摘要:

AbstractWe have investigated the structural and histochemical features of the blood‐brain barrier (b‐bb) in both adults and embryos of chicken (Gallus domesticus, White Leghorn) and quail (Corturnix coturnixjaponica). We found that brain endothelial cells of both species are characterized structurally by tight junctions, a low density of pinocytotic vesicles, and a moderately elevated density of mitochondria. Both alkaline phosphatase and butyryl cholinesterase were found in adult quail brain capillaries, but only alkaline phosphatase was found in adult chick brain capillaries. Aromatic amino acid decarboxylase was not found in brain capillaries of either species.In the chick embryo alkaline phsophatase appeared during the time when b‐bb matures functionally; i.e., during the third week of development. However, an elevation in mitochondrial density was not apparent until after hatching.In the quail, alkaline phosphatase and butyrl cholinesterase appeared during the last week of embryonic development. By 2 days posthatching the structural characteristics of the brain capillaries were similar to those in the

ISSN:0092-7317    

DOI:10.1002/cne.902020203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractCardiac nerves were identified physiologically and injected with horseradish peroxidase in 38 dogs. Retrogradely labeled neurons were present in the greatest number in the middle cervical ganglion, whereas fewer labeled neurons were present in the stellate ganglion. Only occasional neurons in the superior cervical ganglion were labeled, and no labeled cells were found in the T3 to T6 paravertebral ganglia or in the ganglia contralateral to the nerve injected. Following injections into specific cardiac nerves, retrograde labeling was widespread within the middle cervical ganglion, and the distributions of labeled neurons from different nerves overlapped considerably. In the middle cervical ganglion there was little or no regional grouping of cells projecting to specific cardiac nerves. Within the stellate ganglion, however, the cardiac‐sympathetic cells were clustered primarily at the cranial pole near the origin of the ventral and dorsal ansae. Mediastinal ganglia and ganglia located in cardiac nerves were frequently as heavily labeled as the ipsilateral stellate ganglion. The occurrence of heavy labeling in mediastinal and cardiac nerve ganglia indicates that these hitherto unreported ganglia play a significant role in cardiac neural regulation. These data imply that the organization of sympathetic neurons controlling the heart is much more complex than has previously been considere

ISSN:0092-7317    

DOI:10.1002/cne.902020204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThis study utilizes anterograde transport of horseradish peroxidase (HRP), Golgi staining, and electrophysiological techniques to demonstrate the origin of the parallel fibers which constitute the molecular layer overlying the intermediate nucleus of the dogfish hindbrain. The parallel fibers are shown to arise from granule cells of the auricle. The majority come from the granular area of the lower leaf of the auricles, which is termed the lateral granule cell area of the auricle. A band of parallel fibers at the ventrolateral extent of the molecular layer arises from the ipsilateral and contralateral granule cell layers of the upper leaf of the auricle. The functional continuity of the molecular layer between vestibular and lateral‐line areas may provide an additional basis for interactions between these two sense modalitie

ISSN:0092-7317    

DOI:10.1002/cne.902020205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe glial cells in abdominal ganglia of the horse leechHaemopis sanguisugawere studied by electron microscopy and analysed quantitatively to evaluate the suitability of this easily obtainable carnivorous species for physiological studies.Each abdominal ganglion contains eight giant glial cells, 12,000–14,000 small glial cells, and approximately 300 neurons. The giant glial cells constitute 44.6% and the small glial cells 6.4% of the ganglion's volume. The giant glial cells contain glycogen and bundles of filaments that are chiefly located in their periphery, close to the neurons into which they send processes. The small glial cells are frequently surrounded by the giant glial cells but also occur around neuronal perikarya and axon tracts, as well as against the basal lamina and connective tissue layers. The small glial cells contain lysosomes and sometimes form a trophospongium with the neurons. A system of extracellular channels, which is continuous with the basal lamina, indents the giant glial cells and extends around parts of the neurons. The extracellular channels contain a matrix that appears very similar to the basal lamina and to the cytoplasm in the processes of the small glial cells. Some of the extracellular channels contain collagen fibrils. Hemidesmosomes join the matrix‐filled extracellular channels to both the neurons and the giant glial cells. Ionic lanthanum has free access to the neurons and glial cells via the extracellular spaces and matrix‐filled channels. Areas of synaptic intermingling rarely contain glial cell proc

ISSN:0092-7317    

DOI:10.1002/cne.902020206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractBrain regions thought to be involved in the control of song in the zebra finch(Poephila guttata), were examined histochemically using the Karnovsky and Roots direct‐coloring method for the detection of acetylcholinesterase (AChE) and the autoradiographic method for the localization of muscarinic cholinergic receptors following injection of tritiated quinuclidinyl benzilate (3H QNB). All presently identified vocal control nuclei in both males and females contain AChE. These nuclei include Area X, magnocellular nucleus of the anterior neostriatum (MAN), nucleus interface (NIF), caudal nucleus of the hyperstriatum ventrale (HVc), intercollicular nucleus (ICo), nucleus uva, robust nucleus of the archistriatum (RA), and tracheosyringeal portion of the hypoglossal nerve nucleus (nXIIts). All nuclei except Area X contain mostly AChE‐synthesizing cell bodies. All of these nuclei contain some AChE in the neuropil, with particularly intense staining in Area X, the surrounding LPO, and the dorsomedial portion of ICo. In agreement with this description are very high concentrations of3H QNB in both Area X and the dorsomedial ICo. HVc also appears specifically labeled. Evidence from these two histological techniques suggests that efferent projections of most vocal control areas may untilize acetylcholine, and that several of the vocal control nuclei may themselves receive muscarinic cholinergic projections. In Area X, there are sex differences in AChE neuropil staining. This evidence suggests that sexually dimorphic projections to or within Area X are cholinergic or cholinocept

ISSN:0092-7317    

DOI:10.1002/cne.902020207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe number and distribution of retinal ganglion cells were examined in the burrowing frogHeleioporus eyrei.Retinae of midlarval tadpoles, animals at metamorphic climax, 2‐month postmetamorphic juveniles, and adults were flat‐mounted and stained with cresyl violet.The identity of retinal ganglion cells was established in the adult using retrograde transport of horseradish peroxidase applied to the optic nerve. Horseradish peroxidase‐filled cells, identified as neurons, had an axon hillock and contained Nissl substance within a pale‐staining cytoplasm. Glial cells, which never filled with horseradish peroxidase, had very dark nuclei and a thin film of cytoplasm lacking Nissl. The diameter of horseradish peroxidase‐filled neurons ranged from 7 to 16 m̈m. Cells identified as glia, which represented less than 1% of cells in the ganglion layer, were 3–8 m̈m in diameter. There were, however, a proportion (14%) of cells which did not fill with horseradish peroxidase. These small cells (5–7 m̈m diameter) had a similar appearance to the horseradish peroxidase‐filled cells and may be neuronal.The total number of ganglion cells rose almost 6‐fold, being approximately 61,000–83,000 for the tadpole, 100,000–118,000 at metamorphic climax, 170,000–184,000 in juveniles, and 454,000–495,000 in adults. Estimates for left and right sides in the same animal were within 1.9% for the tadpole, 1.6% at metamorphic climax, and 7.5% in the juvenile. Fiber counts were made by electron microscopy and were within 11% of ganglion cell estimates for the adult and within 5% for the remaining stages. Overall ganglion cell densities dropped from tadpoles to adults as retinal area increased 20‐fold.The topography of retinal ganglion cells changed at each stage. In the tadpole there was a radial anisotropy, the lowest density being in central retina. Anisotropy was still characteristically radial in animals at metamorphic climax but was less extreme since cell densities had dropped, particularly at the periphery. In contrast, the juvenile was beginning to form a visual streak with higher density patches appearing in nasal and temporal retina. The adult topography was similar, the highest densities still being in the nasal and temporal retina, but now a complete band of intermediate density extended across the horizontal axis of the eye. The transition of retinal ganglion cell topography to produce a visual streak after metamorphosis presumably reflects a change in life‐style from an aquatic, browsing tadpole to an animal which actively seeks its prey.The striking changes in retinal ganglion cell number and distribution provide an experimental model to study the continual development of the amphibian eye. The implications of this finding in terms of neuronal plasticity of connections formed within

ISSN:0092-7317    

DOI:10.1002/cne.902020208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractUtilizing the Golgi technique, the present study provides a structural analysis of primate marginal (lamina I) neurons in the lumbosacral spinal cord. Marginal neurons are classified on the basis of major structural differences in dendritic conformation, distribution, and specialization. Cell size and shape alone were not found to be reliable criteria. Marginal cells can be divided into four major groups. Group I (Aspiny Neurons with Thick, Blunt Dendrites) consists of neurons with relatively thick dendrites which have an abrupt, blunt termination and few spines. This heterogeneous group includes large, medium, and small neurons of various shapes. Group II cells (Large to Medium Spiny Neurons) can be subdivided into two distinct groups: Group IIA neurons, which have longitudinal spiny dendritic arbors, and Group IIB cells, which have a moderately spiny, fan‐shaped dendritic arbor which spreads across the lateral portion of the dorsal marginal zone. Both Groups A and B exhibit several types of spines. Group III (Aspiny Neurons with Thin, Tapering Dendrites) consists of small to medium size neurons which can be further divided into two groups: Group IIIA, which is characterized by oval‐ to fusiform‐shaped neurons with tortuous, fine, tapered dendrites which ramify in the dorsolateral fasciculus and the lateral funiculus, and Group IIIB, which is composed of fusiform‐, pyramidal‐ and polygonal‐shaped neurons with fine, tapering dendrites confined to lamina I. Group IV (Small Spiny Neurons) are characterized by a small fusiform‐to pyramidal‐shaped cell body and delicate longitudinal dendrites with small, short‐necked pedunculated spines. This group is subdivided into Group IVA cells, which are found within lamina I proper and Group IVB cells, which are located in the dorsolateral fasciculus and have unmyelinated axons.The present study demonstrates considerably more structural diversity within the marginal zone than has been previously reported, and offers sufficient variation to correlate with functional differences described for

ISSN:0092-7317    

DOI:10.1002/cne.902020209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractUsing Golgi preparations from adult cat and monkey, the present study describes the general arborization pattern of primary afferent collaterals to the marginal layer (lamina I) of the dorsal horn. The dorsal root origin of the Golgi‐impregnated afferents was verified in the cat by matching the structural properties of these fibers with horseradish peroxidase (HRP)‐stained primary afferents which were filled with HRP via anterograde transport through dorsal rootlets. The marginal afferents, in both the cat and the monkey, are relatively fine‐caliber fibers which emanate from the dorsolateral fasciculus of Lissauer. Superficially they form a transverse plexus of fibers which runs across the surface of the dorsal horn and is especially dense in the lateral portion of the dorsal aspect of the marginal layer where lamina I is thickest. In deeper regions of the marginal layer, marginal afferents are longitudinally oriented and have collaterals within the outer zone of lamina II. In both superficial and deep regions of the marginal layer the afferents run parallel with large numbers of marginal cell dendrites. Most marginal afferents give rise to collaterals with widely spaced, round to oval “boutons en passant” and “boutons terminaux” which are 1.5–2.0 m̈m in diameter. Structural correlation with previous physiological and anatomical studies suggests that most of these fibers are finely myelinated, A‐delta, high‐threshold mec

ISSN:0092-7317    

DOI:10.1002/cne.902020210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe projection of cat retinal ganglion cells to the thalamus was examined using the method of retrograde axonal transport of horseradish peroxidase (HRP). After the injection site was determined physiologically, HRP was applied by one of three methods: iontophoretic injection of minimal amounts, single pressure injections and multiple pressure injections.Iontophoretic injections into single laminae of the dorsal part of the lateral geniculate nucleus (LGNd) revealed that laminae A and A1 receive almost exclusively axon terminals from α and β cells. Single pressure injections elucidated the retinotopic organization of the LGNd. Multiple injections lead to HRP uptake in the whole LGNd including parts of adjacent thalamic nuclei and revealed that at least 77% of all retinal ganglion cells project to the thalamus. This pathway is made up of all α cells, all β cells and almost half of the γ cells. The thalamus receives its visual input predominantly from the ipsilateral temporal and the contralateral nasal retina; some α cells were also labeled in the contralateral temporal retina.The shape of the decussation line was analyzed and its width was found to be proportional to the average ganglion cell spacing along the dorsoventral axis of the retina. From a comparison of the retinothalamic and retinotectal pathways, an estimate of the number of cells with bifurcating axons could be given. The axons of all α cells, 10% of the β cells, and every second γ cell bifurcate; this amounts to 30% of the retinal gangli

ISSN:0092-7317    

DOI:10.1002/cne.902020211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe projection from the superior and inferior colliculi to the basilar pons in the rat was studied with the technique of orthograde transport of labeled amino acids and autoradiography. Injections restricted to the medial or lateral regions of the superior colliculus gave rise to grain labeling representing terminal fields over the ipsilateral peduncular, dorsolateral, and ventrolateral regions of the caudal basilar pons and over the dorsomedial area of the contralateral nucleus reticularis tegmenti pontis (NRTP). The pontine projection from the superior colliculus to the lateral basilar pons is topographically organized; the medial superior colliculus projects primarily to the peduncular region, wheras the lateral superior colliculus terminates chiefly in ventrolateral pontine areas. A projection from the superior colliculus to the contralateral dorsomedial pontine and medial peduncular pontine regions, a previously undescribed finding, has also been shown. Descending fibers from the inferior colliculus do not appear to terminate extensively within the basilar pons but rather course adjacent to pontine cells of the dorsolateral region in the caudal pons. Pretectal nuclei project ipsilaterally to medial and lateral nuclei in the rostral and middle basilar pons, respectively. A rostrocaudal topography exists in the tectopontine projection; the pretectum projects to rostromiddle basilar pons, the superior colliculus to more caudal pontine regions, and the inferior colliculus (although sparsely) to further caudal areas.The pontine projection pattern from the colliculi and pretectum differs from the pontine afferents from the visual cortices. The findings of this study, when compared to our results from previous investigations on the pontocerebellar projection system, suggest that the tectal inputs to certain lateral cerebellar lobules are relayed primarily through NRTP rather than the basilar pons. The collicular projections to midvermal lobules of the cerebellum appear to be mediated in part by both NRTP and lateral pontine nuclei.

ISSN:0092-7317    

DOI:10.1002/cne.902020212

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY