Biomedical subjects

F G Wouterlood

Publications and source records attributed to F G Wouterlood.

At least 55 records · Page 3Linked to original sources

PubMed1988

Mixed-junction axon terminals on identified principal abducens motoneurons in the monitor lizard.

Motoneurons in the principal abducens nucleus of the monitor lizard Varanus exanthematicus were identified by retrograde labeling following application of horseradish peroxidase to the abducens nerve. The ultrastructure and synaptology of thirty labeled neurons were studied. We observed a type of axon terminal which forms mixed junctions with the cell bodies and the initial axon segments of labeled motoneurons. The juxtaposed membranes of the terminals and the motoneurons display gap junctions and small asymmetric synaptic specializations. The mixed-junction terminals contain spherical synaptic vesicles which are located immediately adjacent to the synaptic junction. They may originate from local circuit neurons or from neurons extrinsic to the principal abducens nucleus.

Animals↗

PubMed1988

Innervation of histaminergic neurons in the posterior hypothalamic region by medial preoptic neurons. Anterograde tracing with Phaseolus vulgaris leucoagglutinin combined with immunocytochemistry of histidine decarboxylase in the rat.

By means of anterograde neuroanatomical tracing with Phaseolus vulgaris leucoagglutinin (PHA-L) combined with immunohistochemistry of histidine decarboxylase (HDC), we studied in the rat whether the histaminergic neurons in the posterior hypothalamic region are innervated by fibers arising from neurons in the medial preoptic region (MPO). We injected the tracer at various locations in the MPO. Following survival, frozen brain sections were dual-stained according to a protocol using PHA-L and HDC immunocytochemistry. From all parts of the MPO, PHA-L-labeled fibers course to ipsi- and contralateral clusters of histaminergic neurons located in the posterior hypothalamus. Varicosities on the PHA-L-labeled fibers can be observed in close association with HDC-immunoreactive cell bodies and dendrites in all the histaminergic cell clusters in the posterior hypothalamus. These associations suggest synaptic connectivity.

Animals↗

PubMed1988

Synaptic connections between primary trigeminal afferents and accessory abducens motoneurons in the monitor lizard, Varanus exanthematicus.

We studied the anatomical pathway underlying the nictitating reflex in the monitor lizard Varanus exanthematicus by the anterograde degeneration technique combined with retrograde transport of horseradish peroxidase (HRP) and electron microscopy. After application of HRP to the abducens nerve, retrogradely labeled neurons were observed in the ipsilateral principal and accessory abducens motor nuclei. The transection, in the same experiments, of the root of the trigeminal nerve resulted in massive degeneration of myelinated fibers in the descending trigeminal tract. In the ipsilateral accessory abducens nucleus, we observed electron-dense degenerating axon terminals that formed asymmetric synaptic contacts with the primary and secondary dendrites of large neurons retrogradely labeled with HRP. A few of the degenerating terminals could be traced in serial sections to myelinated axons. No terminal degeneration was found in the contralateral accessory abducens nucleus or in the ipsilateral and contralateral principal abducens nuclei. The present results are complementary with the findings of previous light microscopic experimental tracing studies (Barbas-Henry, H.A., and A.H.M. Lohman, J. Comp. Neurol. 1986, 254:314-329; see also J. Comp. Neurol. 1988, 267:370-386), and strongly suggest the existence in Varanus of a monosynaptic, unilateral reflex pathway in which trigeminal fibers, presumably originating from the cornea, synapse with motoneurons of the bursalis and retractor bulbi muscles, which are located in the accessory abducens nucleus. This monosynaptic pathway may mediate a rapid unilateral eyeball retraction and nictitating membrane extension.

Abducens Nerve↗

PubMed1988

Anterograde neuroanatomical tracing with Phaseolus vulgaris-leucoagglutinin combined with immunocytochemistry of gamma-amino butyric acid, choline acetyltransferase or serotonin.

In order to associate specific fiber projections in the central nervous system with specific target neurons, procedures were developed in which the anterograde neuroanatomical tracing technique utilizing Phaseolus vulgaris-leucoagglutinin (PHA-L) is combined with immunocytochemistry of three (different) neuronal markers: gamma-amino butyric acid, choline acetyltransferase, and serotonin. A double, indirect, peroxidase-antiperoxidase staining method is used on free-floating brain sections. The primary antiserum against the PHA-L (first primary antiserum) is mixed with the primary antiserum against the neuronal marker (second primary antiserum). These primary antisera are raised in different animal species. Following the incubation in the cocktail of two secondary antisera. The transported PHA-L is then visualized by incubation in a peroxidase-antiperoxidase complex and subsequent reaction with nickel-enhanced diaminobenzidine/H2O2 (blue reaction product in PHA-L-labeled neurons and fibers). Incubation is continued with peroxidase-antiperoxidase antibodies raised in the animal species in which the second primary antiserum is developed, and the staining is completed by treatment with diaminobenzidine/H2O2 (brown reaction product in target neurons). The present results suggest that PHA-L-tracing can be combined with immunocytochemistry of a variety of target neuron-related antigens.

Animals↗

PubMed1988

Immunocytochemical applications in neuroanatomy. Demonstration of connections, transmitters and receptors.

In the present paper we review immunocytochemical methods for anterograde tracing with the lectin Phaseolus vulgaris-leucoagglutinin (PHA-L), combined PHA-L tracing - neurotransmitter immunocytochemistry, and the immunocytochemical localization of receptor proteins. These methods will be mainly illustrated by examples from tracing- and neurotransmitter studies on the cholinergic basal forebrain system. The morphology of PHA-L labeled neurons strongly resembles that of Golgi impregnated neurons. The complete axonal trajectories and patterns of presynaptic endings of PHA-L labeled neurons are visualized, both for light- and electron microscopic application. PHA-L-tracing can very well be combined with second immunocytochemical labeling procedures. In this way, traced pathways can be studied in their relation to chemically identified fiber systems or target neurons. Application of immunocytochemistry for the localization of the muscarinic acetylcholine receptor, albeit in its early stages, holds great promise for the near future.

Fluorescent Antibody Technique↗

PubMed1988

The connections between the septum-diagonal band complex and histaminergic neurons in the posterior hypothalamus of the rat. Anterograde tracing with Phaseolus vulgaris-leucoagglutinin combined with immunocytochemistry of histidine decarboxylase.

The connections between nuclei of the septum-diagonal band complex and the clusters of histaminergic neurons in the posterior hypothalamic region were studied with a dual-labeling procedure in which anterograde neuroanatomical tracing with Phaseolus vulgaris-leucoagglutinin was combined with immunohistochemistry of histidine decarboxylase. Phaseolus vulgaris-leucoagglutinin was injected in the medial and lateral septal nuclei, and in various parts of the nuclei of the diagonal band of Broca. The fibers arising from the medial and lateral septal nuclei traverse the vertical limb of the diagonal band and, in part, join the medial forebrain bundle in the preoptic area. Other fibers descend diffusely through the lateral hypothalamus to the posterior hypothalamus, or course in a bundle of fibers ensheathing the fornix. The nuclei of the diagonal band project via the medial forebrain bundle and the diffuse pathway to the posterior hypothalamic region. All the nuclei of the septum-diagonal band complex, with the exception of the medial and lateral parts of the nucleus of the horizontal limb of the diagonal band, project to clusters of histaminergic neurons. These projections exhibit the following arrangement: along the axis lateral septal nucleus-medial septal nucleus-vertical limb of the diagonal band-medial part of the horizontal limb of the diagonal band, the septohypothalamic fibers decrease in density and distribute to fewer clusters of histaminergic neurons. Varicosities on the labeled fibers are formed in close proximity to the cell bodies and dendrites of the histaminergic neurons.

Animals↗

PubMed1988

Basal forebrain inputs to the interpeduncular nucleus in the rat studied with the Phaseolus vulgaris-leucoagglutinin tracing method.

The connections between the basal forebrain and the interpeduncular nucleus (IP) were studied in the rat using the anterograde transport of Phaseolus vulgaris-leucoagglutinin (PHA-L). PHA-L was injected in the septum-diagonal band complex, the preoptic area, the substantia innominata, the globus pallidus, and the ventral pallidum. In a number of cases sections of the IP were double-immunostained for PHA-L and serotonin. Only following PHA-L injections in the medial septal nucleus and the nucleus of the vertical limb of the diagonal band, were substantial terminations found throughout all subnuclei of IP. Following injections in the medial and lateral preoptic area labeling was confined to the caudal part of IP. This finding suggests that the area in the basal forebrain that contributes to these projections is smaller than has been indicated by previous retrograde tracing studies. Labeled fibers reach the IP predominantly via the medial forebrain bundle. Only a very small number of fibers reaches the ventral mesencephalon, and possibly the IP, via the stria medullaris and the fasciculus retroflexus. The highest density of terminations was seen in the apical subnucleus. The apical subnucleus contains serotonin-immunoreactive neurons, in the direct vicinity of which varicosities on the labeled fibers were seen. This finding suggests innervation of the serotonergic neurons by fibers from the medial septum and preoptic area.

Afferent Pathways↗

PubMed1988

Immunohistochemical localization of monoamines and cyclic nucleotides. Their application in quantitative immunofluorescence studies and tracing monoaminergic neuronal connections.

We have described immunocytochemical methods for the direct visualization of monoamine- and cGMP-containing neurons, using antibodies to the primary or secondary messengers themselves. The specificity and affinity of these antibodies were determined using quantitative immunofluorescence of gelatin models, as non-biological models, to which the native substances and their possibly cross-reacting compounds were incorporated. The use of retro- and anterograde tracers both in conjunction with immunohistochemical procedures provides the possibility to characterize transmitter specifically afferent and efferent pathways. With the presented double-label immunocytochemical procedures it is feasible to visualize and trace a projection between two brain areas, and in addition to specify the transmitters which are involved in their afferents and efferents and their target neurons and neurons of origin. Using the SCG, as a biological model, we could demonstrate that cGMP levels in individual cells could be elevated by cholinergic agonists. Moreover, using quantitative immunofluorescence of cGMP as a post- or presynaptic marker we have the possibility to measure the post-/presynaptic effects of monoamines or neuropeptides in individual neurons.

Animals↗

PubMed1987

Projection from the prefrontal cortex to histaminergic cell groups in the posterior hypothalamic region of the rat. Anterograde tracing with Phaseolus vulgaris leucoagglutinin combined with immunocytochemistry of histidine decarboxylase.

We investigated the projection from the infralimbic division of the prefrontal cortex (area 25) to histaminergic neurons in the posterior hypothalamic area. Phaseolus vulgaris-leucoagglutinin (PHA-L) was injected in the prefrontal cortex of rats. Frozen brain sections were subjected to combined PHA-L and histidine decarboxylase (HDC)-peroxidase immunocytochemistry, using nickel-enhanced diaminobenzidine (blue reaction product) to visualize the transported PHA-L, and diaminobenzidine (brown reaction product) to visualize simultaneously the HDC-containing neurons. PHA-L-labeled fibers could be seen coursing in the capsula interna, leaving the telencephalon via the anterior thalamic radiation and the medial forebrain bundle. In the lateral and posterior hypothalamic areas, PHA-L-labeled fibers leave the medial forebrain bundle and traverse the nuclei containing HDC-immunoreactive neurons. Varicosities on the PHA-L-labeled fibers, the majority of which occur en passant, could be observed in close association with the HDC-immunoreactive neurons. The results suggest that the hypothalamic histaminergic neurons receive afferent synaptic input from neurons of the infralimbic division of the prefrontal cortex.

Animals↗

PubMed1987

Double-label immunocytochemistry: combination of anterograde neuroanatomical tracing with Phaseolus vulgaris leucoagglutinin and enzyme immunocytochemistry of target neurons.

By the neuroanatomical tracing technique based on uptake, transport, and immunocytochemical detection of injected Phaseolus vulgaris leucoagglutinin (PHA-L), fiber trajectories of labeled neurons can be followed with great accuracy to their termination areas. To further analyze the connectivity of these fibers, the target neurons must be chemically characterized. In vibratome and frozen sections of rat brain, we tried to visualize PHA-L-labeled fibers and, simultaneously, the target neuron-related antigen. As a model system we used the projection from the pre-frontal cortex to histaminergic neurons in the posterior hypothalamic region. We tested "sequential" and "pooled" immunocytochemical procedures. In the sequential procedure, the two antigens are detected by two successive and complete immunocytochemical staining procedures, with primary antibodies raised in different animal species and with different chromogens for the final visualization. In the pooled procedure, the sections are incubated with mixtures of primary and secondary antibodies, after which the procedure is similar to the sequential procedure. We obtained excellent results on vibratome sections with a sequential procedure using first conventional peroxidase immunocytochemistry (goat anti-PHA-L primary antibody) to visualize the transported PHA-L (brown reaction product), and subsequently alkaline phosphatase immunocytochemistry (rabbit anti-histidine decarboxylase primary antibody) to locate the histaminergic neurons (blue reaction product). The resulting preparations deteriorate, however, after 1-2 months of storage. Good results were also obtained with a double peroxidase procedure on frozen sections, using nickel-enhanced diaminobenzidine to visualize the PHA-L (dark blue reaction product), and diaminobenzidine (brown reaction product) to visualize the second antigen. The quality of these preparations is permanent.

Animals↗

PubMed1987

Stabilization of silver chromate Golgi impregnation in rat central nervous system neurons using photographic developers. II. Electron microscopy.

The silver chromate precipitate present in neurons impregnated according to the Golgi-rapid and Golgi-Kopsch procedures can be stabilized by treatment with a photographic developer. In a complementary light microscopic study the stabilizing properties of various photographic developers were tested. Kodalith, Elon-ascorbic acid, HC-110, D-19 and Neutol proved to be the most successful. In the present electron microscopic study, we studied the distribution, shape and size of the particles found in Golgi-rapid and Golgi-Kopsch-impregnated neurons by treatment with each of these developers and, simultaneously, the effect of the developer on the preservation of the ultrastructural details. The reaction product after developer-treatment of Golgi-rapid material is sufficiently stable to withstand embedding and thin sectioning, whereas in Golgi-Kopsch material additional gold chloride "toning" is necessary. In Golgi-impregnated, Kodalith-, Elon-ascorbic acid-, or HC-110-treated material the formed particles are small and located in the cytoplasm, limited by the plasma membranes of the impregnated profiles. In Golgi-impregnated, D-19 treated neurons, the formed particles are relatively coarse. The majority of these particles are within cytoplasm, but particles may also lie either across or entirely outside the plasma membranes of the impregnated profiles. A large number of the small particles in Golgi impregnated, Neutol-stabilized neurons can be seen partly or entirely outside the plasma membranes of the impregnated profiles. Good original ultrastructural preservation seems to be unaffected by developer treatment. Treatment of Golgi material with sodium bromide before stabilization (bromide substitution) results in the formation of small silver particles both inside and outside the impregnated profiles. The sodium bromide step of this procedure has an adverse effect on the preservation of ultrastructural detail.

Aminophenols↗

PubMed1986

Histaminergic neurons in the rat brain: correlative immunocytochemistry, Golgi impregnation, and electron microscopy.

Histamine-containing neurons were visualized in Vibratome--sections of rat brain with the indirect peroxidase-antiperoxidase immunocytochemical method of Sternberger (Immunocytochemistry, 2nd edition, New York: John Wiley and Sons, pp. 1-354, '79) by utilizing a primary antibody directed against L-histidine decarboxylase (HDC). Cell bodies of HDC-immunoreactive neurons are located exclusively in the posterior hypothalamus: tuberal magnocellular nucleus (TM), caudal magnocellular nucleus (CM), and post-mammillary magnocellular nucleus (PCM). With the light microscope, all the HDC-immunoreactive neurons in CM and PCM and the majority of the HDC-immunoreactive neurons in TM appear to be large neurons, with a short, thick dendrite emerging from each pole of the long axis of the oval perikaryon and one or more, thinner, nonpolar primary dendrites. In the electron microscope, it can be seen that the immunoreaction product is diffusely dispersed in the cytoplasm. The ultrastructural features of all investigated (70) HDC-immunoreactive neurons in the three nuclei, independent of their light microscopic characteristics, are remarkably similar: large, unindented, pale nucleus; a high proportion of cytoplasm to nucleus (with the exception of the medium-sized HDC-immunoreactive neurons in TM); large, perinuclear array of Golgi apparatus; numerous mitochondria; endoplasmic reticulum fragmented into numerous small cisterns; thick initial portions of the primary dendritic trunks; few axosomatic synaptic contacts. Twenty-one Golgi-Kopsch-impregnated neurons taken from CM, PCM, and TM were embedded in epoxy resin, serially sectioned, and investigated in the electron microscope. The ultrastructural characteristics typical of HDC-immunoreactive neurons were observed in all three nuclei in neurons with large cell bodies tapering into two thick, sparsely spinous primary dendrites that subsequently dichotomize into very long (up to 100 microns), nontapering, aspinous secondary dendrites. In sections taken from the posterior hypothalamic area of rats prepared in a conventional way for electron microscopy, distinct populations of large cells can be observed in TM, CM, and PCM displaying the same set of ultrastructural characteristics as the HDC-immunoreactive neurons.

Animals↗

PubMed1986

Stabilization of silver chromate Golgi impregnation in rat central nervous system neurons using photographic developers. I. Light microscopy.

Deterioration of Golgi impregnation begins immediately after impregnated tissue blocks are sectioned with the Vibratome. The first signs of deterioration are fading of delicate impregnated processes, the disruption and fragmentation of dendrites, and, eventually, fading of entire neurons. These changes can be prevented by stabilization, i.e., by converting the water soluble silver chromate Golgi precipitate into metallic silver or by replacing the silver with some other dense, insoluble material. A technique is described using photographic developers to treat Vibratome sections containing Golgi-rapid or Golgi-Kopsch impregnated CNS neurons. In this way part of the silver chromate Golgi precipitate is reduced to metallic silver, and the remaining silver chromate is then removed with sodium thiosulfate. Of the various developers tested, Kodalith and Elon-ascorbic acid gave the best results, with excellent stabilization of the most delicate structures, such as the stalks of dendritic spines and finely woven axonal plexuses. Treatment with other developers (HC-110, Neutol, D-19, D-76, D-163, Kodak Universal, Rodinal, Atomal, Diafine, Eukobrom, Microdol-X) resulted in stabilization ranging from good to poor. Good stabilization of Golgi impregnation could also be achieved by first exposing the sections to sodium bromide (bromide substitution) followed by treatment with D-19, Kodalith, Elon-ascorbic acid or HC-110. After stabilization, the sections can be counterstained with aqueous cresyl violet or with alcoholic thionin without degradation of the stabilized Golgi image. The counterstain permits exact determination of the position of impregnated neurons in cortical layers or subcortical nuclei.

Animals↗

PubMed1985

Projection of olfactory bulb efferents to layer I GABAergic neurons in the entorhinal area. Combination of anterograde degeneration and immunoelectron microscopy in rat.

Glutamic acid decarboxylase (GAD) immunoelectron microscopy in combination with anterograde degeneration was applied in rats to study the synaptic targets of olfactory bulb afferents to the lateral subdivision (LEA) of the entorhinal area (EA). Immunoreactive neurons and terminals are scattered throughout all layers of LEA. After olfactory bulb resection, terminal degeneration occurs in layer Ia of EA. Using the electron microscope we examined serial thin sections of 12 and 14 immunoreactive neurons sampled from layer Ia of the dorsal (DLEA) and ventral (VLEA) subdivisions of LEA, respectively. The morphology of all these neurons is similar: they are small (short axis 5-9 micron, long axis 7-12 micron) and possess eccentrically located, indented nuclei provided with filamentous nuclear rodlets. The immunoreactive neurons have thin, smooth dendrites which usually emerge abruptly from the somata. We observed a single cilium on 5 of the immunoreactive neurons. In layer Ia of both DLEA and VLEA, the somata of the immunoreactive neurons are contacted by degenerating, non-immunoreactive boutons showing asymmetric synaptic junctions. In addition to these boutons, 4 other categories of axo-somatic terminals can be distinguished: normal, non-immunoreactive boutons forming asymmetric synapses and containing spherical synaptic vesicles; normal, non-immunoreactive boutons with symmetric synapses and pleomorphic synaptic vesicles; normal, non-immunoreactive boutons with asymmetric synapses, containing dense-cored vesicles in addition to spherical synaptic vesicles; and normal, immunoreactive boutons with symmetric synapses and pleomorphic synaptic vesicles. It is suggested that the GAD-immunoreactive neurons which receive olfactory bulb input correspond to local circuit neurons with intralaminar axons which innervate each other as well as the distal segments of the apical dendrites of projection neurons with cell bodies in layers II and III. Thus, the olfactory input in EA seems to be wired not only for excitation of layers II and III pyramidal neurons but also for feed-forward inhibition using GABAergic intermediary neurons, strategically located in the area of termination of olfactory bulb fibers.

Animals↗

PubMed1985

Neuroanatomical tracing by use of Phaseolus vulgaris-leucoagglutinin (PHA-L): electron microscopy of PHA-L-filled neuronal somata, dendrites, axons and axon terminals.

Following iontophoretic application of the plant lectin Phaseolus vulgaris-leucoagglutinin (PHA-L) to brain areas of rats, and subsequent immunohistochemistry, reaction product can be observed with the light microscope to fill neurons completely, including their somata, dendrites, dendritic appendages and axons. Moreover, axons often show profuse collateralization and indications of termination, including numerous en passant and terminal varicosities. The present report describes a protocol for combining light microscopic examination of PHA-L-stained neurons and electron microscopy of details of their processes, including the axonal varicosities. The results support the hypothesis that axonal varicosities are the light microscopic representations of synaptic axon terminals seen in electron microscopic preparations.

Agglutinins↗

PubMed1984

Cartwheel neurons of the dorsal cochlear nucleus: a Golgi-electron microscopic study in rat.

Cartwheel neurons in rat dorsal cochlear nucleus (DCN) were studied by Golgi impregnation-electron microscopy. Usually situated in layers 1-2, cartwheel neurons (10-14 micrometers in mean cell body diameter) have dendritic trees predominantly in layer 1. The dendrites branch at wide angles. Most primary dendrites are short, nontapering, and bear only a few sessile spines. Secondary and tertiary dendrites are short, curved, and spine-laden. The perikaryon forms symmetric synapses with at least two kinds of boutons containing pleomorphic vesicles. The euchromatic nucleus is indented and has an eccentric nucleolus. The cytoplasm shows several small Nissl bodies, a conspicuous Golgi apparatus, and numerous subsurface and cytoplasmic cisterns of endoplasmic reticulum with a narrow lumen, joined by mitochondria in single or multiple assemblies. In primary dendrites mitochondria are situated peripherally, while in distal branches they become ubiquitous and relatively more numerous. Dendritic shafts usually form symmetric synapses with boutons that contain pleomorphic vesicles. The majority of the dendritic spines are provided with a vesiculo-saccular spine apparatus. All dendritic spines have asymmetric synapses. Most of these are formed with varicosities of thin, unmyelinated fibers (presumably axons of granule cells) running parallel to the long axis of the DCN or radially. These varicosities contain round, clear synaptic vesicles. On the initial axon segment few symmetric synapses are present. The axon acquires a thin myelin sheath after a short trajectory. Cartwheel neurons outnumber all other neurons in layers 1-2 (with the exception of granule cells), and presumably correspond to type C cells with thinly myelinated axons described by Lorente de Nó. The axons of these neurons provide a dense plexus in the superficial layers without leaving the DCN. The possible functional role of cartwheel neurons is discussed.

Animals↗

PubMed1984

Stellate neurons in rat dorsal cochlear nucleus studies with combined Golgi impregnation and electron microscopy: synaptic connections and mutual coupling by gap junctions.

Stellate neurons in the outer two layers of the rat dorsal cochlear nucleus (DCN) were studied by the Golgi-EM method. Stellate cell bodies are usually spherical or ovoidal and range from 9 microns to 14 microns in mean diameter. The smallest cells are situated underneath the ependymal layer and the largest cells in layer 2. Primary dendrites are short, thin and smooth and arise abruptly from the perikaryon, without a tapering main stem. Meandering secondary and tertiary dendrites extend in all directions, carry few pleomorphic spines lacking a spine apparatus and often show artifactual beading. The axons are impregnated only for a short distance (10-45 microns). The nucleus is indented, the nucleolus varies in position, and the chromatin, evenly dispersed in the centre, forms small clumps along the nuclear envelope. The cytoplasm is rich in free polyribosomes and contains scattered cisterns of granular endoplasmic reticulum. Varicosities of thin fibres, containing round synaptic vesicles, form asymmetric synapses on perikarya, dendritic shafts and spines of stellate cells. Such fibres run parallel to the long axis of the DCN or are oriented radially and are interpreted as axons of cochlear granule cells. Two kinds of bouton containing pleomorphic vesicles, one kind electron lucent and the other electron dense, form symmetric synapses on perikarya and dendritic shafts of stellate cells. The lucent boutons occur more frequently than the dense boutons, especially on the distal dendritic branches. The boutons with pleomorphic vesicles presumably represent terminals of local circuit neurons, probably the stellate and cartwheel cells. In addition, stellate cells show numerous dendro-somatic and dendro-dendritic appositions characterized by gap junctions and puncta adhaerentia. Most of the dendrites involved in these appositions resemble stellate cell dendrites and it is concluded that DCN stellate cells are coupled electrotonically with one another. The axons of stellate cells acquire a thin myelin sheath. Since the Golgi impregnation did not stain axons of stellate cells past this point, we were unable to demonstrate the synaptic targets of stellate cells.

Animals↗

PubMed1984

Transcardial perfusion fixation of the CNS by means of a compressed-air-driven device.

In the present report we describe the construction of a systemic vascular perfusion device designed to perfuse small mammals with fixatives under a constant, controlled hydrostatic pressure. The device is powered by compressed-air. The construction of the device allows the interchange of vessels containing various perfusates during the perfusion, without having to interrupt the flow or alter the hydrostatic pressure. Large volumes of fixatives can be perfused in a relatively short time, leading to good preservation of brain tissue, both for light and electron microscopical purposes.

Animals↗