1D and 3D anthropometric data application on public transport vehicle layout and on oil and gas laboratories work environment design.

The goal of this paper is to present 1D and 3D anthropometric data applied to two distinct design situations: one related to the interior layout of a public transport vehicle and another one related to oil and gas laboratories work environment design. On this study, the 1D anthropometric data were extracted from the Brazilian anthropometric database developed by INT and the 3D anthropometric data were obtained using a Cyberware 3D whole body scanner. A second purpose of this paper is to present the 3D human scanning data as a tool that can help designers on decision making.

DHM simulation in virtual environments: a case-study on control room design.

This paper will present the workflow developed for the application of serious games in the design of complex cooperative work settings. The project was based on ergonomic studies and development of a control room among participative design process. Our main concerns were the 3D human virtual representation acquired from 3D scanning, human interaction, workspace layout and equipment designed considering ergonomics standards. Using Unity3D platform to design the virtual environment, the virtual human model can be controlled by users on dynamic scenario in order to evaluate the new work settings and simulate work activities. The results obtained showed that this virtual technology can drastically change the design process by improving the level of interaction between final users and, managers and human factors team.

DHM and serious games: a case-study oil and gas laboratories.

The aim in this paper is to present a research on the application of serious games for the design of laboratories in the oil and gas industries. The focus is in human virtual representation acquired from 3D scanning, human interaction, workspace layout and equipment designed considering ergonomics standards. The laboratory studies were simulated in Unity3D platform, which allows the users to control the DHM1 on the dynamic virtual scenario, in order to simulate work activities. This methodology can change the design process by improving the level of interaction between final users, managers and human factor teams. That helps to better visualize future work settings and improve the level of participation between all stakeholders.

Exenatide versus insulin glargine: a cost-effectiveness evaluation in patients with Type 2 diabetes in Switzerland.

OBJECTIVES: To investigate the long-term clinical and economic outcomes associated with exenatide versus insulin glargine as "add-on" treatments to oral therapy in individuals with Type 2 diabetes inadequately controlled with combination oral agents in the Swiss setting. METHODS: A computer simulation model of diabetes was used to project complications, life expectancy, quality-adjusted life expectancy and direct medical costs over a 35-year time horizon. Cohort characteristics and treatment effect data were derived from a 26-week randomized clinical trial comparing exenatide and insulin glargine. Modeled treatment effects included reductions in glycosylated hemoglobin (HbA1c) by -0.99% and -1.07% and in body mass index (BMI) by -0.80 and +0.55 kg/m2 with exenatide and insulin glargine respectively. Changes in systolic blood pressure and serum lipid levels were also captured. Simulations incorporated published quality of life utilities and Swiss costs from 2006. Extensive sensitivity analyses were conducted to assess the robustness of projected outcomes. Future clinical and economic outcomes were discounted at 2.5% per annum. RESULTS: In the base-case analysis exenatide was associated with comparable life expectancy (11,549 years versus 11,468 years) and an improvement in quality-adjusted life expectancy of 0.43 quality-adjusted life years (QALYs) versus insulin glargine over a 35-year time horizon. Exenatide was associated with a reduced cumulative incidence of most diabetes-related complications including an absolute reduction in myocardial infarction by 0.28%. Assuming an annual treatment cost of CHF 2,797.74 for exenatide, direct costs increased by CHF 8,378 per patient over the 35-year time horizon compared to insulin glargine. The resultant incremental cost-effectiveness ratio was CHF 19,450 per QALY gained for exenatide versus insulin glargine. CONCLUSIONS: Exenatide was associated with comparable life expectancy and an improvement in quality-adjusted life expectancy versus insulin glargine over a 35-year time horizon. Based on current standards exenatide would be a cost-effective treatment alternative to insulin glargine in Switzerland for Type 2 diabetes patients inadequately controlled on oral therapy.

Local gamma-aminobutyric acid and glutamate circuit control of hypophyseotrophic corticotropin-releasing factor neuron activity in the paraventricular nucleus of the hypothalamus.

Paraventricular corticotropin-releasing factor (CRF) neurons play a pivotal role in regulating neuroendocrine responses to stress. The mechanisms by which synaptic inputs control the activity of these neurons are not well understood. The present study was undertaken to determine the role of the intrinsic gamma-aminobutyric acid (GABA)- and glutamatergic neural circuits of the hypothalamic paraventricular nucleus (PVN) in the control of CRF neural activity. We show that in organotypic cultures of the PVN, blockade of the intrinsic GABAergic neurotransmission by the GABAA receptor antagonist bicuculline resulted in a significant increase in CRF secretion. The bicuculline-induced CRF secretory activity was abolished by the coadministration of the selective alpha-amino-3-hydroxy-5-methyl-4-isoxazoleprionic acid (AMPA)/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Electrical stimulation of the CRF cell division elicited glutamatergic extracellular field potentials that were dramatically enhanced by bicuculline and were suppressed by CNQX. These results show that the functional activity of CRF neurons in organotypic cultures of the PVN is under a tonic inhibitory influence of an intrinsic GABAergic circuit. Suppression of GABAergic transmission appears to have a permissive role for inducing an increased secretory activity of CRF neurons that is driven by an excitatory glutamatergic network via AMPA/kainate receptors.

Synaptic localization of ionotropic glutamate receptors in the rat substantia nigra.

Glutamatergic neurotransmission in the substantia nigra pars compacta and pars reticulata is mediated through N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxaline propionic acid/kainate (AMPA) type receptors as well as other glutamate receptors and is critical for basal ganglia functioning. A major glutamatergic input to the substantia nigra originates in the subthalamic nucleus, and the long-lasting stimulation of the dopaminergic cells of the substantia nigra pars compacta by the subthalamic neurons has been implicated in the pathophysiology of Parkinson's disease. The objectives of the present study were to determine the subcellular and subsynaptic localization of subunits of the N-methyl-D-aspartate and AMPA receptors in the substantia nigra, and also to determine whether co-localization of N-methyl-D-aspartate and AMPA receptor subunits occur at individual synapses. To achieve this, pre-embedding and post-embedding immunocytochemistry was applied to sections of substantia nigra using antibodies that recognize the NR1 and NR2A/B subunits of the N-methyl-D-aspartate receptor, and GluR2/3 subunits of the AMPA receptor. In both regions of the substantia nigra, immunolabelling for each of the subunits was observed in numerous perikarya and proximal dendrites. At the subcellular level, silver-intensified immunogold particles localizing N-methyl-D-aspartate and AMPA receptor subunits were most commonly present within dendrites where they were associated with a variety of intracellular organelles and with the internal surface of the plasma membrane. Post-embedding immunogold labelling revealed immunoparticles labelling for NR1, NR2A/B and GluR2/3 to be enriched at asymmetric synaptic specializations, although a large proportion of asymmetric synapses were immunonegative. Double immunolabelling revealed, in addition to single-labelled synapses, the co-localization of subunits of the N-methyl-D-aspartate receptor and subunits of the AMPA receptor at individual asymmetric synapses. Similarly, double immunolabelling also revealed the co-localization of the NRl and NR2A/B subunits of the N-methyl-D-aspartate receptor at individual asymmetric synapses. Labelling for NR1 and GluR2/3 was, on average, relatively evenly distributed across the width of the synapse with a gradual reduction towards the periphery when analysed in single sections. In summary, the present results demonstrate that AMPA and N-methyl-D-aspartate receptors are selectively localized at a subpopulation of asymmetric synapses in the substantia nigra pars compacta and reticulata and that the two receptor types, at least partially co-localize at individual synapses. It is concluded that glutamatergic transmission in the substantia nigra pars compacta and pars reticulata occurs primarily at asymmetric synapses and, at least in part, is mediated by both N-methyl-D-aspartate and AMPA receptors.

NMDA receptor content of synapses in stratum radiatum of the hippocampal CA1 area.

Glutamate receptors activated by NMDA (NMDARs) or AMPA (AMPARs) are clustered on dendritic spines of pyramidal cells. Both the AMPAR-mediated postsynaptic responses and the synaptic AMPAR immunoreactivity show a large intersynapse variability. Postsynaptic responses mediated by NMDARs show less variability. To assess the variability in NMDAR content and the extent of their coexistence with AMPARs in Schaffer collateral-commissural synapses of adult rat CA1 pyramidal cells, electron microscopic immunogold localization of receptors has been used. Immunoreactivity of NMDARs was detected in virtually all synapses on spines, but AMPARs were undetectable, on average, in 12% of synapses. A proportion of synapses had a very high AMPAR content relative to the mean content, resulting in a distribution more skewed toward larger values than that of NMDARs. The variability of synaptic NMDAR content [coefficient of variation (CV), 0.64-0.70] was much lower than that of the AMPAR content (CV, 1.17-1.45). Unlike the AMPAR content, the NMDAR content showed only a weak correlation with synapse size. As reported previously for AMPARs, the immunoreactivity of NMDARs was also associated with the spine apparatus within spines. The results demonstrate that the majority of the synapses made by CA3 pyramidal cells onto spines of CA1 pyramids express both NMDARs and AMPARs, but with variable ratios. A less-variable NMDAR content is accompanied by a wide variability of AMPAR content, indicating that the regulation of expression of the two receptors is not closely linked. These findings support reports that fast excitatory transmission at some of these synapses is mediated by activation mainly of NMDARs.

Monoclonal antibodies specific for the native, disease-associated isoform of the prion protein.

Reviewing the circumstances that have led to the first monoclonal antibody against the disease-associated form of PrP, we consider the availability of PrP knockout mice and recombinant PrP, as well as a reliable conformational screening protocol as being important prerequisites for a successful immunization approach. When considering presenting an antigen to a mouse with the goal of obtaining specific monoclonal antibodies against a misfolded or aggregated form of a host protein, it is desirable to increase the definition of a subtle conformational difference. This can be achieved by immunizing an antigen knockout mouse that has not developed self-tolerance against the respective antigen. Furthermore, if conformational isoforms and/or oligomeric forms of a protein sequence are understood to exist in an equilibrium, high and pure amounts of recombinant protein may increase the likelihood that a particular population of protein conformation passes an antigenic threshold necessary to start an immunogenic response. Pulling out the monoclonal antibodies by correct screening is essential. Screening against the pure misfolded or aggregated protein is often complicated by its poor solubility and hence the ability to immobilize. In the present case, immobilization of disease-associated PrP on nitrocellulose had been established as a conformation-sensitive screening method, allowing to "freeze" PrP in its distinguishable, disease-associated conformation. We are cautious to generalize conclusions of how to assess the generation of monoclonal antibodies against these particular protein isoforms to other diseases of protein misfolding and/or aggregation, but ultimately the present approach may inspire respective experiments.

Regional distribution and developmental changes of GluR1-flop protein revealed by monoclonal antibody in rat brain.

From immunizations of mice with a glutathione S-transferase fusion protein containing residues 724-781 of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR1-flop, two monoclonal antibodies (mAbs) were developed that differed widely in their ranges of specificity. In immunocytochemical and immunoblotting assays performed on COS-7 cells transfected with one of the eight GluR1-4-flip/flop forms, mAb 19B10 recognized all eight forms, whereas mAb 8E11 was specific for GluR1-flop. By means of synthetic peptides, the epitopes were determined to be NKWWYDKG (GluR1-flop760-767) for mAb 19B10 but GSALRNPVN (GluR1-flop740-748) plus a partial epitope, QGLL (GluR1-flop757-760), for mAb 8E11. Further analysis on synthetic peptides pointed to a potential cross-reactivity of mAb 8E11 with GluR2-4-flop variants that lacked editing at the R/G site. The contribution of such cross-reactivities in histoblot labeling patterns on adult rat brain material, however, was judged to be negligible. Histoblot patterns with mAb 8E11 were dominated by strong immunoreactivity in CA1 strata radiatum and oriens and in the dentate molecular layer, whereas the CA3 region was virtually free of labeling. This pattern and those observed at different stages of postnatal development were generally similar to regional distribution patterns previously reported in the literature for GluR1-flop transcripts. Key Words: Glutamate receptors-AMPA receptor subunits-Alternative splicing-Developmentally regulated expression-R/G site.

Assembly intracellular targeting and cell surface expression of the human N-methyl-D-aspartate receptor subunits NR1a and NR2A in transfected cells.

The intracellular trafficking, assembly, and cell surface targeting of the human N-methyl-D-aspartate receptor subunits NR1a and NR2A has been studied using both transiently and permanently transfected mammalian cell lines. The expression of either NR1a or NR2A alone does not result in significant cell surface expression of either subunit as determined by cell surface biotinylation and immunofluorescence staining. When NR1a is expressed alone large intracellular accumulations of the subunit are formed which do not co-localize with the golgi apparatus markers protein p58 and wheat germ agglutinin, but do co-localize with the endoplasmic reticulum marker calreticulin. Co-expression of NR1a and NR2A results in a reduction of these intracellular accumulations and the appearance of both subunits on the cell surface. Immunoprecipitation of NR1a from in vitro translated subunit proteins showed that NR2A could only be immunoprecipitated with NR1a when both subunits were co-synthesized in the presence of microsomes. When cells expressing NR1a and NR2A were incubated with [35S]methionine in the presence of Brefeldin-A, a drug which prevents protein transport from the endoplasmic reticulum, NR2A could be immunoprecipitated by an antiserum specific for NR1a. Together these results suggest that the NMDA receptor subunits are assembled in the endoplasmic reticulum and that co-synthesis of the subunits is necessary for their association and their successful cell surface targeting.

Plasticity of agonist binding sites in hetero-oligomers of the unitary glutamate receptor subunit XenU1.

Two subunits from Xenopus, XenNR1G and the "short" subunit XenU1, have previously been coexpressed to form a unitary (NMDA/non-NMDA type) glutamate receptor. We now show that an antibody to XenNR1G or an antibody to XenU1 precipitates the binding sites of both XenNR1G and XenU1, with the recombinant subunits or with solubilised Xenopus brain membranes, i.e., the combination occurs in vivo. The expressed XenU1 subunits are in the cell membrane and oriented correctly. XenU1 binds not only kainate with high affinity (K(D) 1.2 nM at 25 degrees C), but also the glycine site antagonist 5,7-dichlorokynurenic acid (DCKA). DCKA, GTP, or GTPgammaS displaces competitively all of the bound [3H]kainate, but glycine has no effect. The results suggest that a common binding site for kainate, DCKA, and GTP can exist on XenU1. In the XenNR1G/XenU1 complex, the kainate affinity is lowered eightfold, whereas the DCKA affinity is considerably increased (K(D) 147 nM). Only 18% of the binding to the complex has the properties of the NMDA receptor glycine site, the rest being due to switching of the high-affinity kainate site of XenU1 (low-affinity DCKA) to a high-affinity DCKA (low-affinity kainate) conformation. Surprisingly, a mammalian NR2 subunit can also combine with XenU1, and this introduces similar reciprocal changes in the binding of kainate and DCKA. The combined evidence suggests a common basic mode of agonist site formation in different subunit types of the ionotropic glutamate receptors.

Glutamate-like immunoreactivity in ascending spinofugal afferents to the rat periaqueductal grey.

The midbrain periaqueductal gray is a key structure for the mediation of an integrated defence behaviour. Although a prominent role for glutamate in PAG mechanisms is supported by both behavioural and morphological studies, whether PAG afferents conveying somatosensory information constitute a source of glutamatergic input to the PAG remains unknown. Here, we have compared the projection pattern of orthogradely-labelled spinoannular fibres with the distribution of glutamate-like immunoreactivity in the PAG at the light microscopic level. Transaxonal labelling was observed throughout the whole rostrocaudal axis of the PAG except for the dorsolateral regions. Cell-processes and terminal-reminiscent puncta were strongly immunoreactive in all PAG regions, including the dorsolateral areas. To ascertain whether glutamate-immunoreactive puncta observed at light microscopy indeed constituted axon terminals of the spinoannular system, glutamate-like immunoreactivity was assessed in orthogradely-labelled synaptic terminals using a post-embedding immunogold procedure for electron microscopy. Quantitative analysis of gold particle densities revealed over twice as strong an immunoreactivity in anatomically-identified spinoannular axon terminals as in dendrites postsynaptic to them, perikarya and inhibitory Gray II synapses, as well as an over 5-fold heavier immunolabelling than in glial profiles. These findings reveal that glutamate is accumulated in synaptic terminals of the spinoannular system, supporting a neurotransmitter role for this acidic amino acid in spinofugal afferents to the PAG.

Prion (PrPSc)-specific epitope defined by a monoclonal antibody.

Prions are infectious particles causing transmissible spongiform encephalopathies (TSEs). They consist, at least in part, of an isoform (PrPSc) of the ubiquitous cellular prion protein (PrPC). Conformational differences between PrPC and PrPSc are evident from increased beta-sheet content and protease resistance in PrPSc. Here we describe a monoclonal antibody, 15B3, that can discriminate between the normal and disease-specific forms of PrP. Such an antibody has been long sought as it should be invaluable for characterizing the infectious particle as well as for diagnosis of TSEs such as bovine spongiform encephalopathy (BSE) or Creutzfeldt-Jakob disease (CJD) in humans. 15B3 specifically precipitates bovine, murine or human PrPSc, but not PrPC, suggesting that it recognizes an epitope common to prions from different species. Using immobilized synthetic peptides, we mapped three polypeptide segments in PrP as the 15B3 epitope. In the NMR structure of recombinant mouse PrP, segments 2 and 3 of the 15B3 epitope are near neighbours in space, and segment 1 is located in a different part of the molecule. We discuss models for the PrPSc-specific epitope that ensure close spatial proximity of all three 15B3 segments, either by intermolecular contacts in oligomeric forms of the prion protein or by intramolecular rearrangement.

Light microscopic comparison of the patterns of glutamate-like and homocysteate-like immunoreactivities in rat dorsal lateral geniculate after combined visual cortical and retinal ablations.

To study the contribution of retinal and cortical afferents to the patterns of glutamate- and homocysteate-like immunoreactivities in dorsal lateral geniculate, combined retinal and cortical ablations were performed in rats. In controls, glutamate immunoreactivity was in terminal-like dots and neurons. Homocysteate immunoreactivity was in small puncta. In lesioned animals, most glutamate-immunoreactive dots disappeared. In contrast, abundant puncta resembling parts of glial cells were immunoreactive for homocysteate.

Distribution of GABA, glycine, and glutamate immunoreactivities in the vestibular nuclear complex of the frog.

This study describes the localization of gamma-aminobutyric acid (GABA), glycine, and glutamate immunoreactive neurons, fibers, and terminal-like structures in the vestibular nuclear complex (VNC) of the frog by using a postembedding procedure with consecutive semithin sections at the light microscopic level. For purposes of this study, the VNC was divided into a medial and lateral region. Immunoreactive cells were observed in all parts of the VNC. GABA-positive neurons, generally small in size, were predominantly located in the medial part of the VNC. Glycine-positive cells, more heterogeneous in size than GABA-positive cells, were scattered throughout the VNC. A quantitative analysis of the spatial distribution of GABA glycine immunoreactive cells revealed a complementary relation between the density of GABA and glycine immunoreactive neurons along the rostrocaudal extent of the VNC. In about 10% of the immunolabeled neurons, GABA and glycine were colocalized. Almost all vestibular neurons were, to a variable degree, glutamate immunoreactive, and colocalization of glutamate with GABA and/or glycine was typical. GABA, glycine, or glutamate immunoreactive puncta were found in close contact to somata and main dendrites of vestibular neurons. A quantitative analysis revealed a predominance of glutamate-positive terminal-like structures compared to glycine or GABA containing profiles. A small proportion of terminal-like structures expressed colocalization of GABA and glycine or glycine and glutamate. The results are compared with data from mammals and discussed in relation to vestibuloocular and vestibulo-spinal projection neurons, and vestibular interneurons. GABA and glycine are the major inhibitory transmitters of these neurons in frogs as well as in mammals. The differential distribution of GABA and glycine might reflect a compartmentalization of neurons that is preserved to some extent from the early embryogenetic segmentation of the hindbrain.

Immunohistochemical localiztion of homocysteate in human primary visual cortex.

Polyclonal and monoclonal anti-homocysteate antibodies were used with a postembedding immunohistochemical method for light microscopy to localize homocysteate-like immunoreactivity in human primary visual cortex. Densely accumulated dots of diverse size resembling astrocytic processes were labelled in supragranular layers, mainly in layers I and II. Some glial elements intermingled with fibre bundles in the white matter, and astrocytic endfeet in the vicinity of capillaries were also stained. In addition, very few round or elongated neuronal cell bodies in layer IVc were intensely homocysteate immunoreactive. These observations extend to human primary visual cortex previous studies on the preferential localization of L-homocysteate in glia.

Glutamate-like immunoreactivity in synaptic terminals of the posterior cingulopontine pathway: a light and electron microscopic study in the rabbit.

A postembedding immunoperoxidase method for light microscopy was used to localize glutamate-like immunoreactivity in the rabbit basilar pontine nuclei. Labelled fibre bundles, neuronal cell bodies and numerous puncta of diverse size were heavily glutamate immunoreactive throughout all subdivisions of the pontine nuclei. To determine whether some of the glutamate-immunoreactive puncta were synaptic terminals of posterior cingulate cortical neurons, a double-labelling technique involving an anterograde tract-tracing method and a postembedding immunogold procedure for electron microscopy was used. A quantitative evaluation of gold particle densities revealed that anterogradely labelled cingulopontine synaptic terminals were about twice as immunoreactive as their postsynaptic dendrites, perikaryal and glial profiles and about three times more than symmetric synaptic terminals. The present results indicate that the posterior cingulopontine projection contains high levels of glutamate at its synaptic terminals. This observation provides further support to the role for glutamate as a neurotransmitter in the corticopontine pathway.

Alterations in glutamate but not GABAA receptor subunit expression as a consequence of epileptiform activity in vitro.

The consequences of epileptiform discharge on the expression of glutamate and GABA receptors were examined by in situ hybridization histochemistry after treatment of rat hippocampal slice cultures with convulsants. Application of 500 microM picrotoxin for two days led to decreases in the messenger RNA levels for the N-methyl-D-aspartate receptor subunits, NR2A and NR2B, and for the non-N-methyl-D-aspartate receptor subunits, glutamate receptors 1 and glutamate receptors 2, to about 50% of the levels seen in control cultures. Messenger RNA levels for the N-methyl-D-aspartate receptor subunit, NR1; the non-N-methyl-D-aspartate receptor subunits, glutamate receptors 3 and 4; the high-affinity kainate receptor subunits 1 and 2; and the GABAA receptor subunits, alpha 2, beta 2, gamma 2 were unchanged. Decreased levels of expression were no longer seen five days after removal of convulsant. The down-regulation could be prevented by co-application of both the non-N-methyl-D-aspartate and N-methyl-D-aspartate receptor antagonists, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and dizocilpine maleate, but not by applying each alone. Application of CNQX or dizocilpine maleate in the absence of picrotoxin also resulted in changes in glutamate receptor expression. We suggest that the convulsant-induced reduction in glutamate receptor expression leads to a decreased excitability in these cultures, and that this down-regulation represents a compensatory reaction of hippocampal pyramidal cells to enhanced excitatory input.

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.

Changes in the pattern of glutamate-like immunoreactivity in rat superior colliculus following retinal and visual cortical lesions.

We have investigated the pattern of glutamate-like immunoreactivity in the superficial layers of the rat superior colliculus by means of postembedding immunocytochemical methods for light and electron microscopy. At the light microscopic level, labelling was faintly to moderately intense in most perikarya of the stratum zonale, stratum griseum superficiale and stratum opticum. Furthermore, strong glutamate-immunoreactive terminal-like elements were accumulated most densely in stratum zonale, stratum griseum superficiale and stratum opticum. At the electron microscopic level, a postembedding immunogold method revealed that the vast majority of those labelled elements corresponded to retinal and visual cortical terminals. These profiles were about twice as heavily labelled as their postsynaptic partners. To determine the contribution of retinal and cortical afferents to the pattern of glutamate-like immunoreactivity, rats were subjected to right retinal ablation, left cortical ablation or combined right retinal and left cortical ablations. After retinal ablation, strongly labelled perikarya were observed in the retinorecipient layers. Furthermore, a prominent loss of glutamate-immunoreactive terminal-like elements occurred in stratum zonale and stratum griseum superficiale. Ipsilateral superior colliculus to cortical ablation exhibited subtle changes characterized by a moderate increase in perikaryal immunostaining in stratum zonale, stratum griseum superficiale and stratum opticum and by an apparent discrete reduction of labelled dots in stratum griseum superficiale and stratum opticum. In cases with combined lesions, strongly immunoreactive cell bodies and dendrites were accompanied by a massive disappearance of labelled terminal-like elements in stratum zonale, stratum griseum superficiale and stratum opticum. The effect of retinal and visual cortical ablations on the pattern of glutamate-like immunoreactivity suggests that these afferents are the major sources for glutamate-immunoreactive terminals in the rat superior colliculus. In addition, these findings provide further evidence for glutamate as neurotransmitter in the visual pathways studied.