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PubMed1998

Three-dimensional structure and composition of CA3-->CA1 axons in rat hippocampal slices: implications for presynaptic connectivity and compartmentalization.

Physiological studies of CA3-->CA1 synaptic transmission and plasticity have revealed both pre- and postsynaptic effects. Understanding the extent to which individual presynaptic axonal boutons could provide local compartments for control of synaptic efficacy and microconnectivity requires knowledge of their three-dimensional morphology and composition. In hippocampal slices, serial electron microscopy was used to examine a nearly homogeneous population of CA3-->CA1 axons in the middle of stratum radiatum of area CA1. The locations of postsynaptic densities (PSDs), vesicles, and mitochondria were determined along 75 axon segments (9.1 +/- 2.0 micrometer in length). Synapses, defined by the colocalization of PSDs and vesicles, occurred on average at 2.7 micrometer intervals along the axons. Most varicosities (68%) had one PSD, 19% had 2-4 PSDs, and 13% had none. Synaptic vesicles occurred in 90% of the varicosities. One-half (53%) of the varicosities lacked mitochondria, raising questions about their regulation of ATP and Ca2+, and 8% of varicosities contained only mitochondria. Eleven axons were reconstructed fully. The varicosities were oblong and varied greatly in both length (1.1 +/- 0.7 micrometer) and volume (0.13 +/- 0.14 micrometer 3), whereas the intervaricosity shafts were narrow, tubular, and similar in diameter (0.17 +/- 0.04 micrometer) but variable in length (1.4 +/- 1.2 micrometer). The narrow axonal shafts resemble dendritic spine necks and thus could promote biochemical compartmentalization of individual axonal varicosities. The findings raise the intriguing possibility of localized differences in metabolism and connectivity among different axons, varicosities, and synapses.

Animals↗
PubMed2000

Compartmental organization and chemical profile of dopaminergic and GABAergic neurons in the substantia nigra of the rat.

The substantia nigra (SN) is a midbrain center composed of dopaminergic (DA-) and gamma aminobutyric acid (GABA)ergic (GABA-) neurons. In this study, we investigated the topographical relationship between both cell populations and their chemical profile by using single and double immunostaining for tyrosine hydroxylase (TH), glutamic acid decarboxylase (GAD), cholecystokinin (CCK), calretinin (CR), calbindin (CB), parvalbumin (PV), and nitric oxide synthase (NOS). Our results showed that DA-cells are arranged in two bands, one rostrodorsal that corresponds to the SN pars compacta (SNC), and another caudoventral that corresponds to the SN pars reticulata (SNR) and emits cell bridges that make contact with the rostrodorsal one. In the SNR, GABA-cells are arranged in dorsoventrally elongated clusters that occupy DA-cell free regions. According to cytoarchitectural, topographical, and chemical criteria, we identified ten different cell groups: five dopaminergic ones, and five GABAergic ones. Within DA-cells, we found a cell group in the dorsomedial portion of the SNC which contains CCK, CR, and CB (dmSNC); DA-cells in the SN pars lateralis (SNL) which also contain CCK, CR and CB; DA-cells in the rostral half of the SNC containing CCK and CR (rSNC); DA-cells in the SNR and the caudal half of the SNC which only express CR (cSNC-SNR), and a DA-cell group in the lateral part of the SNC that contains none of the markers studied (lSNC). Within GABA-cells, we distinguished: large GABA-cells in the SNL that contain PV; large GABA-cells in the rostrolateral part of the SNR containing PV and NOS (rlSNR), small GABA-cells in the caudomedial part of the SNR containing PV (cmSNR), and two groups of small GABA-cells in the rostromedial portion of the SNR, one of them containing CR (rmcSNR), and the other containing NOS (rmnSNR). These data suggest that over a compartmental and complementary organization, DA- and GABA-nigral cells form a mosaic of neurochemically different subnuclei which probably differ in their physiological and pharmacological properties and vulnerability to aggression.

Animals↗
PubMed1998

Protrusive activity, cytoplasmic compartmentalization, and restriction rings in locomoting blebbing Walker carcinosarcoma cells are related to detachment of cortical actin from the plasma membrane.

The dynamic events at the front of locomoting blebbing Walker carcinosarcoma cells [Keller and Bebie, Cell Motil. Cytoskeleton 33:241-251, 1996] are interpreted on the basis of an analysis of the actin cytoskeleton and its relationship to the plasma membrane in fixed cells using a novel double-staining procedure. The data show that blebs are formed where cortical actin is locally depolymerized and/or by detachment of the plasma membrane from more or less intact cortical actin layers. Dissociation between the cortical actin layer and the plasma membrane, which is stimulated by microtubule disassembly, is achieved by forward movement of the plasma membrane, rather than by retraction of the actin layer. Therefore, the detached actin layers form a boundary between the newly forming protrusions and the rest of the cell. They can be associated with "constriction rings," which we have termed "restriction rings." Detached actin layers can impede entry of organelles and the nucleus into the protrusions and thereby compartmentalize the cytoplasm. Later, detached cortical actin layers depolymerize, allowing for relaxation of the restriction rings and for forward movement of cytoplasmic organelles and the nucleus. Actin may repolymerize along the detached plasma membrane allowing for a new cycle to occur. Estimates indicate that the actin polymerization/depolymerization cycles may be largely confined to the front of blebbing cells. The findings suggest that the dynamic events at the front of blebbing metazoan cells are similar to those previously found in Amoeba proteus [Grebecki, Protoplasma, 154:98-111, 1990] but different from those found in lamellipodia.

Actins↗
PubMed1996

Confined placental mosaicism for trisomies 2, 3, 7, 8, 9, 16, and 22: their incidence, likely origins, and mechanisms for cell lineage compartmentalization.

Analysis of confined placental mosaicism (CPM) for trisomies 2, 3, 7, 8, 9, 16, and 22, in diagnostic chorionic villus sampling procedures, demonstrates apparent incidences of CPM for individual trisomies of between 9 and 91 cases per 100,000 pregnancies, with trisomy 7 being the most common. More detailed analysis of the percentage of aneuploid cells present, and the distribution of abnormality between the cytotrophoblast and extra-embryonic mesoderm cell lineages, shows a highly specific pattern for each chromosome. Theoretical considerations, in conjunction with direct observations, indicate that the overriding influence on the patterns of cell distribution seen in CPM is the distribution of aneuploid cells laid down during blastogenesis. This in turn reflects closely the origin of mosaicism from either correction of a trisomic conception or post-fertilization somatic error. The pattern of aneuploid cells for each trisomy, as seen at the end of the first trimester and later in pregnancy, can therefore be used to predict the relative contribution of meiotic and mitotic errors to CPM, and hence the likely incidences of uniparental disomy from this source, upd(16)mat being the most common (1 in 10,000 continuing pregnancies). In addition, CPM for trisomies 2, 3, and 8 shows strong evidence of a non-random distribution of aneuploid cells between the different extra-embryonic cell lineages. Analysis of comparable data from spontaneous abortion material repeats this non-random pattern for trisomies 2 and 3, and suggests that a similar phenomenon may also be occurring for trisomy 22. A non-random distribution could be attributable to selection for or against, or intolerance of, particular trisomic cells in certain lineages, but is more probably a result of either cell lineage-specific non-disjunction or consistent uneven compartmentalization of aneuploid cells during blastocyst development.

Chorionic Villi Sampling↗
PubMed1999

Quantitative 13C NMR studies of metabolic compartmentation in the adult mammalian brain.

We review the information obtained by 13C NMR methods on the metabolic compartmentation of the adult mammalian brain with emphasis on its quantitative aspects. Classical radiotracer evidence and more recent 13C NMR results support the presence in the brain of at least two glutamate pools, small and large, associated with two kinetically different tricarboxylic acid cycles localized in glia and neurons, respectively. Neuronal and glial cycles interact closely, utilizing common substrates like glucose and oxygen and exchanging a variety of metabolites including glutamate, glutamine and GABA. A model for the cerebral metabolism of (1,2-13C2) acetate has made it possible to calculate fluxes through both cycles and evaluate the exchanges of glutamate, glutamine and GABA under different physiopathological conditions. Calculated flux values through the neuronal and glial tricarboxylic acid cycles are 1.0 and 0.4 mumol/min g, respectively. In the adult normoxic brain, the small and large glutamate pools account for approximately 10% and 90% of cerebral glutamate with estimated turnover times of 1.25 and 5.8/min, respectively. Net transfers of neuronal glutamate and GABA to the glial compartment are calculated to be 0.1 and 0.04 mumol/min g while transfer of glial glutamine to the neuronal compartment is estimated as 0.1 mumol/min g. Pyruvate recycling in the adult brain occurs mainly in the synaptic terminals with a calculated flux of 0.3 mumol/min g. These flux values are altered severely in pathological states such as hypothyroidism or ischemia.

Brain↗
PubMed1998

Compartmentalization of T cell responses following respiratory infection with Bordetella pertussis: hyporesponsiveness of lung T cells is associated with modulated expression of the co-stimulatory molecule CD28.

We have used a murine respiratory challenge model to examine the local T cell responses in the lung during infection with Bordetella pertussis. T cells from lung parenchyma and airways of naive and infected mice were refractory to both antigen and mitogen stimulation in the presence of lung macrophages. Furthermore irradiated mononuclear cells from the lungs suppressed antigen and mitogen-induced proliferation, but not IFN-gamma production, by splenic T cells. Removal of macrophages and stimulation of purified lung T cells in the presence of irradiated splenic antigen-presenting cells fully restored the response to mitogen. However, T cells purified from the lung during the acute phase of infection with B. pertussis failed to proliferate or produce detectable levels of IL-2, IL-4, IL-5 or IFN-gamma in response to purified bacterial antigens. In contrast, splenic T cells from these animals produced high levels of IL-2 and IFN-gamma and proliferated strongly to a range of bacterial components. Phenotypic analysis of bronchoalveolar lavage cells during the course of infection revealed transient infiltration of neutrophils, followed by macrophages, CD4+ T cells and smaller numbers of CD8+ T cells and gammadelta+ T cells. Cell surface expression of B7 on infiltrating macrophages and CTLA-4 on T cells did not change significantly during infection. However, expression of the CD28 co-stimulatory molecule was profoundly reduced on lung T cells during the acute phase of infection. In contrast, lung T cells from mice primed by B. pertussis infection or vaccination were resistant to CD28 down-regulation. These results suggest compartmentalization of T cell responses between the lung and the periphery during B. pertussis infection and that B. pertussis may have immunomodulatory properties on local T cell populations in the lungs of naive mice.

Animals↗
PubMed1995

High grade soft tissue sarcoma of the flexor fossae. Size rather than compartmental status determine prognosis.

BACKGROUND: High grade soft tissue sarcoma arising in the popliteal space, axilla, and antecubital fossae (flexor fossae tumors) have by convention been classified as extracompartmental tumors by the accepted staging and grading criteria of the Musculoskeletal Tumor Society (MSTS). Advances in neoadjuvant chemotherapy and radiation therapy have made surgical resection more feasible. The hypothesis to be tested is that compartmental status may not be of prognostic significance if the tumor is adjusted for size, histologic grade, and distant metastasis after undergoing adjuvant chemotherapy and radiation. METHODS: From June 1976 to December 1992, 22 patients with high grade soft tissue sarcomas of the flexor fossae (Group A) were treated at UCLA Medical Center. The histologic subtypes were liposarcoma (five), synovial cell sarcoma (eight), malignant fibrous histiocytoma (four), leiomyosarcoma (two), angiosarcoma (two), and rhabdomyosarcoma (one). The popliteal fossa was the location in 11, the axilla in 10, and the antecubital fossa in 1. Wide resection was attempted in all patients after preoperative chemotherapy and radiation therapy. Amputation was performed in 5 patients because of repeated or extensive recurrent tumor. A group of 77 patients (Group B) with high grade soft tissue sarcoma located within an extremity compartment were chosen to test the hypothesis that survival of patients with tumors in the flexor fossae is equal to that of patients with intracompartmental tumors of similar size and grade if both are given adjuvant therapy. This group was chosen so that histologic subtype, size, sex, and location would be similar in the two groups. The authors selected thigh and calf tumors for comparison with popliteal fossa tumors and periscapular, deltoid, and arm tumors for comparison with axilla and antecubital fossae tumors. All of these patients had similar treatment and follow-up protocols. The median follow-up of survivors in Group A was 104 months and for patients in Group B was 79 months. RESULTS: The 5-year cumulative survival rate (Kaplan-Meier method) of patients in Group A was 76%, and 67% for those in Group B. The difference was not significant. Three patients in Group A (14%) and 17 (22%) in Group B had local tumor recurrence. Eight patients in Group A (36%) and 27 (35%) in Group B had lung metastases. Age, sex, histologic subtype, and surgical margins did not affect survival outcomes, lung metastasis, and local recurrence. However, patients with larger tumors (maximum dimension > or = 8 cm or cross-sectional area > or = 40 cm2) had significantly poorer survival, more metastases, and local recurrences. CONCLUSION: Flexor fossae sarcomas do not have a poorer prognosis than extremity intracompartmental tumors when adjusted for size, distant metastasis, and histologic grade when they are treated with adjuvant radiation therapy, chemotherapy, and surgery.

Adolescent↗
PubMed2000

Intravenous delivery of hyperpolarized (129)Xe: a compartmental model.

There is an increasing interest in the use of hyperpolarized 129-xenon (HpXe) NMR for the measurement of tissue perfusion. In this paper we present a theoretical study designed to assess the merit of intravenous HpXe delivery compared with the existing respiration techniques. A compartmental model was created to describe the behavior of the injected bolus in the circulatory system and in the lungs. The dependence of the tissue concentration on the T(1) and solubility of the Xe in the various compartments, and on injection rate, were evaluated. By this process the critical loss mechanisms are identified. It is shown that the predicted tissue concentrations of HpXe in gray and white matter are comparable using respiration or injection techniques.

Humans↗
PubMed2001

Spatial compartmentalization of signal transduction in insulin action.

Insulin resistance is thought to be the primary defect in the pathophysiology of type 2 diabetes. Thus, understanding the cellular mechanisms of insulin action may contribute significantly to developing new treatments for this disease. Although the effects of insulin on glucose and lipid metabolism are well documented, gaps remain in our understanding of the precise molecular mechanisms of signal transduction for the hormone. One potential clue to understanding the unique cellular effects of insulin may lie in the compartmentalization of signaling molecules and metabolic enzymes. We review this evidence, and speculate on how PI-3 kinase-independent and -dependent signaling pathways both diverge from the insulin receptor and converge at discrete targets to insure the specificity of insulin action.

Animals↗
PubMed2002

Heterodinuclear Ln[bond]Na complexes with an asymmetrical macrocyclic compartmental Schiff base.

Heterodinuclear lanthanide(III)-sodium(I) complexes [LnNa(L)(Cl)(2)(CH(3)OH)] (Ln=La[bond]Nd, Sm[bond]Lu), where H(2)L is a [1+1] asymmetric compartmental macrocyclic ligand containing a N(3)O(2) Schiff base and a O(3)O(2) crown-ether-like coordination site, have been prepared and characterized by IR, (1)H, (13)C, and (23)Na NMR spectroscopy, mass spectrometry, and electron microscopy. In the solid state, the lanthanide(III) ions coordinate the Schiff-base N(3)O(2) site, and the sodium ion occupies the O(3)O(2) crownlike cavity, as shown by the X-ray crystal structures of the Nd, Eu, Gd, and Yb derivatives. In these complexes, the lanthanide(III) ion is coordinated by two chlorine atoms in the trans position and by three nitrogen and two negatively charged phenol oxygen atoms of the Schiff base, and the ion is heptacoordinated with a pentagonal bipyramidal geometry. The sodium ion is coordinated by three etheric oxygen atoms and the two phenolic oxygens that act as a bridge. A methanol molecule is also coordinated in the apical position of the resulting pentagonal pyramidal polyhedron. A detailed (1)H and (13)C NMR study was carried out in CD(3)OD for both diamagnetic and paramagnetic heterodinuclear complexes [LnNa(L)(Cl)(2)(CH(3)OH)]. The complexes are also isostructural in solution, and their structures parallel those found in the solid state. Moreover, some significative distances determined in the solid state and in solution are comparable. Finally, the potential use of these complexes as molecular probes for the selective recognition of specific metal ions has been tested. In particular, their ability to act as shift reagents and the selectivity of the O(3)O(2) site towards Li(+), Ca(2+), and K(+) were investigated by (23)Na NMR spectroscopy.

Journal Article↗
PubMed1993

Morphometric study of the human ovary during compartmentalization.

The volumetric composition of the human ovary during the compartmentalization stage has been investigated using current stereological methods. Eight left ovaries removed from three fetuses (developmental age 20-25 weeks), four neonates, and one 8-month-old child all with a 46,XX karyotype, free from malformations of the genital apparatus, were completely cut obtaining serial sections and one 1 micron-thick section every 1,000 microns was examined. Ovarian volume was 30 mm3 at the 20th week of development, 36 mm3 at the 25th week, 129 mm3 at birth, and 287 mm3 at the eighth postnatal month. The primitive cortical tissue was the largest component of the fetal ovaries (17 mm3, corresponding to 60.2% of the organ). The second component was the interstitium (21% of the organ), followed by the medulla (11.8% of the organ). The primordial follicles occupied a small part of the organs: 1.8 mm3 at 20 weeks and 3.4 mm3 at 25 weeks (respectively 6.7% and 5.4% of the volumes of the relevant ovaries). At birth, most of the organ was composed of interstitial tissue (57 mm3, 44.2% of the volume) followed by the medulla (25 mm3, 20.3% of the volume). The germinal tissue occupied 46 mm3, mainly primitive cortical tissue (14.9% of the ovary) and primordial follicles (16.3% of the ovary), with a minor contribution from the antral follicles (about 3% of the ovary).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed2004

Changing intracellular compartmentalization of beta-galactosidase in the ROSA26 reporter mouse during embryonic development: a light- and electron-microscopic study.

The beta-geo (LacZ) reporter gene encodes for beta-galactosidase (beta-gal) in all cells of the ROSA26 mouse during embryonic development. As such, beta-gal activity constitutes an excellent marker for in situ labeling of expressing cells. However, the intracellular distribution of beta-gal differs between cells, and changes during embryonic development. Therefore, we studied LacZ-encoded beta-gal using light and electron microscopy in the heart, lung, liver, and small intestine on days 13 and 16 of gestation, and the kidney on day 16 of gestation in ROSA26 mice. The Bluo-gal method was carried out under standardized conditions, including fixation, washing, and incubation procedures. Intracellular beta-gal staining is encountered in a combination of membranous compartments, including the nuclear envelope, the endoplasmic reticulum, and the plasma membrane. Its exact localization depends on the cell type and is regulated during development. Therefore, one must take the compartmental transition of intracellular beta-gal staining into consideration when interpreting results obtained from experiments using ROSA26 mice.

Animals↗
PubMed2001

Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut.

Compartmentalization of proteinases, amylases, and pH in the midgut of Nauphoeta cinerea Oliv. (Blattoptera:Blaberidae) was studied in order to understand the organization of protein and starch digestion. Total proteolytic activity measured with azocasein was maximal at pH 11.5 both in anterior (AM) and posterior (PM) halves of the midgut, but the bulk of activity (67%) was found in PM. Total AM and PM preparations were fractionated on a Sephadex G-50 column and further analysed by means of activity electrophoresis and specific inhibitors and activators. The major activity in PM was classified as an unusual SH-dependent proteinase with M(r) 24,000 and pH optimum with synthetic substrate BApNA at 10.0. The enzyme was 43-fold activated in the presence of 1 mM DTT, insensitive to synthetic inhibitors of serine (PMSF, TLCK, TPCK) and cysteine (IAA, E-64) proteinases, strongly inhibited by STI, and displayed four active bands on zymograms. In PM, activities of trypsin-like, chymotrypsin-like, subtilisin-like, and cysteine proteinases were observed. Aspartic and metalloproteinases were not detected. In AM, activity of unusual SH-dependent proteinase also dominated and activity of chymotrypsin-like proteinase was observed, but their levels were much lower than in PM. Distribution of amylase activity, exhibiting an optimum at pH 6.0, was quite the opposite. The major part of it (67%) was located in AM. Treatment of amylase preparation with proteinases from AM and PM reduced amylase activity twofold. pH of the midgut contents was 6.0-7.2 in AM, 6.4-7.6 in the first and 8.8-9.3 in the second halves of PM. Thus, pH in AM is in good agreement with the optimal pH of amylase, located in this compartment, but the activity of proteinases, including the ability to degrade amylase, in such an environment is low. Active proteolysis takes place in the second half of PM, where pH of the gut is close to the optimal pH of proteinases.

Amylases↗
PubMed2002

Compartmentation of the rabbit cerebellar cortex.

The cytoarchitecture of the adult rabbit cerebellum is revealed by using zebrin II/aldolase c immunocytochemistry in both wholemount and sectioned material. Zebrin II is expressed by approximately half of the Purkinje cells of the cerebellar cortex. In most regions these form a symmetrical array of zebrin II positive and negative parasagittal bands. Four transverse expression domains are identified in the vermis: (1) an anterior zone, comprising four narrow bands, one at the midline and three laterally to either side, extending throughout the anterior lobe to the primary fissure; (2) a central zone with broad immunoreactive bands separated by narrow zebrin II negative bands that disappear caudally to leave no apparent compartmentation; (3) a posterior zone with prominent alternating zebrin II positive and negative bands; and (4) a nodular zone in which all Purkinje cells express zebrin II. In the hemispheres a striped topography is found in lobules HVI, HVII, and crus I, and all Purkinje cells are zebrin II+ in the flocculus and paraflocculus. Because of its importance for the classical conditioning of the eyeblink response, we made a detailed analysis of lobule HVI of the hemisphere. The immunocytochemical data show a complex substructure within HVI with three prominent zebrin II positive bands (probably homologous with P4a+, P4b+, and P5+ of rodents) separated by two zebrin II negative regions (P4- and P4b-). Thus, the organization of the rabbit cerebellum is consistent with the patterns described previously for rat, mouse, and opossum and suggests that there may be a common ground plan for the mammalian cerebellum.

Animals↗
PubMed2002

Striate cortex in dichromatic and trichromatic marmosets: neurochemical compartmentalization and geniculate input.

The superficial layers of primate striate cortex (V1) contain a regular pattern of dense staining for cytochrome oxidase (CO) reactivity ("blobs") that receive direct input from the koniocellular layers of the lateral geniculate nucleus. It has been suggested that the blob regions are dedicated to processing color information. Here, the neurochemical compartmentalization of blobs and their input from the lateral geniculate nucleus (LGN) was measured in marmosets (Callithrix jacchus) identified as having either dichromatic or trichromatic color vision. In all animals, layer III of V1 showed a patchy distribution of CO. The spatial density of CO blobs (mean, 4.6 blobs/mm(2); range, 3.9-5.5), blob diameter, and the proportion of cortical area within blobs was not significantly different in dichromats and trichromats. The LGN input was studied by injecting retrograde tracer into V1. The koniocellular layers of the LGN contribute 11% of all relay cells, and form the only geniculate input to upper layer III of V1. Only half of all relay cells in the KC layers express calbindin. There is no obvious difference between dichromats and trichromats in the pattern of the geniculate projection to V1. It is concluded that the trichromatic phenotype is not associated with changes in the gross anatomy, neurochemistry, or organization of the geniculate afferents to the superficial layers of V1.

Animals↗
PubMed2004

Functional compartmentalization in the flocculus and the ventral dentate and dorsal group y nuclei: an analysis of single olivocerebellar axonal morphology.

The cerebellar cortex consists of multiple longitudinal bands defined by their olivocerebellar projection. Single olivocerebellar axons project to a narrow longitudinal band in the cerebellar cortex and to the cerebellar nucleus with their axon collaterals. This olivocortical and olivonuclear organization is related to the functional compartmentalization of the cerebellar system. To reveal the detailed morphologic organization in the flocculus and the cerebellar and vestibular nuclei, we examined olivocerebellar projection by reconstructing the entire trajectories of 19 single olivofloccular axons and by anterograde mapping with biotinylated dextran in the rat. The flocculus was composed of 12 longitudinal band-shaped compartments that subdivided 5 previously described zones. These longitudinal bands were innervated differentially by the caudal and rostral portions of the dorsal cap (DC) and the ventrolateral outgrowth (VLO) and the rostral pole of the medial accessory olive. Single olivofloccular axons with an average of 5.1 climbing fibers usually projected to a single longitudinal band in the flocculus and to the ventral dentate or dorsal group y nucleus with their collaterals. DC neurons projected moderately to the rostrolateral portion of the ventral dentate nucleus, whereas VLO neurons projected densely to the medial portion of the ventral dentate nucleus and the dorsal group y nucleus with rostrocaudal topography. DC and VLO neurons did not project to the vestibular nuclei, although floccular Purkinje cells projected to the vestibular, ventral dentate, and dorsal group y nuclei. The fine morphologically identified longitudinal bands and topographic olivonuclear projections were correlated with previous electrophysiologically defined functional zones in the flocculus and inferior olive.

Animals↗
PubMed2004

Compartmentation of the mouse cerebellar cortex by sphingosine kinase.

Classic cerebellar anatomy is based on the characteristic array of lobes and lobules. However, there is substantial evidence to suggest that more fundamental architecture is built around arrays of parasagittal stripes, which encompass both the inputs and outputs of the Purkinje cells (PCs). Sphingosine kinase (SPHK) is an enzyme that converts sphingosine (Sph) into sphingosine-1-phosphate (S1P). Recent reports have indicated that ceramide, Sph, and S1P play a role in cell survival, growth, and differentiation in several cell types, including neurons. In this study, we examined the localization of SPHK in the mouse cerebellum by using immunohistochemistry. Anti-SPHK immunoreactivity appeared in the cerebellar molecular layer and the PC membranes. The staining pattern is striped. In the molecular layer, the staining pattern probably reflects dendritic spines and dendrites. By electron microscopy, peroxidase reaction product was deposited within dendrites especially along the plasma membranes near spines. Seen at higher magnification, the staining was in and near the postsynaptic complexes. By double immunostaining, the striped pattern of SPHK expression was shown to be identical to that revealed by anti-zebrin II, although the subcellular distribution within PC's is not. This is the first demonstration of the cerebellar compartmentation of an enzyme related to lipid metabolism, and as such, it provides an insight into the roles of SPHK and formation of S1P. The selective expression of SPHK in the zebrin II-immunoreactive PCs may explain their resistance to cell death when ceramide metabolism is disrupted, as in the acid sphingomyelinase knockout model of Niemann-Pick type A/B disease.

Amino Acid Sequence↗
PubMed2005

Morphological features, distribution and compartmental organization of the nicotinamide adenine dinucleotide phosphate reduced-diaphorase interneurons in the human striatum.

Striatal nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-positive (+) cells are one of the major classes of striatal interneurons. The present study analyzes their somatodendritic morphology, distribution pattern, and compartmental organization in the caudate nucleus (CN) and putamen (Put) of nine normal human brains. The following striatal territories are examined: 1) the precommissural head of the CN; 2) the postcommissural head of the CN; 3) the body of the CN; 4) the gyrus of the CN; 5) the tail of the CN; 6) the precommissural Put; and 7) the postcommissural Put. Three morphologically distinct types of NADPH-d+ neurons were found in each of these territories. The two most common NADPH-d+ neurons displayed an ovoid or triangular perikaryon from which several thick primary dendrites emerged, although much less numerous, bipolar-shaped NADPH-d+ cells were also observed. The highest density of NADPH-d+ neurons was found in the gyrus of the CN, followed by the body of the CN, tail of the CN, postcommissural head of the CN, postcommissural Put, precommissural head of the CN, and precommissural Put. The matrix was the striatal compartment with the densest NADPH-d+ neuronal population. Some of these cells also occurred in the center and peripheral regions of the striosomes located in the head of the CN and in the Put. In the body and gyrus of the CN, the striosomes were largely devoid of these striatal interneurons. Knowledge of the density and distribution of these interneurons should advance our understanding of the organization of the normal human striatum and help to evaluate the effects of neurodegenerative processes on cell density.

Adult↗