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F G Wouterlood

Publications and source records attributed to F G Wouterlood.

68 records · Page 4Linked to original sources
PubMed1984

Immunocytochemical identification of GABAergic neurons in the main olfactory bulb of the rat.

With the aid of a sheep antiserum against rat brain glutamate decarboxylase (GAD), the endogenous marker for GABAergic neurons, we have labeled immunocytochemically various types of nerve cells in the main olfactory bulb of rats, with and without topic injections of colchicine. The peroxidase-antiperoxidase procedure was applied to floating Vibratome and frozen sections. A large part of the periglomerular cell population and practically all granule cells in the deep layers contain GAD-like immunoreactivity in untreated rats, while tufted and mitral cells (the projection neurons) are unstained. This observation confirms a previous study with a rabbit antiserum against mouse brain GAD, which suggested that GABAergic neurons with presynaptic dendrites contain high somatal concentrations of GAD. We show, however, that immunostaining of granule cell bodies decreases progressively from the internal plexiform layer to the deep portion of the granule cell layer. Many cell processes in the glomeruli are densely stained. They presumably represent synaptic gemmules of the numerous GAD-positive periglomerular cells, which thus could provide initial, inhibitory modulation of the afferent input. In the external plexiform layer immunostaining of the neuropil is substantially denser in the superficial half than in the deep half. This may reflect a corresponding gradient of inhibition related to unequal frequency of occurrence of synaptic gemmules of granule cell dendrites. Alternatively such a graded immunostaining of cell processes could be related to the corresponding gradient in the density of immunostaining of granule cell bodies in the deep layers, in accordance with recent data indicating that superficial and deep granule cells project their ascending dendrites respectively to superficial and deep portions of the external plexiform layer. Furthermore, we have demonstrated the presence of additional classes of GAD-positive neurons, microneurons in the external plexiform layer, small neurons in the periglomerular region, the external plexiform layer, the mitral cell layer, the internal plexiform layer, and medium-size neurons in the granule layer and the white matter. The small- and medium-size GAD-positive neurons appear weakly immunoreactive in untreated rats, but become densely stained after topic colchicine injection. Such cells presumably lack presynaptic dendrites and may correspond to different types of short axon cells demonstrated by the Golgi method.(ABSTRACT TRUNCATED AT 400 WORDS)

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PubMed1983

Terminations of olfactory afferents on layer II and III neurons in the entorhinal area: degeneration-Golgi-electron microscopic study in the rat.

The degeneration-Golgi-electron microscopy technique was used to study the termination of olfactory afferents in the entorhinal area (EA) in the rat. Following resection of the olfactory bulb, degenerating axon terminals can be observed in a superficial lamina of layer I of both medial (MEA) and lateral (LEA) part of EA. Twenty-one Golgi-impregnated cells of 7 neuronal types located in LEA were investigated with the electron microscope. Of these cells, two layer II spinous multipolar neurons and one layer III spinous pyramidal cell, all located in the ventral part of LEA (VLEA), and one layer II sparsely spined multipolar cell, located in the dorsal part of LEA (DLEA), were observed to form synaptic contact with degenerating axon terminals. Based on these findings the possibility of a 3-member neuronal chain is discussed: mitral cell of the olfactory bulb - layer II or III neuron of EA-CA3 cell or granule cell in the hippocampus.

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PubMed1983

Chemical reduction of silver chromate: a procedure for electron microscopical analysis of Golgi-impregnated neurons.

A procedure is described by which the solid silver chromate precipitate present in Golgi-impregnated neurons is reduced by a photographic developer into metallic silver grains or particles. The remaining silver chromate is subsequently removed, and the fine structure and synaptic relationships of the impregnated neurons can be studied with the electron microscope. Three developers, Hydrochinone, Kodalith and D 19 were tested on cortical neurons in Vibratome sections of rapid Golgi-impregnated rat brains. Considerable differences were observed as regards penetration of the developer into the sections, uniformity of development, size and location of the silver particles produced during the development, and the quality of preservation of the ultrastructural details both in the impregnated neurons and the surrounding neuropil. Following the chemical reduction procedure the metallic silver deposit can be converted into metallic gold by a gold toning technique. Of the 3 tested developers, Kodalith and D 19 met the demands: good ultrastructural preservation, high contrast at both light microscopic (LM) and electron microscopic (EM) levels, reliable and easy to perform, minimum of test runs. Because of the high contrast provided by Kodalith and D 19, these substances are well suited for neuroanatomical tracing studies which make use of a transport or degeneration technique combined with Golgi-EM. In contrast to Kodalith, D 19 has little effect on the ultrastructure of the impregnated cells. Therefore, this developer can also be used for ultrastructural studies of Golgi-impregnated, light microscopically identified neurons.

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PubMed1981

The structure of the mediodorsal cerebral cortex in the lizard Agama agama: a Golgi study.

A Golgi analysis was made of the cell types present in the mediodorsal cerebral cortex of the lizard Agama agama. Mediodorsal cortex can be divided into two areas, small-celled mediodorsal cortex (sMDC) and large-celled mediodorsal cortex (lMDC). Both sMDC and lMDC are four-layered cortices: superficial plexiform layer, cellular layer, deep plexiform layer and fiber layer, lMDC partially overlaps dorsal cortex (medial superposition). Using characteristics of the dendrites and criteria of location, dendritic field shape and soma size, two classes of neurons can be distinguished in sMDC. The first class consists of two types of solitary cells present in the superficial and deep plexiform layers and in the fiber layer. The second class consists of six types of pyramidal-like candelabra cells, composing the cellular layer. In lMDC solitary cells are also present in the superficial and deep plexiform layers and in the fiber layer. Large pyramidal cells of one type lie in the cellular layer. In addition, neurons of the dorsal cortex and of the ventral cell plate of Unger lie in the medial superposition area of lMDC. Throughout the entire mediodorsal cortex, protoplasmic and fibrous astrocytes and ependymal tanycytes are found.

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PubMed1980

A corticotectal projection in the lizard Agama agama.

Following lesions in the dorsal cerebral cortex of the lizard Agama agama, terminal degeneration was observed by the Fink-Heimer technique in the mediodorsal cortex, septal area, nucleus periventricularis and area lateralis of the hypothalamus after 7 days survival time. Following longer survival times (up to 28 days) diffuse terminal degeneration was found in layers 7 to 13 laterally and medially in the optic tectum. Terminal degeneration of the electron-dense type was found in electron micrographs of the same areas of the optic tectum.

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PubMed1979

Light microscopic identification and photography of Golgi impregnated central nervous system neurons during sectioning for electron microscopy.

A method is described for a rapid and systematic light microscopic documentation of Golgi impregnated neurons while they are being sectioned for electron microscopy. A drawing under the light microscope of a Golgi impregnated neuron is made first; subsequently thin sections of the tissue containing this neuron are cut in the same plane as for light microscopy. During thin sectioning the chuck containing the block is taken out of the ultramicrotome at regular intervals and placed in a special device under a light microscope. The neuron is photographed to record the stage of sectioning. Comparison of the micrographs indicates which part of the neuron and its dendritic tree are contained in the thin sections. No semithin sections are used and therefore no material is lost for reconstruction.

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PubMed1979

Skull growth after partial prospective lower beak extirpation in chick embryos.

On one side of chick embryos in stage 28, part of the prospective lower beak or the entire prospective lower beak anterior to the buccal corner was removed surgically (CLB-A and CLB-B embryos, respectively). In another group the prospective lower beak was split in the midsagittal plane (CMS embryos). The controls were shame-operated embryos (CS). The skulls of stage 39 CLB-A and CLB-B embryos showed changes in the lower beak as well as in the skull base, the pterygoid, the quadrate, the palatine, and the upper beak. Stage 39 CMS embryos showed shortening of the dentary and Meckel's cartilage. At the tip of the CMS mandible, an excessive amount of osseous material was found. The results support Dullemeijer's (1974) views concerning the issue of dependency of functional components. The value of a combined developmental and functional approach to morphology, i.e., integrated investigation of development of structure and function of the beaks and related jaw musculature, is discussed.

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PubMed1979

The influence of the lower beak on the interorbital septum-prenasal process complex in the chick embryo.

The effect of removal of the lower beak on the development of the interorbital septumprenasal process (ISPP) complex was studied in chick embryos. In normal development the angle between the ventral contour of the interorbital septum and the long axis of the prenasal process increases. At the same time the angle between the ventral contour of the interorbital septum and the basal plate increases. After surgical removal of the prospective lower beak at stage 29, the position of the entire ISPP complex was altered in stage-38 embryos and the prenasal process showed elongation. In stage-38 embryos in which the prospective upper beak had been removed at stage 29, Meckel's cartilage was elongated. It is concluded that straightening of the angle between the ventral contour of the interorbital septum and the long axis of the prenasal process is not influenced by the lower beak, whereas the position of the entire ISPP complex and the size of the prenasal process are under the epigenetic influence of the lower beak. The position and size of Meckel's cartilage are under the epigenetic influence of the upper beak.

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PubMed1977

The mutual relations of structures in the growing bill of chick (Gallus domesticus L.) and duck (Anas platyrhynchos L.) Embryos. IV. The size, shape, and position of the upper and lower bills in unilaterally microphthalmic duck embryos.

Unilaterally microphthalmic duck (DUM) embryos studied in stage 39 were obtained by damaging the right eye in stage 17. The development between stages 19 and 39 was observed in samples. After prolonged incubation, one duck hatched and reached adulthood. In DUM embryos partial crossbeak develops. Both the upper and lower bills deviate lateralwards, the upper bill more than the lower. In stage 39 a small orbit is present on the treated side. In stained and cleared heads most of the elements of the skull (the bones surrounding the orbit, the brain-case, and the upper and lower bill elements) are translated in the direction of the rudimentary orbit on the treated side. The bills are twisted around each other at the tip. Measurements of external dimensions as well as those made in stained and cleared stage-39 DUM heads show elongation of the left part of the lower bill. Except for the crossed bills, the changes found in the embryos persisted in the adult. The findings support a hypothesis concerning the mutual influence of bills during morphogenesis. The coherence of the functional cranial components in the embryo is discussed.

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PubMedDate not supplied

The in situ detectability of the neuroanatomical tracer Phaseolus vulgaris-leucoagglutinin (PHA-L).

We determined the in situ detectability of the neuroanatomical tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). The tracer was bilaterally injected in the nucleus accumbens of the ventral striatum of young adult rats. After post-injection survival periods ranging from 4.5 to 16 weeks, sections of the brain were subjected to immunocytochemical detection of the transported PHA-L. We examined the labelled neurons in the injection sites, the labelled local and efferent fibres, and the labelled terminal structures in the ventral pallidum. Up to 4.5 weeks after the injection, the PHA-L-labelled neurons in the injection site were completely stained and displayed dendrites with numerous spines. There was also good visualization of local axonal plexuses and of the efferent fibres and their varicosities along the trajectories to and in the termination areas. Six and a half weeks after the injection, the fibres coursing from the injection site to the termination area were difficult to visualize. By contrast, the injection site contained labelled cell bodies, dendrites with few spines, weakly stained fibres, and punctate labelling. In the termination areas there was a clear, punctate terminal labelling in addition to weak fibre labelling. Between 8 and 10 weeks after the injection, labelled neurons in the injection site could be visualized as well as a cloud of punctate staining in the termination area, but labelled fibres and dentritic spines were not observed. Eleven weeks after the injection, label was no longer demonstrable in terminals. After survival periods of 13 weeks and longer, the only labelled structures were weakly PHA-L-immunoreactive perikarya at the injection site, surrounded by punctate labelling.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMedDate not supplied

Compromises between penetration of antisera and preservation of ultra structure in pre-embedding electron microscopic immunocytochemistry.

Light microscopic pre-embedding immunocytochemistry on free-floating brain sections is commonly performed with antisera to which a detergent is added. For instance, the trajectories and the terminals of axons of neurons labelled by anterograde neuroanatomical tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L) are commonly visualized by immunocytochemistry, using antisera to which 0.5 per cent Triton X-100 is added. In this material the ultrastructural details are very poorly preserved. Omitting the detergent from the antisera results in no or very superficial staining. To improve the quality of ultrastructural preservation while still obtaining sufficient penetration of the antisera, we subjected vibratome sections of rat brain containing PHA-L-labelled neuronal perikarya and processes to PHA-L-immunocytochemistry in the presence, at various concentrations, of the detergents Kodak Photo-Flo 200, Triton X-100, Saponin, Nonidet P-40 or sodium deoxycholate. As controls served incubations without detergents. The addition of 0.1 per cent Photo-Flo 200 to all the immunoreagents, together with a relatively long incubation time, results in a balanced compromise between the demands of preservation of the ultrastructure and penetration of the antisera. If the PHA-L-immunocytochemistry is preceded by a short treatment with 0.05-0.1 per cent Triton X-100, the penetration is further improved, although at the expense of ultrastructural detail.

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