern of distribution of PV and CB in EP, STh, and SN suggests that these two calcium-binding proteins may label distinct functional domains in each of these three components of the rat basal ganglia.

Animals↗

Glutamatergic synaptic responses and long-term potentiation are impaired in the CA1 hippocampal area of calbindin D(28k)-deficient mice.

The contribution of the cytosolic calcium binding protein calbindin D(28K) (CaBP) to glutamatergic neurotransmission and synaptic plasticity was investigated in hippocampal CA1 area of wild-type and antisense transgenic CaBP-deficient mice, with the use of extracellular recordings in the ex vivo slice preparation. The amplitude of non-N-methyl-D-aspartate receptor (non-NMDAr)-mediated extracellular field excitatory postsynaptic potentials (fEPSPs) recorded in control medium was significantly greater in CaBP-deficient mice, whereas the afferent fiber volley was not affected. In contrast, the amplitude of NMDAr-mediated fEPSPs isolated in a magnesium-free medium after blockade of non-NMDAr and GABAergic receptors was significantly depressed in these animals. No alteration in the magnitude of paired-pulse facilitation was found, indicating that the presynaptic calcium mechanisms controlling glutamate release were not altered in CaBP-deficient mice. The magnitude and time course of the short-term potentiation (STP) of fEPSPs induced by a 30 Hz conditioning stimulation, which was blocked by the NMDAr antagonist 2-amino-5-phosphonovalerate acid (2-APV), was not impaired in the transgenic mice, whereas long-term potentiation (LTP) induced by a 100 Hz tetanus was not maintained. The long-term depression (LTD) induced by low-frequency stimulation (1 Hz, 15 min) in the presence of the GABA antagonist bicuculline was not altered. These results argue for a contribution of CaBP to the mechanisms responsible for the maintenance of long-term synaptic potentiation, at least in part by modulating the activation of NMDA receptors.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Calbindin immunoreactivity in the geniculo-extrastriate system of the macaque: implications for heterogeneity in the koniocellular pathway and recovery from cortical damage.

Although most projection neurons in the primate dorsal lateral geniculate nucleus (dLGN) target striate cortex (V1), a small number project instead to extrastriate visual areas and have been suggested to play a role in the preserved vision ("blindsight") that survives damage to V1. Moreover, the distribution of dLGN cells projecting to extrastriate bears a striking similarity to that of neurons that stain for calbindin D-28K (Cal), a calcium-binding protein involved in regulating neuronal excitability and considered a marker for the koniocellular or "K" pathway of geniculocortical processing. In these studies, we used double-labeling techniques to examine whether Cal content characterizes all or a subset of neurons making up the geniculo-extrastriate pathway in normal macaque monkeys. After injections of cholera toxin B-subunit into the prelunate gyrus, the proportion of retrogradely labeled neurons in the dLGN that were also immunoreactive for Cal varied from less than 40% to over 80%, indicating that only a subset of the geniculo-extrastriate projection falls within the K pathway as defined by Cal content. Analysis of the injected territories indicated that identity of the extrastriate cortical target may be systematically related to Cal content in the geniculo-extrastriate projection. To see whether the Cal-immunoreactive dLGN population might potentially play a role in preserved vision after V1 damage, we also examined the dLGN of a macaque that had sustained a lesion of V1 in infancy and survived until 4 years. In this animal, large, intensely Cal-immunoreactive neurons were found scattered throughout the otherwise degenerated dLGN zones and made up over 95% of the identifiable remaining neurons. The results support an emerging view that the macaque koniocellular system is highly heterogeneous in nature and also suggest that Cal content may be a critical feature of the pathway by which visual information reaches extrastriate cortex in the absence of V1.

Animals↗

Calbindin D28k and parvalbumin immunoreactivity in the rabbit superior colliculus: an anatomical study.

The expression pattern of two calcium binding proteins (CaBP), calbindin D28k (CB) and parvalbumin (PV), in the superior colliculus (SC) of the adult rabbit, as well as the morphology of the immunoreactive cells were examined. The study was performed on 12 rabbits. Coronal sections from postmortem SC were analyzed by light microscopy, and drawings of CaBP-labeled cells were obtained using a drawing tube. No previous information is available on either the CB/PV expression or the morphology of CB/PV positive cells in the SC of the adult rabbit. Therefore, in this study we show that CB neurons and neuropil form three main tiers: the first located within the stratum zonale (SZ) and the upper part of the stratum griseum superficiale (SGS), the second located within the stratum griseum intermedium (SGI), and the third, located within the medial and central areas of the stratum griseum profundum (SGP). In contrast to this layer labeling, almost no CB-positivity is found within the other collicular layers. On the other hand, the densest concentration of PV labeled cells and terminals is found within a single dense tier that spanned the ventral part of the startum griseum superficiale (SGS) and the dorsal part of the stratum opticum (SO). Anti-PV neurons are also scattered through the deeper layers below the dense tier. In contrast, almost no anti-PV labeled neurons or neuropil are found within the stratum zonale (SZ) and upper SGS. This distribution represents a new pattern of sublamination in the SC of this species. All the previously described cell types in other mammals are observed in the rabbit SC: marginal cells, horizontal cells, pyriform cells, narrow-field vertical cells, wide-field vertical cells, and stellate/multipolar cells. Detailed drawings of all these cellular types are represented to show their complete morphology. The results of this study indicate that both CB and PV are present in a variety of neurons, which present a number of homologies between mammals, but have a different location and/or distribution, according to the different species. These findings are thus relevant to better understand the organisation of the SC in mammals.

Animals↗

Differential expression of calbindin-D 28 kDa in rat incisor ameloblasts throughout enamel development.

Calbindin-D 28 kDa (CaBP 28 kDa), a vitamin D-dependent calcium-binding protein, has been associated with calcium handling by cells. We have investigated the expression of this protein in the rat incisor enamel organ, an epithelium interposed between a mineralizing matrix and connective tissue rich in blood vessels, by radioimmunoassay (RIA), Western blotting, and quantitative protein A-gold immunocytochemistry with antibodies to rat kidney CaBP 28 kDa. RIA of cytosolic extracts showed that enamel organs contained relatively high concentrations of CaBP 28 kDa (compared to kidney; see review by Christakos S., C. Gabrielides, and W.B. Rhoten 1989 Endocr. Rev., 10:3-25). Immunoblotting of proteins extracted from enamel organ strips revealed an intensely-stained band near 28 kDa throughout amelogenesis following ameloblast differentiation. Immunocytochemically, CaBP 28 kDa was localized exclusively within ameloblasts. The density of labelling increased from the presecretory stage to the secretory stage and fluctuated across the maturation stage in relation to ameloblast modulation. Ruffle-ended ameloblasts consistently showed the most intense immunoreaction. Gold particles were present throughout the cytoplasm and nuclei of ameloblasts but regions rich in rough endoplasmic reticulum or cell webs showed a higher immunolabelling. Some gold particles were also associated with the external face of the rough endoplasmic reticulum. Multivesicular bodies in maturation stage ameloblasts were occasionally immunoreactive. These data suggest that the intracellular concentration of CaBP 28 kDa is regulated throughout amelogenesis reflecting a stage-specific control of calcium homeostasis in ameloblasts.

Ameloblasts↗

Calbindin-immunoreactive neurones in the ovine rumen.

In small laboratory animals, such as guinea pigs, immunoreactivity for the calcium-binding protein calbindin (CALB) can be used to distinguish functionally different classes of myenteric neurones. The rumen of sheep is a highly specialized gastrointestinal region, and the control of its functions requires specific intrinsic innervation patterns. The aim of this study was to neurochemically identify and characterize CALB-positive myenteric neurones of the ovine rumen. Therefore, we performed quadruple immunohistochemistry against CALB, substance P (SP), vasoactive intestinal peptide (VIP), and nitric oxide synthase (NOS) using whole-mount preparations of the ruminal myenteric plexus. On average, 3 +/- 2 and 1 +/- 0.4 myenteric neurones/ganglion were CALB-immunoreactive in suckling lambs and adult sheep, respectively. These neurones had Dogiel type-I morphology. Most of them (89.2% +/- 8.7% and 71.7% +/-44.8% in suckling lambs and adult sheep, respectively) did not colocalize any of the other antigenes. Since it has been shown in previous studies that ruminal myenteric neurones are immunoreactive for either choline acetyltransferase (ChAT) or NOS, we defined neurones which were CALB-positive and NOS-negative as CALB/ChAT. The other CALB-positive neurones were encoded CALB/NOS/+/-VIP (10.3% +/- 9.3% and 26.7% +/- 46.2% in suckling lambs and adult sheep, respectively) or CALB/ChAT/SP (0.5% +/- 1.0% and 1.7% +/- 1.9% in suckling lambs and adult sheep, respectively). We used cryostat sections of the ruminal wall to analyze the projections of the CALB-positive neurones. CALB-immunoreactive somata were exclusively located within the myenteric plexus. CALB-immunoreactive nerve fibers were found primarily in the lamina propria of the ruminal papillae. We conclude that CALB-positive myenteric neurones within the ovine rumen project to the epithelium; however, their functional role remains to be investigated.

Animals↗

Distribution of calbindin D-28k in the entorhinal, perirhinal, and parahippocampal cortices of the macaque monkey.

We examined the distribution of calbindin D-28k-immunoreactive (CB-IR) neurons, fibers, and neuropil in the entorhinal (area 28), perirhinal (areas 35 and 36), and parahippocampal (areas TH and TF) cortices in the macaque monkey. Two main findings are reported. First, except for CB-IR neurogliaform cells that are only observed in the parahippocampal cortex, the morphology of CB-stained pyramidal and nonpyramidal cells were similar across the three cortical areas examined. Second, we find that the topography of CB staining differed between the three areas. The entorhinal cortex exhibits the most striking gradient of CB staining such that the most anterior and medial portions are most strongly labeled, whereas posterior and lateral areas exhibit only weak labeling. The labeling throughout the perirhinal and parahippocampal cortices is more homogeneous. Area 35 contains only lightly stained neuropil and few CB-IR cells. Area 36 and areas TH and TF of the parahippocampal cortex contain a moderate to high density of CB-IR cells and fibers throughout their full rostrocaudal extents, although each area exhibits unique laminar patterns of staining. In all areas examined, the highest density of CB-positive cells and fibers is observed in superficial layers with lower densities of CB-positive cells and fibers present in deep layers. These findings, taken together with our current understanding of the connections of these areas may have implications for understanding the circuit properties of the entorhinal, perirhinal, and parahippocampal cortices areas in both normal and disease states.

Animals↗

Structure of intraglomerular dendritic tufts of mitral cells and their contacts with olfactory nerve terminals and calbindin-immunoreactive type 2 periglomerular neurons.

Intraglomerular dendritic tufts of Golgi-impregnated and biotinylated dextran amine (BDA)-labeled mitral cells in the rat main olfactory bulb were analyzed in detail. In particular, the relationships of BDA-labeled tufts with olfactory nerve (ON) terminals and processes of calbindin D-28K-immunoreactive (CB-IR) cells were investigated with confocal laser-scanning light microscopic (CLSM) and electron microscopic (EM) analyses. CB-IR cells were type 2 periglomerular cells that restricted their processes in the ON-free (non-ON) zone of the glomerulus and received few synapses from ON terminals. The mitral tufts varied in complexity, but individual branches were rather simple, smooth processes that bore some branchlets and spines and extended more or less in a straight line or a gentle curve rather than winding tortuously within glomeruli as though they did not consider the compartmental organization, which consisted of ON and non-ON zones that interdigitated in a complex manner with one another. Conventional EM analysis revealed that both thin and thick, presumed proximal branches of mitral/tufted cell dendritic tufts received asymmetrical synapses from ON terminals. Correlated CLSM-EM analysis confirmed direct contacts between the BDA- and CB-labeled processes detected in the CLSM examinations, and synapses were recognized at some of those sites. Furthermore, ON terminals and CB-IR processes were distributed on both proximal and distal dendritic branches in a more or less mosaic pattern. These findings revealed that, on the mitral dendritic tufts, ON terminals and processes of type 2 periglomerular neurons were not clearly segregated proximodistally but, rather, were arranged in a mosaic pattern, which may be important in fine tuning the output from individual glomeruli.

Animals↗

Immunohistochemical localization of calcium-binding proteins, parvalbumin and calbindin-D 28k, in the adult and developing visual cortex of cats: a light and electron microscopic study.

In the cat primary visual cortex, we investigated with immunohistochemical techniques the developmental changes in the cellular and subcellular localization of the Ca2+-binding proteins parvalbumin (PV) and calbindin-D 28K (CBP), in order to determine whether there is a correlation between the expression of Ca2+-dependent processes and the time course of the critical period for use-dependent plasticity. On the 54th day of gestation and at 1 week postnatally, both calcium-binding proteins were present only in a subpopulation of neurons in layers V and VI. During subsequent maturation, the number of PV(+) and CBP(+) neurons increased significantly and labeled cells were detected in more superficial layers. Moreover, the homogeneous labeling of some CBP(+) neurons in layers IV to VI decreased and changed to a punctate pattern. In adult cats PV(+) neurons were evenly distributed throughout layers II to VI, whereas CBP(+) neurons were concentrated in layers II/III. Only a few immunoreactive cells had morphological features characteristic of pyramidal cells; the large majority were nonpyramidal. Electron microscopy confirmed the presence of PV- and CBP-reaction product within the perikarya, axons, and dendrites of labeled cells. It was associated preferentially with microtubules, postsynaptic densities, and intracellular membranes. Immunoreactive neurons received immunonegative asymmetric synapses on their dendritic shafts and made symmetric synaptic contacts with labeled and unlabeled somata and with unlabeled dendritic shafts. The large number and widespread distribution of immunoreactive neurons implies that PV and CBP play an important role in the regulation of calcium-dependent processes in the visual cortex. Furthermore, the developmental redistribution of PV and CBP points to changes in the organization of Ca2+-dependent processes during maturation.

Aging↗

Calcium-binding proteins, parvalbumin- and calbindin-D 28k-immunoreactive neurons in the rat spinal cord and dorsal root ganglia: a light and electron microscopic study.

The distribution of two calcium-binding proteins, parvalbumin (PV) and calbindin-D 28K (CaBP), was studied by the peroxidase-anti-peroxidase immunohistochemical method at the light and electron microscopic level in the rat spinal cord and dorsal root ganglia. The possible coexistence of these two proteins was also investigated. PV-positive neurons were revealed in all layers of the spinal cord, except lamina I, which was devoid of labelling. Most of the PV-positive cells were found in the inner layer of lamina II, lamina III, internal basilar nucleus, central gray region, and at the dorsomedial and ventromedial aspects of the lateral motor column in the ventral horn. Neuronal processes intensely stained for PV sharply delineated inner lamina II. With the electron microscope most of them appeared to be dendrites, but vesicle containing profiles were also found in a smaller number. CaBP-positive neurons appeared to be dispersed all over the spinal gray matter. The great majority of them were found in laminae I, II, IV; the central gray region; the intermediolateral nucleus; and in the ventral horn just medial to the lateral motor column. Laminae I and II were densely packed with CaBP-positive punctate profiles that proved to be dendrites and axons in the electron microscope. A portion of labelled neurons in lamina IV and on the ventromedial aspect of the lateral motor column in the ventral horn disclosed both PV- and CaBP-immunoreactivity. All of the funiculi of the spinal white matter contained a large number of fibres immunopositive for both PV and CaBP. The highest density of CaBP-positive fibres was found in the dorsolateral funiculus, which was also densely packed with PV-positive fibres. PV-positive fibres were even more numerous in the dorsal part of the dorsal funiculus. The territory of the gracile funiculus in the brachial cord and that of the pyramidal tract in its whole extent were devoid of labelled fibres. In the thoracic cord, the dorsal nucleus of Clarke received a large number of PV-positive fibres. Dorsal root ganglia displayed both PV- and CaBP-immunopositivity. The cell diameter distribution histogram of PV-positive neurons disclosed two peaks--one at 35 microns and the other at 50 microns. CaBP-positive cells in the dorsal root ganglia corresponded to subgroups of small and large neurons with mean diameters of 25 microns and 45 microns, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Localization of two calcium binding proteins, calbindin (28 kD) and parvalbumin (12 kD), in the vertebrate retina.

We used immunocytochemistry to locate two calcium binding proteins, calbindin (CaB) and parvalbumin (PV), in the retina of goldfish, frog, chick, rat, guinea pig, dog, and man. The location of CaB depended on the type of dominant photoreceptor cells in birds and mammals. In cone-dominant retinas such as those of the chick, CaB-like immunoreactivity was found in the cones, cone bipolars, and ganglion cells. Amacrine cells 5-12 microns across were also labeled. In rod-dominant retinas, such as those of the rat, guinea pig, and dog, horizontal cells, small amacrine cells (about 6 microns across), and cells in the ganglion cell layer were labeled. In the human retina, which has both cones and rods in abundance, cones, cone bipolars, ganglion cells, horizontal cells, and small and large amacrine cells were labeled. In the frog and goldfish, the level of CaB-like immunoreactivity was low. In the frog, a few cones, amacrine cells, and cells in the ganglion cell layer were labeled. No immunoreactive structures were seen in the goldfish retina. PV-like immunoreactivity was found in chicks, rats, and dogs. No such immunoreactive structures were seen in the other species. In the chick, only amacrine cells were labeled. In the rat, amacrine cells and several displaced amacrine cells were labeled. In the dog, in addition to amacrine cells and displaced amacrine cells, horizontal cells were strongly labeled. Thus, PV-like immunoreactivity was found in those elements relating to the modulation of the main pathway of the visual transmission system.

Animals↗

The calcium binding protein calbindin-D 28K reveals subpopulations of projection and interneurons in the cat superior colliculus.

The calcium binding protein calbindin-D 28K (CaBP) has been localized in the cat superior colliculus (SC). Four important features of SC organization have been revealed by using CaBP immunocytochemistry. 1) CaBP neurons formed three laminar tiers in SC, one within the upper one half of the superficial gray layer (SGL), the second bridging the deep optic (OL) and intermediate gray layers (IGL), and the third within the deep gray layer (DGL). 2) CaBP labeled several classes of interneuron in SC. In the upper CaBP tier, the labeled neurons were all small, but they varied in morphology and included horizontal, pyriform, and stellate neurons. A unique class of interneuron was labeled by anti-CaBP in the OL-IGL tier. This cell was stellate-like with highly varicose dendrites and broad dendritic trees. Other labeled neurons in the intermediate and deep tiers included nonvaricose stellate neurons and rare large neurons in the DGL. 3) A few anti-CaBP neurons were projection neurons. Virtually no CaBP neurons were retrogradely labeled after injections of HRP into the predorsal bundle and dorsolateral midbrain tegmentum or into the lateral posterior nucleus. However, 2.4% of anti-CaBP neurons were retrogradely labeled after HRP injections into the dorsal and ventral lateral geniculate nuclei. These represented 14.7% of all neurons projecting to the LGN complex. 4) A small percentage of CaBP neurons co-localized GABA. A two-chromagen double-labeling technique showed that about 4.0% of labeled neurons were labeled by both antibodies. In summary, antibodies to CaBP densely labeled subpopulations of neurons in the cat SC, most of which were interneurons, some of which projected to the LGN, and a few of which co-localized GABA.

Animals↗

Development of the calcium-binding protein parvalbumin and calbindin in monkey striate cortex.

The development of immunoreactivity for the calcium-binding proteins parvalbumin (PV) and calbindin-D28K (Cal) was studied in Macaca nemestrina striate cortex from fetal (F) 60 days to postnatal (P) 5 + years. We correlated changes in PV and Cal staining patterns with the well-documented developmental sequence for primate striate cortex neuron generation and maturation, synaptogenesis, and thalamocortical axon interactions in an attempt to deduce a functional role for these proteins. Our major findings is that Cal and PV have diametrically opposed developmental patterns except in layer 1. At F60 days both are present only in neurons of layer 1 and the number of labeled cell bodies and processes increases up to F125 days. Almost all Cal+ and PV+ cells in layer 1 disappear by P12 weeks. Cal is present by F113 days in pyramidal and stellate neurons, particularly layers 4-6. The numbers and staining density of cells in layers 2-6 increases up to birth and then both decline by P9-12 weeks. Supragranular layers show a second increase in Cal labeling from P20-36 weeks, and then there is a slow decline to the adult pattern which is reached by P1-2 years. Cell bodies in layers 4A, 4C alpha, and deep 4C beta are heavily Cal+ during pre- and early post-natal periods, but upper 4C beta remains unlabeled. PV is not seen until F155-162 days in layers 2-6. Large stellate and a few pyramidal cells appear first in layers 5/6 and 4C alpha, but PV+ stellate neurons are found in all layers except 4C beta by P6 weeks. Layer 4C beta contains a few PV+ cell bodies at P3 weeks, and light neuropile staining at P6 weeks, but then PV labeling rapidly increases so that by P12 weeks the density of 4C beta exceeds that of 4C alpha. Striate cortex has an adult pattern of cell number and neuropile density by P20 weeks. These developmental patterns suggest that the highest density of Cal cell body staining does not correlate with synaptogenesis, or the postnatal critical period of visually driven, binocular interactions. Rather Cal appears when lateral geniculate axons arrive in cortex, persists over the entire span of thalamocortical interactions, and disappears during the decline of cortical plasticity. The appearance of PV is highly correlated with the onset of complex visually driven activity at birth, while both the number of PV+ cell bodies and the density of PV+ neuropile reach adult levels coincident with the completion of thalamocortical connections.

Animals↗

Parvalbumin- and calbindin D28k-immunoreactive neurons in the hippocampal formation of the macaque monkey.

Calcium-binding proteins calbindin D28k (CaBP) and parvalbumin (PV) were localized in neurons of the monkey hippocampal formation. CaBP immunoreactivity is present in all granule cells and in a large proportion of CA1 and CA2 pyramidal neurons, as well as in a distinct population of local circuit neurons. In the dentate gyrus, CaBP-immunoreactive nongranule cells are present in the molecular layer and in the hilar region, but they do not include the pyramidal basket cells at the hilar border. In the Ammon's horn, CaBP-positive, nonpyramidal neurons are more frequent in the CA3 area than in any other parts of the hippocampal formation. They are concentrated in the strata oriens and pyramidale of areas CA1-3, whereas only a few small neurons were found in the strata lucidum and radiatum of CA3 and in the stratum moleculare of the CA1 area. PV is exclusively present in local circuit neurons both in the dentate gyrus and in Ammon's horn. In the dentate gyrus the presumed basket cells at the hilar border exhibit PV immunoreactivity. In the hilar region and molecular layer only a relatively small number of cells are immunoreactive for PV. Most of these PV-positive cell bodies are located in the inner half of the molecular layer, with occasional horizontal cells at the hippocampal fissure. In Ammon's horn, strata oriens and pyramidale of areas CA1-3 contain a large number of PV-positive cells. There are no PV-immunoreactive cells in the strata lucidum, radiatum, or lacunosum moleculare. The CaBP- and PV-containing neurons form different subpopulations of cells in the monkey hippocampal formation. With the exception of a basket cell type in the monkey dentate gyrus, the CaBP- and PV-positive cell types were found to be remarkably similar in rodents and primates.

Animals↗

The calcium binding proteins parvalbumin and calbindin-D 28K form complementary patterns in the cat superior colliculus.

Parvalbumin (PV) and calbindin-D 28K (CaBP) are calcium binding proteins involved in calcium regulation in the brain. In some regions they coexist in the same neuron, while in other regions they are found in different cell types. We have studied the distribution and morphology of PV labeled neurons in the cat superior colliculus (SC) with antibody immunocytochemistry and compared this labeling to that of CaBP. PV neurons were concentrated in a dense tier within the deep superficial gray and upper optic layers. Scattered PV neurons also were found within the deep layers of SC. By contrast, CaBP neurons were concentrated in three tiers: one within the zonal and upper superficial gray layers, a second within the deep optic and upper intermediate gray layers (IGL), and a third within the deep gray layer. The distribution of PV neurons is thus complementary to that of CaBP neurons, with the CaBP cell tiers bordering the dense tier of PV neurons. PV neurons varied in size and morphology. The average diameter of labeled cells was 20 microns, almost twice the size of CaBP neurons. The cells were predominantly round, vertical fusiform, or stellate, and included the very large neurons found scattered in the IGL. Horseradish peroxidase injections into the lateral geniculate nucleus, the lateral posterior nucleus, the opposite superior colliculus, the dorsal lateral pontine gray nucleus, and two descending pathways--the crossed predorsal bundle and the tecto-ponto-bulbar tracts--each labeled SC neurons that were also labeled by PV. A large percentage (84%) of projection neurons contained PV. This result also differs from CaBP neurons in SC, most of which are interneurons. Two antigen double-label experiments did not produce any cells that contained both PV and CaBP. The two calcium binding proteins thus reveal a unique sublaminar organization in SC that consists of alternating small cell interneuron groups and large cell projection neuron groups.

Animals↗

Parvalbumin and calbindin immunocytochemistry reveal functionally distinct cell groups and vibrissa-related patterns in the trigeminal brainstem complex of the adult rat.

Immunocytochemistry for calbindin (CA) and parvalbumin (PA) was combined with retrograde tracing from the thalamus, superior colliculus (SC), and cerebellum to define the ascending projections of neurons in the rat's trigeminal (V) brainstem complex that express immunoreactivity for these calcium binding proteins. Many PA-immunoreactive neurons were observed in trigeminal nucleus principalis (PrV). Many of these cells projected to thalamus and a few sent axons to SC. In ventral PrV, PA-immunoreactive neurons were arranged in a vibrissa-related pattern. A very small number of large CA-immunoreactive neurons were observed in dorsomedial PrV. None of these cells were labeled by our tracer deposits. Small neurons in V subnucleus oralis (SpO) were also immunoreactive for PA, but none were retrogradely labeled. A small percentage of the large neurons in SpO were CA-immunoreactive; many of these were retrogradely labeled by tracer injections in the thalamus and/or SC. In V subnucleus interpolaris (SpI), many small to medium sized cells were PA-positive and they were arrayed in a vibrissae-like pattern. None of these neurons were retrogradely labeled from any of the above-listed targets, but many were retrogradely labeled by tracer injections into ipsilateral PrV. SpI also contained many large CA-immunoreactive cells. Many of these projected to the thalamus and/or SC and some were also retrogradely labeled by tracer injections into ipsilateral PrV. In V subnucleus caudalis (SpC), very dark PA-immunoreactive neurons were located in the inner part of lamina II and less often in laminae I. Lightly labeled cells were located in the magnocellular laminae and formed vibrissa-related aggregates. None of these neurons were retrogradely labeled by our tracer injections. CA-immunoreactive cells were located throughout the depth of lamina II in SpC and smaller numbers were also visible in lamina I and layers III-V. A small percentage of the CA-positive cells in lamina I and in the magnocellular layers were retrogradely labeled from the thalamus. These data indicate that PA and CA antisera identify two cell populations in whisker-related regions of the V brainstem complex and that PA cells are somatotopically patterned in PrV, SpI, and SpC. These markers also distinguish two cell groups in superficial laminae of the medullary dorsal horn.

Afferent Pathways↗