PubMed Health⌕ Search

Biomedical subjects

D M Jacobowitz

Publications and source records attributed to D M Jacobowitz.

At least 55 records · Page 3Linked to original sources
PubMed1995

Corticosterone effects on rat calretinin mRNA in discrete brain nuclei and the testes.

Calretinin is an EF-hand calcium binding protein found predominantly in discrete sets of neurons in the central system, and in the sex hormone producing cells of the gonads. Calretinin mRNA levels were measured in discrete brain areas from vehicle and corticosterone treated rats (subcutaneous injections of 0, 0.1, 1, or 10 mg, 7 days) using a micropunch ribonuclease protection assay. Treatment with high dose corticosterone (10 mg) caused a 93% decrease in calretinin mRNA levels in the hypothalamic paraventricular nucleus compared to controls. Two other brain regions, the medial amygdaloid nucleus and the nucleus reuniens, demonstrated an approximately 40% decrease in calretinin mRNA following high dose corticosterone. In separate experiments, adrenalectomy and diurnal corticosterone variations had no effect on calretinin mRNA in the brain areas examined. In the testes, corticosterone treatment decreased calretinin protein in a dose dependent fashion (to 81%, 68%, and 39% of controls at doses of 10, 1, and 0.1 mg/day, respectively). Low dose corticosterone treatments decreased testicular but not neuronal calretinin mRNA, whereas high dose corticosterone reduced calretinin mRNA in testes and several discrete brain areas. This suggests that corticosterone's effects on brain calretinin may be due to its pathological effects, e.g. energy depletion of brain cells or interference with the normal support functions of glia.

Amygdala↗
PubMed1995

Detailed mapping of CGRP mRNA expression in the rat central nervous system: comparison with previous immunocytochemical findings.

The localization of CGRP mRNA in neurons of the rat brain and spinal cord was assessed by in situ hybridization histochemistry (ISH) using a radiolabeled synthetic 57-mer oligodeoxynucleotide probe complementary to the rat prepro CGRP mRNA. Results were compared with previously published findings of CGRP-immunoreactive (CGRP-IR) cell bodies revealed by an indirect immunofluorescence technique. The highest numbers of CGRP mRNA expressing neurons as well as the greatest intensity of staining were found in the lateral hypothalamic area, the parabrachial nuclei, and among the cranial motor nuclei, especially in the nuclei of the 7th and 12th nerve and the ambiguus nucleus, which is generally in good agreement with findings assessed by immunocytochemistry (ICH). However, some mismatches between the localization of the peptide by ICH and the localization of the CGRP mRNA were also observed. Thus, ISH was not able to confirm CGRP-IR in cells of the amygdaloid complex and parts of the medial hypothalamus, the central gray, and the inferior colliculus, but ISH revealed considerably more CGRP mRNA expressing cells in the lateral hypothalamic area, arcuate nucleus, posterior and peripeduncular thalamic nuclei, and all cranial motor nuclei than CGRP-IR containing cells found by ICH. Moreover, ISH also revealed CGRP mRNA synthesis in the nucleus of the lateral olfactory tract and in the perihypoglossal nuclei that were devoid of CGRP-IR. The reasons for the observed mismatches still remain to be elucidated; however, intracerebroventricular colchicine pretreatment used to increase immunocytochemical signals also might have induced or suppressed gene expression in certain brain regions in an unpredictable matter. On the other hand, detection of only the mRNA in a certain region does not necessarily mean that also the active peptide is synthesized there.

Animals↗
PubMed1995

Alteration in levels of expression of brain calbindin D-28k and calretinin mRNA in genetically epilepsy-prone rats.

Variations in the concentration of free calcium in neurons is believed to play a major role in regulating neuronal excitability. Because calcium-binding proteins such as calbindin D-28k and calretinin help to regulate intracellular calcium, we investigated the possibility that the expression of these proteins may be affected in genetically epilepsy-prone rats (GEPRs). The mRNA levels of both proteins were compared across several brain regions using in situ hybridization histochemistry and Northern blot analysis with semiquantitation by optical density measures in autoradiograms from two GEPR strains that differ in the severity of audiogenic seizures (GEPR9 and GEPR3) and from Sprague-Dawley rats. Results revealed a lower level of expression in calbindin D-28k mRNA in the in the caudate putamen-accumbens nuclei in GEPR3 (-30%) and GEPR9 (-60%) relative to controls. The calbindin D-28k mRNA level was also lower in the reuniens nucleus of the thalamus (-41% in GEPR3; -34% in GEPR9). The calretinin mRNA level was lower in the substantia nigra compacta of both GEPR rat strains (-31% in GEPR3 and -34% in GEPR9 relative to controls). No changes in mRNA were detected in other brain regions expressing calbindin D-28k or calretinin mRNA. These results indicate that the expression of these related calcium-binding proteins is altered in the GEPRs before the induction of seizures. This initial defect could alter either the calcium-buffering capacity or regulation of calcium-mediated processes by these proteins and thus play a role in the molecular cascade of events inducing the genetic susceptibility to, and the generalization of, seizures in these rat strains.

Animals↗
PubMed1995

Comparative immunohistochemical distribution of amylin-like and calcitonin gene related peptide like immunoreactivity in the rat central nervous system.

Using the indirect immunofluorescence method with a polyclonal antiserum raised in rabbits and directed against amylin (AMY), we have investigated the distribution of AMY-like immunoreactivity (-ir) throughout the central nervous system of the rat. The widespread distribution of AMY-ir was much more abundant than that previously reported for calcitonin gene related peptide (CGRP) immunoreactivity. In most brain areas there was no overlap between AMY- and CGRP-ir cell body groupings, with the exception of the motor nuclei of the hindbrain and spinal cord, which were found to contain large numbers of AMY- and CGRP-immunoreactive cell bodies. Areas with a moderate to dense appearance of AMY-ir were the rhinencephalon, the nucleus of the diagonal band, the magnocellular, dorso- and ventro-medial and mammillary nuclei of the hypothalamus, the habenula, the compact part of the substantia nigra, the ruber and pontine nuclei, and the inferior olive and the cerebellar nuclei. The widespread immunohistochemical distribution of AMY-ir in the rat brain is in partial agreement with the distribution of AMY-binding sites.

Amyloid↗
PubMed1995

Chemically defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb.

Chemically-defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb were revealed immunocytochemically using antibodies against gamma-amino butyric acid (GABA), tyrosine hydroxylase (TH), methionin-enkephalin-Arg6-Gly7-Leu8 (ENK), calretinin (CR), calbindin-D28K (calbindin) and thyrotropin-releasing hormone (TRH). GABA-like immunoreactive (GABA-LIR) neurons and CR immunoreactive (CR-IR) neurons were most numerous; they were about 1.5-3 times more numerous than calbindin immunoreactive (calbindin-IR), TH immunoreactive (TH-IR), ENK-like immunoreactive (ENK-LIR) and THR-like immunoreactive (TRH-LIR) neurons. We identified at least three distinct chemically-defined neuron groups, GABA-LIR neurons, CR containing neurons and calbindin containing neurons, since these three neuron groups were almost separate from one another. On the other hand, TH-IR and ENK-LIR neurons were nearly included in and thus considered to be subpopulations of GABA-LIR and CR-IR neurons, respectively, for about 80% of these two neuron groups contained GABA-L and CR immunoreactivities, respectively. TRH-LIR neurons appeared to be divided into two subpopulations, one containing the GABA-L immunoreactivity and the other containing the CR immunoreactivity. Thus in the glomerular layer of the rat olfactory bulb, GABA-LIR, CR-IR and calbindin-IR cells could be considered to be three distinct chemically-defined neuron groups, whereas TH-IR, TRH-LIR and ENK-LIR neurons were regarded as their subpopulations. Furthermore, some neurons groups, whereas TH-IR, TRH-LIR and ENK-LIR neurons were regarded as their subpopulations. Furthermore, some neurons are supposed to contain three substances (e.g. GABA + TH + TRH, GABA + TRH + EnK, CR + TRH + ENK, GABA + TRH + CR) or a few might even contain four substances (e.g. GABA + TRH + CR + ENK). Preliminary quantitative analysis using the optical disector method showed percentages of these three main neuron groups to total cells in the glomerular layer; that is, neuron groups containing GABA, CR and calbindin were about 20%, 20% and 10%, respectively.

Animals↗
PubMed1994

Calretinin is expressed in the Leydig cells of rat testis.

Calretinin, a highly evolutionarily conserved E-F hand calcium binding protein, is expressed predominantly in neurons, with a few exceptions. The function of calretinin is not known. We demonstrate the expression of calretinin mRNA and protein in rat testes. Immunocytochemistry and in situ hybridization reveal that calretinin expression in testis is localized to the interstitial Leydig cells. Western blot and ribonuclease protection analyses show that calretinin protein and mRNA in testis is the same as that expressed in brain. It is suggested that calretinin may play a role in the production of testosterone.

Animals↗
PubMed1994

Parvalbumin, calretinin and carbonic anhydrase in the trigeminal and spinal primary neurons of the rat.

The cell-body size of parvalbumin-immunoreactive (-ir) primary neurons was measured in the trigeminal (TG) and lumber dorsal root ganglia (DRG). In the DRG, parvalbumin-ir was mostly detected in large cells (94% in the range of 600-2800 microns2). Parvalbumin-ir TG cells were smaller than similar DRG cells and yet parvalbumin-ir TG cells of < 400 microns2 (2.86%) were rare. Trichrome stains for parvalbumin, calretinin (CR) and carbonic anhydrase (CA), and for parvalbumin, calcitonin gene-related peptide (CGRP) and CA were performed to estimate possible overlap of these substances. Virtually all parvalbumin-ir DRG cells contained CA activity while a small subpopulation (28.5%) of CR-ir DRG cells lacked CA activity. All the CR-ir DRG cells that exhibited CA were also ir for parvalbumin. 31.1% of parvalbumin-ir DRG cells exhibited CR-ir while 71.5% of CR-ir DRG cells showed parvalbumin-ir. All the CR-ir DRG cells of < 400 microns2 lacked CA activity and parvalbumin-ir while all those of > 800 microns2 exhibited both activities. Approximately 30% of CR-ir DRG cells in the size range of 400-800 microns2 co-expressed CA. DRG cells co-expressing parvalbumin and CGRP were rare (approximately 1%). As was the case for the DRG, most of parvalbumin-ir TG cells exhibited CA activity (89.24%) and lacked CGRP-ir (96.6%). CR-ir TG cells were also subdivided into two groups; one with and the other without co-expression of CA. Unlike in the DRG, however, co-expression of parvalbumin and CR could never be detected in the TG.

Animals↗
PubMed1994

Neural parvalbumin and calretinin in the tooth pulp.

Parvalbumin- and calretinin-immunoreactivities (CR-irs) were examined in the molar tooth pulp of the rat using immunohistochemical methods. CR-ir fibers were further classified based on the tachykinin-ir revealed by a double immunofluorescence method. The rat root pulp contained three types of nerve fibers; parvalbumin-ir smooth fibers, CR-ir (TK-negative) smooth fibers and CR-ir (TK-ir) varicose fibers. These fibers projected toward the roof of the pulp chamber and pulp horn without marked ramification. In the subodontoblastic layer at the roof of the pulp chamber and pulp horn, parvalbumin-ir smooth fibers repeatedly ramified and extended varicose terminals into the odontoblastic layer. CR-ir (TK-negative) smooth fibers reached the subodontoblastic layer without marked ramification and gave rise to varicose terminals that appeared to terminate within the subodontoblastic layer. On the other hand, CR-ir (TK-ir) varicose fibers proceeded to the subodontoblastic layer at the roof of the pulp chamber and pulp horn, where they ramified and penetrated the odontoblastic layer. The present study indicates that the rat tooth pulp contains myelinated parvalbumin-ir and CR-ir (TK-negative) fibers, and unmyelinated CR-ir (TK-ir) fibers, and that they project varicose terminals to the subodontoblastic and odontoblastic layers. The central projection sites of these sensory fibers have yet to be revealed.

Animals↗
PubMed1994

Local circuit neurons immunoreactive for calretinin, calbindin D-28k or parvalbumin in monkey prefrontal cortex: distribution and morphology.

In the cerebral cortex, local circuit neurons provide critical inhibitory control over the activity of pyramidal neurons, the major class of excitatory efferent cortical cells. The calcium-binding proteins, calretinin, calbindin, and parvalbumin, are expressed in a variety of cortical local circuit neurons. However, in the primate prefrontal cortex, relatively little is known, especially with regard to calretinin, about the specific classes or distribution of local circuit neurons that contain these calcium-binding proteins. In this study, we used immunohistochemical techniques to characterize and compare the morphological features and distribution in macaque monkey prefrontal cortex of local circuit neurons that contain each of these calcium-binding proteins. On the basis of the axonal features of the labeled neurons, and correlations with previous Golgi studies, calretinin appeared to be present in double-bouquet neurons, calbindin in neurogliaform neurons and Martinotti cells, and parvalbumin in chandelier and wide arbor (basket) neurons. Calretinin was also found in other cell populations, such as a distinctive group of large neurons in the infragranular layers, but it was not possible to assign these neurons to a known cell class. In addition, although the animals studied were adults, immunoreactivity for both calretinin and calbindin was found in Cajal-Retzius neurons of layer I. Dual labeling studies confirmed that with the exception of the Cajal-Retzius neurons, each calcium-binding protein was expressed in separate populations of prefrontal cortical neurons. Comparisons of the laminar distributions of the labeled neurons also indicated that these calcium-binding proteins were segregated into discrete neuronal populations. Calretinin-positive neurons were present in greatest density in deep layer I and layer II, calbindin-immunoreactive cells were most dense in layers II-superficial III, and parvalbumin-containing neurons were present in greatest density in the middle cortical layers. In addition, the relative density of calretinin-labeled neurons was approximately twice that of the calbindin- and parvalbumin-positive neurons. However, within each group of labeled neurons, their laminar distribution and relative density did not differ substantially across regions of the prefrontal cortex. These findings demonstrate that calretinin, calbindin, and parvalbumin are markers of separate populations of local circuit neurons in monkey prefrontal cortex, and that they may be useful tools in unraveling the intrinsic inhibitory circuitry of the primate prefrontal cortex in but normal and disease states.

Animals↗
PubMed1994

Expression and rapid purification of recombinant rat calretinin: similarity to native rat calretinin.

Rat calretinin coding region was subcloned into a prokaryotic expression vector (pGEX). The glutathione-S-transferase:calretinin fusion protein produced in Escherichia coli was purified on a glutathione-Sepharose affinity column. Recombinant rat calretinin was cleaved on the column by thrombin, eluted, and purified to homogeneity using DEAE-cellulose chromatography. Recombinant and native rat calretinin performed the same on DEAE columns, denaturing polyacrylamide gel electrophoresis (SDS-PAGE), Western blots, and 45Ca overlay on nitrocellulose blots. The recombinant calretinin migrated similarly to the more basic (pI 5.3) of two forms of native calretinin demonstrated by two-dimensional SDS-PAGE. Calcium binding equilibria revealed identical apparent binding affinity and capacity. Difference(s) between native and recombinant did not affect the binding of calcium to calretinin or antibody recognition. Thus recombinant calretinin may be useful in the elucidation of possible cellular targets of native calretinin.

Animals↗
PubMed1994

The unipolar brush cells of the rat cerebellar cortex and cochlear nucleus are calretinin-positive: a study by light and electron microscopic immunocytochemistry.

Cell class-specific markers are powerful tools for the study of individual neuronal populations. The peculiar unipolar brush cells of the mammalian cerebellar cortex have only recently been definitively identified by means of the Golgi method, and we have explored markers of cerebellar neurons with the purpose of facilitating the analysis of this new cell population and, especially, its distribution and ultrastructural features. By light microscopic immunocytochemistry, we demonstrate that, in the rat, the unipolar brush cells are the cortical neurons that are most densely immunostained with antiserum to calretinin, a recently discovered calcium-binding protein. The unipolar brush cells are highly concentrated in the flocculo-nodular lobe, the ventral uvula and the ventral paraflocculus, occur at relatively high density in the lingula, at moderate-to-low density in other folia of the vermis and in the narrow intermediate cortex, and at low to very low density, with the exception of a few hot spots, in the lateral regions of the cerebellar hemispheres and in the dorsal paraflocculus. Unipolar brush cells are also found in the cochlear nucleus. In addition to the unipolar brush cells, calretinin antibody distinctly stains certain mossy fibers, and weakly to moderately stains other cerebellar elements, such as granule neurons and climbing fibers. In the lobules containing high densities of unipolar brush cells, the granule cell bodies and the parallel fibers are much less immunoreactive, and there are many more densely immunostained mossy fibers than in the lobules, where these cells are rare, which suggests some relationships between these elements. In the cerebellar nuclei, small neurons are densely immunostained, while large neurons are immunonegative. The unipolar brush cells reside nearly exclusively in the granular layer. They are small neurons, intermediate in size between granule cells and Golgi cells, and their features are remarkably similar across all lobules. They usually have a single, relatively thick dendrite of varying length that terminates in a brush-like tip consisting of several short branchlets. Utilizing a pre-embedding protocol, we have identified unipolar brush cells with the electron microscope. The cytoplasm of these cells is partially obscured by the electron dense product of calretinin immunoreaction in all regions of the soma and processes. The cells are often covered with non-synaptic appendages and contain a peculiar cytoplasmic inclusion consisting of ringlet subunits. Other characteristic components are numerous neurofilaments, mitochondria and large, dense-core vesicles. Individual brushes enter one or two glomeruli, where the dendritic branchlets establish an unusually extensive synapse with mossy fiber rosettes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Mapping of the colocalization of calretinin and tyrosine hydroxylase in the rat substantia nigra and ventral tegmental area.

The distribution of calretinin (CR), a calcium binding protein, was compared with that of tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of dopamine, throughout the rostrocaudal extent of the rat substantia nigra (SN) and ventral tegmental area (VTA). After mapping the cells using double-labelling immunofluorescence, it was possible to distinguish three distinct cell types: cells immunoreactive for CR only, cells immunoreactive for TH only, and cells in which the two proteins were colocalized (CR + TH). Colocalized cells in rat brain sections comprised approximately 40-55% of the fluorescent labelled cells in the SN compacta, 30-40% in the VTA, and 55-80% in the SN lateralis. Colocalized cells in the SN reticulata were infrequent except in the more caudal sections where a majority of the TH-immunoreactive cells also contained CR. The percentage of CR cells that contained TH was approximately 80% in the SN compacta and averaged 65% in the VTA. Overall, the percentage of TH-immunoreactive cells which also contained CR was approximately 50% in the SN compacta and 45% in the VTA. These data reveal a significant degree of colocalization of CR in dopamine-producing cells of the SN and VTA and suggest the need for studies concerning the fate of these individual cell types following experimental manipulations.

Animals↗
PubMed1994

Heterogeneity in calbindin-D28k expression in oxytocin-containing magnocellular neurons of the rat hypothalamus.

We have used a double-labeling immunofluorescence method to examine whether oxytocin-containing magnocellular neurons possess a calcium-binding protein, calbindin-D28k, in the hypothalamus of the rat. In the supraoptic nucleus, most oxytocin-immunoreactive cells were also stained for calbindin-D28k. However, in the magnocellular part of the paraventricular nucleus nearly all oxytocin-labeled cells were devoid of calbindin-D28k. In the anterior commissural nucleus, approximately one-third of oxytocin-stained cells were also calbindin-D28k-immunoreactive, but the other cells were negative for calbindin-D28k. This study indicates that there may be distinct chemical features between oxytocin-containing magnocellular neurons of the supraoptic nucleus compared to those of the paraventricular nucleus.

Animals↗
PubMed1994

Dietary calcium deficiency causes a reduction in calretinin mRNA in the substantia nigra compacta-ventral tegmental area of rat brain.

Dietary calcium deprivation (3 weeks) affected neuronal gene expression of calretinin. Calcium deprived rats exhibited calcium appetite, weight loss, and a 28% decrease in calretinin mRNA in the substantia nigra compacta-ventral tegmental area, compared to controls. No changes were detected in 2 other mRNAs (tyrosine hydroxylase, beta-actin) and 5 other brain regions examined. This region-specific reduction of calretinin mRNA may relate to the altered physiology or behavior.

Actins↗
PubMed1994

Distribution of calretinin, calbindin-D28k, and parvalbumin in the rat thalamus.

The localization of three calcium-binding proteins, calretinin, calbindin-D28k, and parvalbumin, in the rat thalamus was immunohistochemically examined. a) Some thalamic regions revealed cells almost exclusively containing one of the calcium-binding proteins. For example, almost only calretinin-stained cells were found in the central medial and paraventricular nuclei. Calbindin-D28k-stained cells were mostly found in the centrolateral, interanteromedial, anteromedial, and posterior nuclei. Only parvalbumin-positive cells were found in the central part of the reticular nucleus. b) Other regions expressed overlap between the distributions of two cell components composed of different calcium-binding proteins. For example, both calretinin-stained cells and calbindin-D28k-labeled cells were found in the lateroposterior, intermediodorsal, rhomboid, and reuniens nuclei. c) Other regions showed no cells stained for any of the calcium-binding proteins. For example, generally no calcium-binding protein was detected in neurons of the anterodorsal, anteroventral, ventrolateral, ventral posterolateral, ventral posteromedial, or gelatinosus nuclei, or of the central part of the mediodorsal nucleus. These three proteins serve as useful marker for localizing subpopulations of neurons within the thalamus.

Animals↗
PubMed1994

Quantitation of perivascular monocytes and macrophages around cerebral blood vessels of hypertensive and aged rats.

The numbers of monocytes and macrophages in the walls of cerebral blood vessels were counted on perfusion-fixed frozen brain sections (16 microns) of spontaneously hypertensive rats (SHR), stroke-prone SHR (SHR-SP), normotensive Wistar-Kyoto (WKY) rats, and young (16-week-old) and old (2-year-old) normotensive Sprague-Dawley rats (SD-16w and SD-2y, respectively) using monoclonal antibodies against rat macrophages (ED2). The staining was visualized with fluorescein-labeled second antibodies. The ED2-specific staining in brain sections was restricted to macrophages in a perivascular location. The number of perivascular cells per square millimeter of high-power field was significantly greater in SHR-SP (8.6 +/- 2.1; n = 4) and SHR (6.7 +/- 0.9; n = 6) than in normotensive WKY (4.0 +/- 0.5; n = 6; p < 0.01). The number of perivascular macrophages was also greater in SD-2y (7.5 +/- 2.7; n = 9) than in SD-16w (2.9 +/- 1.8; n = 8; p < 0.01). No ED2 staining was found in the resident microglia or in the endothelial cells, which were identified by double staining with rhodamine-labeled anti-factor VIII-related antigen antibodies. The results suggest that the stroke risk factors hypertension and advanced age are associated with increased subendothelial accumulation of monocytes and macrophages. This accumulation could increase the tendency for the endothelium to convert from an anticoagulant to a procoagulant surface in response to mediators released from these subendothelial cells.

Aging↗
PubMed1994

Stiff-man syndrome.

Explore the source record for details and available documents.

Combined Modality Therapy↗