Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The projections of the medial terminal nucleus (MTN) of the accessory optic system have been studied in the rabbit and rat following injection of 3H-leucine or 3H-leucine/3H-proline into the MTN and the charting of the course and terminal distribution of the MTN efferents. The projections of the MTN, as demonstrated autoradiographically, have been confirmed in retrograde transport studies in which horseradish peroxidase (HRP) has been injected into nuclei shown in the autoradiographic series to contain fields of terminal axons. The following projections of the MTN have been identified in the rabbit and rat. The largest projection is to the ipsilateral nucleus of the optic tract and dorsal terminal nucleus (DTN) of the accessory optic system. Labeled axons course through the midbrain reticular formation and the superior fasiculus, posterior fibers of the accessory optic system, to reach the nucleus of the optic tract and the DTN in both rabbit and rat. Axons also run forward to traverse the lateral thalamus and to distribute to rostral portions of the nucleus of the optic tract in rat only. A second, large projection is to the contralateral dorsolateral portion of the nucleus parabrachialis pigmentosus of the ventral tegmental area together with an adjacent segment of the midbrain reticular formation. The patchy terminal field observed has been named the visual tegmental relay zone (VTRZ). This fiber projection courses within the posterior commissure and along its path to the VTRZ, provides terminals to the interstitial nucleus of Cajal and the nucleus of Darkschewitsch, both bilaterally. A third, large MTN projection distributes ipsilaterally to the deep mesencephalic nucleus, pars medialis, and the oral pontine reticular formation. Further, this projection also supplies input to the medial nucleus of the periaqueductal gray matter, bilaterally in the rabbit and rat, and in the rabbit also to the ipsilateral superior and lateral vestibular nuclei. A fourth projection crosses the midline and courses caudally to reach, contralaterally, the dorsolateral division of the basilar pontine complex and the above nuclei of the vestibular complex. A fifth projection of the MTN utilizes the medial longitudinal fasciiculus to reach the rostral medulla, in which its axons distribute ispilaterally to the dorsal cap, its ventrolateral outgrowth, and the beta nucleus of the inferior olivary complex. There is also a contralateral contingent of this projection that leaves the medial longitudinal fasciculus to innervate a small rostral segment of the contralateral dorsal cap.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pretectal and brain stem projections of the medial terminal nucleus of the accessory optic system of the rabbit and rat as studied by anterograde and retrograde neuronal tracing methods. 647 Feb 15

The connections of the middle temporal visual area (MT) and an adjoining superior temporal visual region (ST) were investigated with injections of 3H-proline and horseradish peroxidase (HRP) in adult owl monkeys. Injections in MT revealed an extensive pattern of intrinsic connections that appeared to be organized in a series of bands across MT. MT was found to project ipsilaterally to an array of visual areas including the first (V I) and second (V II) visual areas, the dorsolateral visual area (DL), and the dorso-medial visual area (DM). When injection sites and projection zones were related to previously described retinotopic maps, it was apparent that the projections of MT to these fields were largely homotopic. Other projections were to posterior parietal cortex, the dorsointermediate visual area (DI), the ventral visual area (V), and possibly the medial visual area (M). In addition, dense projections to cortex on the rostral border of MT were used to define a new subdivision of visual cortex, the superior temporal visual region (ST), as the major projection zone of MT. Callosal connections of MT were mainly to MT, with some terminations in DL and ST. Injections of 3H-proline into ST revealed a diffuse projection to largely layer I of MT, and dense projections to posterior parietal cortex, cortex in more rostral parts of the superior temporal sulcus, ventromedial inferior temporal cortex, and the region of the frontal eye fields. Callosal projections were largely to ST cortex of the other cerebral hemisphere. The results place MT and V II in distinctly different processing chains. While both MT and V II receive the major cortical outputs of V I, V II relays to DL and DL relays to subdivisions of inferior temporal cortex. In contrast, the most significant cortical target of MT appears to be to ST, which relays to posterior parietal cortex and other targets.
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PMID:Cortical connections of the middle temporal visual area (MT) and the superior temporal cortex in owl monkeys. 648 Sep 9

The major extrinsic projections to and from the visual and auditory cortical areas were examined in 4-day-old kittens using axonal transport of horseradish peroxidase (HRP) and/or tritiated proline. Six different afferent and seven different efferent systems were studied; all 13 were present by postnatal day 4 as revealed by either HRP, or autoradiography alone, or these two techniques combined. Topographical projections were found for the corticopetal pathways from the thalamus and claustrum and for the corticofugal pathways to the thalamus, claustrum, striatum, and tectum, as well as for the inter- and intrahemispheric pathways. No topographical relations were seen in projections to the cortex from the basal ganglia or the lower brainstem. The results of the present study indicate that most or all of the major extrinsic connections of the kitten's visual and auditory cortical areas are present neonatally, and that both the cells of origin and the axonal targets are arranged topographically much like those of adult cats. However, the origins of callosal projections from visual cortex are more widespread in newborn kittens than in adult cats. In addition, the laminar arrangements of the kitten's corticocortical connections differ from those of adult cats in a number of details. The results suggest that the sparing of some visual and auditory functions after neonatal lesions occurs despite the fact that the cortical areas removed have formed extrinsic connections.
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PMID:Extrinsic visual and auditory cortical connections in the 4-day-old kitten. 649 Sep 78

A restricted recovery of visual excitation occurs in the partially deafferented dorsal lateral geniculate nucleus (dLGN) of the cat after retinal lesions. In the absence of axonal growth an increase of retinogeniculate synapses at the peripheral dendrites of deafferented cells could be a possible underlying mechanism. We labeled optic tract terminals with horseradish peroxidase and [3H]proline. The size and density of labeled boutons in the vicinity of regions deafferented by chronic retinal lesions were not different from those in normal parts of the dLGN. There was no indication for synaptic proliferation as a response to partial visual deafferentiation in the adult cat dLGN.
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PMID:Recovery of function is not associated with proliferation of retinogeniculate synapses after chronic deafferentation in the dorsal lateral geniculate nucleus of the adult cat. 649 90

The centrifugal innervation of the retina was reinvestigated in albino and pigmented rats with intraocular injections of horseradish peroxidase (HRP), radioactive wheat germ agglutinin (WGA) and proline. No labeled cells were found in the brains injected with HRP and proline, except some eye muscle motoneurons in one case apparently involving orbital contamination from the injection. In the cases injected with WGA and having a survival time of at least two days cells were labeled in the lateral mesencephalic tegmentum, ventral to the parabigeminal nucleus and in the periaqueductal gray. Both these findings are most likely due to transneuronal anterograde-retrograde transport of the tracer through the superior colliculus. The results yielded no compelling evidence for the existence of a direct retinopetal pathway in the rat, which is in contrast to a recently claimed retinal projection originating from the pretectum. Special attention was paid to the labeling in the lateral mesencephalic tegmentum, an area giving rise to retinal projections in various submammalian species. This finding is discussed with regard to the possibility that also in the rat the lateral tegmentum exerts an early influence on visual input, but at the "higher" collicular level and not at the "original" retinal one.
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PMID:Is there a retinopetal system in the rat? 649 77

This study tested (1) whether blocking impulse activity in both eyes of fish with one tectum prevents the formation of ocular dominance patches, (2) whether areas receiving a high density of innervation from one eye receive a low density from the other, and (3) whether there is an electrophysiological correlate to the anatomical patches. One tectum was removed in goldfish so that the optic nerve fibers from both eyes would compete for synaptic space in the remaining tectum. The terminal arbors from the two projections initially overlapped but by 50 to 60 days segregated into ocular dominance patches, demonstrated by labeling both projections, the normal one with horseradish peroxidase and the regenerating one with tritiated proline radioautography. Alternate sections were processed for radioautography and histochemistry. All projections were drawn by "blind" observers using a camera lucida and were fully reconstructed. Both the level of patchiness within each projection and the correspondence of patches and holes between the two projections were quantified from these reconstructions. Binocular tetrodotoxin (TTX) injections from 18 to 75 days after surgery significantly reduced patchiness, as compared to controls injected with citrate-Ringers solution. When the binocular block was continued until 95 days, segregation was still significantly reduced relative to controls. These results support a hypothesis for an activity-dependent mechanism of segregation of ocular dominance patches. In controls but not TTX-blocked fish, there was a significant tendency for high density areas in one projection to receive a lower density projection from the other eye, and vice versa. However, the two projections were not entirely complementary. Survival of control fish for an additional 5 months resulted in more sharply defined patches but no increase in complementarity. Recordings of field potentials evoked by shocking either optic nerve demonstrated an electrophysiological correlate to the anatomical patches in single tectal fish. Large field potentials from one eye were generally associated with small potentials from the other eye, and vice versa. When the recording sites were marked with electrolytic lesions, there was a direct and significant correlation between the magnitude of the field potentials and the density of the anatomical ocular dominance patches.
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PMID:Activity and the formation of ocular dominance patches in dually innervated tectum of goldfish. 650 9

The development of retinal projections to the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC) has been studied in fetal and neonatal mice of the pigmented C57BL/6 strain, using the anterograde transport of tritiated proline and horseradish peroxidase (HRP). Retinal efferents are present contralaterally just beyond the chiasm at E14. By E16 they have grown into both dLGN and SC. Ipsilateral fibers are limited to the proximal optic tract at E16; their growth into dLGN and SC is delayed until E18-birth. During the first 2 postnatal days, an early population of ipsilateral fibers invades the dLGN. Most of these fibers grow in or around the medio-dorsal sector of the dLGN, i.e., the future binocular segment. Fibers are also present, but at lower densities, in the ventral half of the nucleus and thereafter become dispersed or are lost, without at any stage becoming dense. Some denser labeling is also present ipsilaterally in the outer rim of dLGN, just below the optic tract, and later disappears. On the third postnatal day, the ipsilateral fibers establish a deep and denser projection along the medial and dorsal borders of dLGN; this projection overlaps part of the crossed projection, which at this age extends to the whole nucleus. The segregation of each projection starts on the fourth postnatal day, when crossed fibers begin to disappear from the small region of uncrossed projection. This process goes on for another 4 days. During this period, the ipsilateral fibers withdraw from the deepest layer of dLGN, and their terminal density increases gradually; by the eighth postnatal day, both projections are already well separated. Dense crossed projections first appear near the surface of the SC at birth. Prior to this, retinal fibers course throughout neurons of the collicular plate and underneath the pia. The uncrossed fibers invade the SC between birth and P3. They are located preferentially in the anterior and medial aspect of the SC. Subsequently, there occurs a diminution in the laminar and tangential extent of these projections, simultaneously with an intensification of the ipsilateral input to several small, longitudinally oriented clusters located deep to the crossed projections.
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PMID:Prenatal and postnatal development of retinogeniculate and retinocollicular projections in the mouse. 652 Feb 51

Proliferative and protein synthetic activities of phagocytic cells of specific fibre tracts of the periodontium of C57Bl mice were employing autoradiographic techniques; these were combined with a histochemical technique for horseradish peroxidase (HRP) as a marker for phagocytic activity. Animals were injected either with [3H]thymidine as a marker for proliferative activity, or with [3H]proline as a marker for protein synthetic activity prior to HRP injection. Blocks from the maxillae of experimental and control animals were fixed, decalcified, and sectioned at 50 micrometers. These were incubated with HRP localization media, dehydrated and flat embedded in Epon 812 wafers. The entire length of the periodontium, including adjacent tooth and bone, were selectively cut from the wafers, mounted on epoxy blocks and serially sectioned at 2 micrometers. Slides containing these sections were then dipped in NTB-3 nuclear track emulsion, and after appropriate exposure times, were developed and post-stained. Sections were examined microscopically, employing an ocular grid, and phagocytic cells within each area examined were delineated as either 'fibroblast-like' (FL cells) or 'endothelial/macrophage-like' (EML cells) according to criteria such as morphology, location, orientation and proximity to a vascular channel. They were then subclassified as labelled or unlabelled with respect to the autoradiographic markers. The thymidine labelling index obtained for non-phagocytic FL cells was 3.09%; this was more than twice that for phagocytic FL cells (1.35%). Similarly phagocytic FL cells in all regions studied incorporated less than half as much [3H]proline as did their non-phagocytic counterparts. This was determined by silver grain counts over HRP-stained and unstained cells using a matched pair system. In addition, the variation of the relative number of phagocytic FL cells in specific fibre tracts suggested a relationship to functional demand. The distribution of these cells was closely related to experimentally determined rates of protein turnover. Phagocytic FL cells have a markedly reduced proliferative rate and synthesize proline-containing proteins at a reduced rate. This may reflect protein production primarily for the purpose of cell maintenance. These findings are consistent with the presence of subpopulations of fibroblasts (or fibrocytes) developmentally or functionally modified for phagocytosis; alternatively, this could signify modulation of fibroblasts from primarily biosynthetic activities to degradative functions in response to varying microenvironmental conditions.
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PMID:Autoradiographic and cytochemical studies of phagocytic cells in selected fibre tracts of the mouse periodontium. 664 15

Corpus callosum connections of parietal and motor cortex were studied in New World owl monkeys (Aotus trivirgatus) and Old World macaque monkeys (Macaca fascicularis) after multiple injections of 3H-proline and horseradish peroxidase, HRP, into one cerebral hemisphere, and extensive microelectrode mapping of architectonic Areas 3b, 1, and 2 of the other hemisphere. Results were obtained both from parasagittal brain sections cut orthogonal to the brain surface and from sections from flattened brains cut parallel to the brain surface. Cortical fields varied in density of callosal connections, and the density of connections varied according to body part within sensory representations. Thus, Area 3b had few, Area 1 had more, and Area 2 had relatively dense callosal connections. Within each of these fields, connections were much less dense for the representations of the glabrous hand and foot and much more dense for the representations of the face and trunk. For the representation of the hand, retrogradely labeled cells were extremely sparse in Area 3b, moderately sparse in Area 1, and moderate in Area 2. There were less dense callosal connections in the hand representations of Areas 3b, 1, and 2 in macaque as compared to owl monkeys. Label in posterior parietal cortex was uneven with zones of extremely dense connections. A large region of very dense callosal connections was noted in motor cortex just medial to the probable location of the hand representation. In all regions, callosally projecting cells appeared to be more broadly distributed than callosal terminations. In no region was the discontinuous arrangement of callosal connections obviously organized into an extensive pattern of mediolateral or rostrocaudal bands or strips.
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PMID:The relation of corpus callosum connections to architectonic fields and body surface maps in sensorimotor cortex of new and old world monkeys. 664 13

We have analyzed the connections between the sensory trigeminal nuclei and two major sensorimotor areas (i.e., the superior colliculus and crura I and II of the cerebellar cortex) in which tactile input from peri-oral and other facial regions is a prominent feature. Following injections of horseradish peroxidase into the superior colliculus, retrogradely labeled cells occupy the ventral one-third of the contralateral principal sensory and spinal trigeminal nucleus; trigeminocollicular neurons are especially numerous within the subnucleus interpolaris (Svi). Injections of either 3H-proline or horseradish peroxidase (HRP) into the Svi reveal that trigeminocollicular axons reach the rostral two-thirds to three-quarters of the contralateral superior colliculus, where they distribute in a nonuniform, patchy manner within layers IV-VI. In addition to demonstrating the trigeminocollicular projection, anterograde and retrograde transport studies of the Svi also reveal a trigeminoolivary projection which terminates primarily within the contralateral rostral dorsal accessory (DAO) and adjacent principal (PO) olives; some of the Svi neurons innervate both the superior colliculus and the DAO-PO via axon collaterals. Data from a final set of retrograde tracing experiments show that the trigeminorecipient zone of the DAO-PO contains neurons which project to crura I and/or II of the cerebellar cortex. Of the various submodalities conveyed by the trigeminal system, it is likely that the trigeminal connections we have demonstrated are carrying tactile information. This is indicated by the fact that responses to tactile stimulation of the face have been reported for cells in (1) the deeper collicular layers, (2) the trigeminorecipient zone of the DAO-PO, and (3) cerebellar targets of this zone, crura I and II. All data are discussed in the context of the anatomical and physiological literature.
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PMID:Studies of the principal sensory and spinal trigeminal nuclei of the rat: projections to the superior colliculus, inferior olive, and cerebellum. 664 23


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