Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.5.2 (NQO1)
 6,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinotopic representation of the optic nerve head of the contralateral eye lies at the rostrodorsal face of the avian tectum. Since the homologous mammalian retino-collicular map shows an optic disc gap, the present anterograde HRP transport experiments were designed to detect an equivalent gap in the avian tectal retinorecipient strata. Sections tangential to the tectum at the locus of pecten representation displayed a thin, elongated, projection-less strip, crossing radially all retinorecipient laminae. Histochemical demonstration of NADH-diaphorase on similar sections showed low activity of this enzyme along an equivalent, elongated strip.
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PMID:The locus of optic nerve head representation in the chick retinotectal map lacks a retinal projection. 244 9

We have used diaphorase histochemistry to study the morphology of cells expressing nitric oxide synthase in the superficial layers of the superior colliculus of developing and adult rats. The nitric oxide synthase-positive cells showed a Golgi-like morphology and were classified according to the cell types identified by several authors using the Golgi method. The first nitric oxide synthase-positive cells appeared at postnatal day 7 and the number of stained cells increased progressively reaching a maximum at postnatal day 15. The poor staining of the dendritic tree and cell bodies in animals younger than postnatal day 15 allowed no unambiguous identification of the different cell types before that age. At postnatal day 15, based on cell soma and dendritic morphology, we have found that the following cell types express nitric oxide synthase: marginal, horizontal, narrow and wide-field vertical and stellate. In the adult, the same cell types were found to express nitric oxide synthase but the staining intensity and frequency of each cell type was different from the developing animal. Our results show that cells expressing nitric oxide synthase constitute a subpopulation of neurons in which all cell types are represented. Furthermore, our observations of nitric oxide synthase expression by collicular cells starting by the end of the first postnatal week and reaching a maximum by postnatal day 15 parallels the functional development of the retino-collicular and cortico-tectal projections and suggest that nitric oxide synthase-positive cells might be involved in this process.
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PMID:Morphology of NADPH-diaphorase-positive cells in the retinoceptive layers of the developing rat superior colliculus. 877 3

Nitric oxide (NO) is synthesized in cells of both the central and peripheral nervous system and has been implicated in several forms of synaptic plasticity. The enzyme that produces NO, nitric oxide synthase (NOS), can be visualized in the brain by the reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemistry technique (NADPH-d). We have used NADPH-d activity to detect the presence of NOS-positive cells in the developing rat superior colliculus. Our results showed that NOS is present in cells and neuropil in the developing and adult rat superior colliculus. The first NOS-positive cells appeared at postnatal day 7 and were weakly stained. The number and intensity of the NOS-positive cells increased progressively during the following days reaching a maximum at postnatal day 15. By the end of the third postnatal week, both the number and intensity of stained cells showed an adult-like pattern. The NOS-positive cells showed a Golgi-like morphology and we have found that all cell types present in the superior colliculus express the enzyme. The expression of NOS by tectal cells parallels the functional development of the retino-collicular and cortico-tectal projections and suggest that nitric oxide synthase-positive cells might be involved in this process. In this review we highlighted some of the recent descriptions of the expression of NOS in the mammalian visual system with emphasis in the superior colliculus and correlate these findings with several developmental events taking place in this structure.
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PMID:Patterns of nitric oxide synthase expression in the developing superior colliculus. 939 94

The aim of the present study was to analyze the neurochemical properties of the centrifugal visual system (CVS) of the quail using an immunohistochemical approach by testing 16 neuropeptides (angiotensin: ANG, bradykinin: BK, cholecystokinin, dynorphin, L and M-enkephalin, beta-endorphin: beta-END, galanin, alpha-neoendorphin, neurokinin A, neuropeptide Y (NPY), ocytocin, somatostatin, substance P, vasopressin, vasoactive intestinal polypeptide) and three neurotransmitters or their synthetic enzymes (choline acetyltransferase: ChAT, tyrosine hydroxylase: TH, serotonin: 5-HT and nitric oxide synthase: NOS, including the histochemical nicotinamide adenine dinucleotide phosphate diaphorase technique). For each substance, the somatic and afferent fiber and terminal labeling was analyzed within the nucleus isthmo-opticus (NIO) and the ectopic area (EA) and compared with that of retinopetal cell bodies labeled retrogradely with RITC following its intraocular injection (double-labeling procedure). The results showed that none of the centrifugal neurons were reactive to any of the substances tested. In contrast, all with the exception of ANG, BK and beta-END, labeled fibers and terminals within the EA and only four (ChAT, 5-HT, NPY and NOS) within the NIO. Possible sources of these immunoreactive fibers terminating in the NIO and EA were investigated by mapping the somatic immunolabeling of the different substances within brainstem regions previously shown by Miceli and other authors to project upon the centrifugal neurons. The data suggests that, besides the rapid retino-tecto-NIO-retinal loop, which facilitates the transfer of meaningful or more relevant information within particular portions of the visual field, the multiple afferent input which stems from various brainstem regions utilizes a wide range of neuroactive substances. Some of these afferent projections upon the centrifugal neurons appear to belong to nonspecific systems which might play a role in modulating the excitability of centrifugal neurons as a function of arousal.
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PMID:An immunohistochemical study of putative neuromodulators and transmitters in the centrifugal visual system of the quail (Coturnix japonica). 971 61

During postnatal development of the visual cortex of golden hamster, there is a transient increase in both the expression and the activity of nitric oxide synthase (NOS), which coincides temporally with the formation of ipsilateral retino-collicular and retino-geniculate projections and the functional differentiation of primary visual cortex, suggesting the involvement of NO in the maturation of the visual cortex. In the present study, an inhibitor of NOS, N-nitro-L-arginine (L-NNA) was used to block the NOS activity of newborn golden hamster, and effects on development were examined. L-NNA treatment caused an increase in mortality, and suppression of both body weight gain and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity in the early phase of treatment (before postnatal day 14, PD14). The growth of NADPH-d-positive neurons in the visual cortex was also suppressed by the treatment. In control animals, significant numbers of apoptotic neurons were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay on PD14, and this apoptosis mainly affected cells in cortical layers II and III. NOS inhibition largely rescued neurons from undergoing apoptosis, indicating that NO may serve as a signal triggering apoptosis and play a role in the maturation of the visual cortex.
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PMID:Nitric oxide synthase inhibition prevents neuronal death in the developing visual cortex. 1552 66