Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The connections between the nucleus isthmi and the tectum in the frog have been determined by several anatomical techniques: iontophoresis of horseradish peroxidase into the tectum, iontophoresis of 3H-porline into the nucleus isthmi and the tectum, and Fink-Heimer degeneration staining after lesions of the nucleus isthmi. The results show that the nucleus isthmi projects bilaterally to the tectal lobes. The ipsilateral isthmio-tectal fibers are distributed in the superficial layers of the tectum, coincident with the retionotectal terminals. The contralateral isthmio-tectal fibers travel anteriorly adjacent to the lateral optic tract and cross the midline in the supraoptic ventral decussation, where they turn dorsally and caudally; upon reaching the tectum, the fibers end in two discrete layers, layers 8 and A of Potter. The tectum projects to the ipsilateral nucleus isthmi and there is a reciprocal topographic relationship between the two structures. Thus, a retino-tecto-isthmio-tectal route exists which may contribute to the indirect ipsilateral retinotectal projection which is observed electrophysiologically. The connections between the nucleus isthmi and the tectum in the frog are strinkingly similar to the connections between the parabigeminal nucleus and the superior colliculus of mammals.
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PMID:Topographic projections between the nucleus isthmi and the tectum of the frog Rana pipiens. 30 27

In order to examine the pattern of the retino-pulvinar projection in the cat, the existence of which has been recently demonstrated using autoradiographic fiber tracing technique, a small amount of horseradish peroxidase (HRP) was injected into the lateral part of the pulvinar nucleus at various rostocaudal levels. The retrogradely labeled ganglion cells were analyzed in terms of their topographical location and cell size, as seen inretinal whole mounts. The results were compared with those obtained following injections into the lateral geniculate nucleus. Retrogradely labeled cells were found in the retina bilaterally after injections of HRP into the pulvinar nucleus. Pulvinar injections produced labeling of retinal cells in the nasal half of the retina contralaterally, and in the temporal half ipsilaterally. The labeled cells were diffusely distributed in a retinotopically organized fashion. The representation of the area centralis in the retino-pulvinar projection is displaced rostrally as compared with the retino-geniculate projection. All labeled cells after pulvinar injections were medium to small size and no large cells were encountered.
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PMID:Topographical origin and ganglion cell type of the retino-pulvinar projection in the cat. 38 7

Several genetically distinct color phases of mink, which all show an abnormal reduction of pigment in the retinal pigment epithelium and which also show abnormalities of the retinofugal pathways, have been studied. Autoradiographic methods have been used to demonstrate the retino-geniculate pathways, and retrograde degeneration or the retrograde transport of horseradish peroxidase has been used for the geniculo-cortical pathways. The retino-geniculate abnormality is mild in some of the color phases and extremely severe in others, but within any one color phase the variability is relatively low. Although the severity of the abnormality varies between color phases, a rather specific pattern of abnormal geniculate innervation is recognizable for mink in general and this is distinct from that found in Siamese cats. In the abnormal mink the size of geniculate lamina A1 is reduced and there is an abnormal crossed input going to the intermediate sectors of this reduced layer. Layer C1 also receives an abnormal crossed input, but this is more variable than that going to A1 and there appears to be little correspondence, retinotopically, between the normal inputs to layers A1 and C1. In some of the abnormal mink there are interruptions within the cytoarchitectionically definable layer A1, and opposite these gaps reduplications of layer A are commonly seen, as though there is an intrinsic geniculate mechanism for generating the characteristic multilaminar geniculate structure. However, there are also numerous examples of fusions between layers receiving afferents from the same eye, and these demonstrate that the development of geniculate lamination must also be under the influence of the retinal inputs. The geniculo-cortical pathway shows a normal topography in most of the mink. Abnormal geniculo-cortical projections, comparable to the "Boston" pattern of Siamese cats are extremely rare, and their occurrence could not be correlated with the severity of the retino-geniculate abnormality or with the laminar pattern in the lateral geniculate nucleus. We suggest that the development of one or the other pattern of geniculo-cortical projection may depend upon the relative timing of the two mechanisms that produce the geniculate lamination.
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PMID:Abnormal retino-geniculate and geniculo-cortical pathways in several genetically distinct color phases of the mink (Mustela vison). 44 75

A cerebello-pulvino-cortical and a retino-pulvino-cortical pathways were revealed in the cat by means of the horseradish peroxidase (HRP) method. The sites of termination of the cerebellofugal and retinofugal fibers in the pulvinar nucleus (Pul) were visualized by the use of the anterograde transport of HRP. The cerebello-pulvinar fibers were found to arise mainly from the parvicellular region of the lateral cerebellar nucleus and to terminate contralaterally in a narrow area at the extreme dorsolateral edge of the Pul at the level of the stereotaxic frontal plane A-7.0. The area of terminal ramification of retino-pulvinar fibers was seen as a thin sheet lying at the extreme lateral edge of the Pul through most of the rostrocaudal extent of the Pul, bilaterally with contralateral predominance. The cerebellorecipient area in the Pul did not seem to overlap with the retinorecipient Pul area; the former appeared to be contiguous ventrolaterally to the latter. The cerebellorecipient and retinorecipient Pul areas were also observed to be connected reciprocally with the cerebral cortical areas; the former was connected with the most posterior part of the area 20, and the latter with the area 19.
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PMID:A cerebello-pulvino-cortical and a retino-pulvino-cortical pathways in the cat as revealed by the use of the anterograde and retrograde transport of horseradish peroxidase. 48 83

In our horseradish peroxidase (HRP) study of the afferents to the medullary raphe nuclei in the cat, HRP uptake by damaged axons en route to the inferior olive (IO) was thought to be responsible for retrograde labelling of specific midbrain nuclei. To control for such indirect labelling, HRP was injected iontophoretically into the inferior olive. The location of retrogradely labelled neurons was related to the specific locus of HRP injection within the IO. Injection of HRP into the caudal dorsal accessory olive resulted in dense neuronal labelling in the ipsilateral caudal pole of the posterior pretectal nucleus (PPN). There was no labelling of the nucleus of Darkschevitch (Dk), interstitial nucleus of Cajal (ICA) or Edinger-Westphal nucleus (EW). In contrast, an injection focussed more rostrally, into the rostral, dorsal accessory, the medial accessory and the principal olive, produced dense labelling of Dk, ICA and EW; there was much less PPN labelling. It is concluded that labelling of Dk and PPN after HRP injections rostral to the IO, is due, at least in part, to uptake of HRP by damaged medial longitudinal fasciculus axons en route to the inferior olive. The direct PPN-inferior olivary projection provides a potential disynaptic retino-cerebellar connection, which may be involved in rapidly timed eye-body coordinate movements.
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PMID:The posterior pretectal nucleus: evidence for a direct projection to the inferior olive of the cat. 53 Apr 60

In order to demonstrate the central projections of the different ganglion cell classes in the albino rat retina horseradish-peroxidase was injected into the superior colliculus (CS) and into the lateral geniculate nucleus (Cgl). The study presents the following results: a) Injection into the CS: Labelled cells are only in the contralateral retina. Topistically, the retino-collicular projection is in good agreement with the findings of physiological methods. The nasal half of the retina projects mainly to the posterior part and the superior half to the lataral part of the CS. Taking into consideration our cell-size-classification among 500 labelled cells we found 63% of the small group (7...10 micrometer soma diameter), 35% of the medium-sized (11...14 micrometer) and only 2% of the large group (15...23 micrometer). The small cells (W-system)project mainly, but not alone and not exclusively to the CS. b) Injection into the Cgl: In the ipsilateral retina we found a few labelled cells in the superior, temporal region. Contralateral--as after CS-injection--only half of ganglion cells is labelled. The quantitative analysis of 500 labelled cells indicates: 32% belong to hte small group, 51% to the medium-sized and 17% to the large group. There are fibers of all three classes, but in the majority those of the medium-sized class terminating in the Cgl. It is discussed whether these results allow a comparison of the size classes with the W-, X- and Y-system. Our findings show that there is no clear agreement between cell-size and projection site as demonstrated in cats. There is a large overlapping of the cell classes with respect to their central projection. We found that with increasing soma-diameter the ganglion cells project more and more to the Cgl. It is known that in the Golgi-picture cells with different soma diameter are of the same neuron type. Therefore, a morphological comparison of the ganglion cells of the rat with the W-, X- and Y-system is only ingenious taking into consideration also the dendritic structure.
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PMID:[Projection of different ganglion cell classes in the albino rat retina. A study using horseradish peroxidase]. 74 83

In this study, we crushed one optic nerve in the frog Litoria (Hyla) moorei and at intervals thereafter anterogradely labelled optic axons with horseradish peroxidase (HRP). For one series, HRP was applied between the eye and the crush site and in a second series between the crush site and the chiasm. A tectal projection of regenerating axons was seen in both series but, in addition, up to 12 weeks post-crush, the second series displayed an additional projection. Its appearance matched that of the disconnected, but persisting, optic axon terminals which are found after enucleation or optic nerve ligation. We conclude that, in the frog, many disconnected optic axons persist throughout the period of optic nerve regeneration and of restoration of an orderly retino-tectal map.
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PMID:Disconnected optic axons persist in the visual pathway during regeneration of the retino-tectal projection in the frog. 138 2

Naturally occurring ganglion cell death has been attributed to competitive interactions among axons at their targets during development of the retinofugal pathways. The present study is concerned with the hypothesis that interocular interactions leading to ganglion cell death are restricted to binocularly conjugate terminals in the optic nuclei. We tested this hypothesis in newborn rats by making localized retinal lesions, which denervate a restricted portion of the contralateral optic targets. When these rats reached adulthood, the ipsilaterally projecting ganglion cells of the intact eye were then studied following retrograde labeling with horseradish peroxidase. Results were compared with those from a normal, control group and from rats that had one eye removed on the day of birth. In those retinal loci binocularly conjugate to the lesion in the opposite eye, no localized cell rescue could be found among the ipsilaterally projecting ganglion cells. The same retinal loci, however, showed clear cell rescue after contralateral enucleation. Independent, anterograde, studies of the ipsilateral retino-collicular projection verified that lesions of equivalent size to those used in the retrograde study reliably create aberrant expanded uncrossed terminal fields. The present data suggest that the interocular interactions involved in the diminished ganglion cell loss which follows monocular enucleation are not dependent on topographically specific binocular matching. The phenomena of naturally occurring cell loss and of retinotopically specific interocular interactions may therefore be independent during normal development.
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PMID:Cell death and interocular interactions among retinofugal axons: lack of binocularly matched specificity. 170 41

Retrograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L), fluorogold, fast blue, rhodamine labelled microspheres, and horseradish peroxidase (HRP) was employed to study the distribution, laminar location within the optic tectum, and morphology of tectal cells projecting upon the isthmo-optic nucleus (ION) and the nucleus isthmi, pars parvocellularis (Ipc), in the pigeon and chick. Following injections into the ION, all retrograde markers labelled tecto-ION neurons and their dendrites in the ipsilateral tectum. The cells were located within a relatively narrow band at the border between layers 9 and 10 of the stratum griseum et fibrosum superficiale (SGFS). Retrogradely labelled neuronal somata were different in both dendritic branching and shape; however, tecto-ION neurons generally possessed non-spiny radially oriented and multi-branched dendrites. The apical processes extended into the retino-recipient layers (2-7) of the SGFS and basal dendrites extended into layers 12-14 of the SGFS. Positive neuronal somata were observed throughout the rostro-caudal extent of the optic tectum. The average distance between adjacent tecto-ION neurons varied from one region to another. Specifically, retrogradely labelled cells were more numerous in the caudal, lateral, and ventral tectum, and less numerous at rostro-dorsal levels. Approximately 12,000 tecto-ION neurons were labelled within the ipsilateral optic tectum following either PHA-L or fluorescent dye injections. While the regional distribution of tecto-Ipc neurons was not examined, the morphology indicated that the cells had a single radially oriented dendritic process. Therefore, the apical dendrites are more restricted than those of tecto-ION cells. Moreover, the dendrites were spiny and arborized within layers 3, 5, and 9 of the ipsilateral optic tectum. The axon of tecto-Ipc cells arise from the apical process as a shepherd's crook and descend into the deep layers of the optic tectum. These results indicate that 1) tecto-ION and tecto-Ipc neurons are possibly monosynaptically activated by retinal input, 2) tecto-ION neurons are heterogeneous in morphology, and 3) there is a differential distribution of the tecto-ION neurons throughout the rostro-caudal extent of the optic tectum, suggesting a greater representation of the caudo-ventral portion of the optic tectum within the ION. The discussion primarily concerns the organization of the retino-tecto-ION-retinal circuit in light of the distribution and morphology of tecto-ION neurons within the optic tectum.
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PMID:Distribution, laminar location, and morphology of tectal neurons projecting to the isthmo-optic nucleus and the nucleus isthmi, pars parvocellularis in the pigeon (Columba livia) and chick (Gallus domesticus): a retrograde labelling study. 170 56

Previous transneuronal anterograde tracing studies have shown that the retino-thalamic pathway to the posteromedial lateral suprasylvian (PMLS) visual area of cortex is heavier than normal in adult cats that received neonatal damage to visual cortical areas 17, 18, and 19. In contrast, the strength of this projection does not appear to differ from that in normal animals in cats that experienced visual cortex damage as adults. In the present study, we used retrograde tracing methods to identify the thalamic cells that project to the PMLS cortex in adult cats that had received a lesion of visual cortex during infancy or adulthood. In five kittens, a unilateral visual cortex lesion was made on the day of birth, and horseradish peroxidase (HRP) was injected into the PMLS cortex of both hemispheres when the animals were 10.5 to 13 months old. For comparison, HRP was injected bilaterally into the PMLS cortex of three cats 6.5 to 13.5 months after they received a similar unilateral visual cortex lesion as adults. In cats with a neonatal lesion, retrograde labeling was found in the large neurons that survive in the otherwise degenerated layers A and A1 of the lateral geniculate nucleus (LGN) ipsilateral to the lesion. Retrograde labeling of A-layer neurons was not seen in the undamaged hemisphere of these animals or in either hemisphere of animals that had received a lesion as adults. As in normal adult cats, retrograde labeling also was present in the C layers of the LGN, the medial interlaminar nucleus, the posterior nucleus of Rioch, the lateral posterior nucleus, and the pulvinar nucleus ipsilateral to a neonatal or adult lesion. Quantitative estimates indicate that the number of labeled cells is much larger than normal in the C layers of the LGN ipsilateral to a neonatal visual cortex lesion. Thus the results indicate that the heavier than normal projection from the thalamus to PMLS cortex that exists in adult cats after neonatal visual cortex damage arises, at least in part, from surviving LGN neurons in the A and C layers of the LGN. Although several thalamic nuclei, as well as the C layers of the LGN, continue to project to PMLS cortex after an adult visual cortex lesion, these projections appear not to be affected significantly by the lesion.
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PMID:Thalamic projections to the lateral suprasylvian visual area in cats with neonatal or adult visual cortex damage. 172 8


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