Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to generate the molecular probes needed to investigate the seemingly coordinate expression of carbonic anhydrase (CA I) and beta-globin within erythrocytes during human development, CA I-containing polyribosomes have been isolated from rabbit reticulocytes by reaction with purified antibodies to CA I followed by immunoadsorption of immune complexes with formalin-fixed protein A-bearing bacteria. In the course of such isolation, a series of maneuvers were seen to have a markedly favorable influence on the level of purity attained. These maneuvers include the use of 5 mg/ml of heparin concentrations to attenuate nonspecific binding and entrapment of unwanted polyribosomes, the addition of 200 units/ml of placental ribonuclease inhibitor to augment recovery in reactions which by test already appeared RNase-free, and the preadsorption of polyribosomes with formalin-fixed bacteria prior to immunological reaction so as to remove a subset of polyribosomes seemingly predisposed to nonspecific binding. In the absence of all of the maneuvers, attained purity was no greater than a few per cent. When all were employed, CA I-mRNA derived from immunopurified polyribosomes was recovered with more than 80% purity and 20% yield, as evident from both immunoassays and electrophoresis of its cell-free products.
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PMID:Adjuvants to immunological methods for mRNA purification. Application to the isolation of mRNA for carbonic anhydrase I from rabbit reticulocytes. 640 29

Nitric oxide can act as a neurotransmitter and a retrograde modulator of synaptic transmission, but uncontrolled nitric oxide synthase activity has been associated with neural degeneration. Although earlier studies using immunohistochemistry, in situ hybridization, and NADPH-diaphorase staining had suggested that nitric oxide synthase is not expressed in the CA1 neurons of the hippocampus, we have recently demonstrated that NADPH-diaphorase activity can be detected in CA1 neurons of the hippocampus. To confirm that this diaphorase activity reflects nitric oxide synthase, we have developed a more sensitive in situ hybridization procedure, and an RNase protection assay to detect message for constitutive nitric oxide synthase, the form constitutively expressed in many neurons. Message for constitutive nitric oxide synthase is expressed in the hippocampus, and it is localized to neural cell layers CA1, CA3, the dentate gyrus and some displaced neurons, but not to CA2. Expression of constitutive nitric oxide synthase message in the CA1 region was lost when pyramidal neurons died due to transient forebrain ischemia, supporting the conclusion that CA1 pyramidal cells express constitutive nitric oxide synthase. Although constitutive nitric oxide synthase message is strongly expressed in CA3 and the dentate gyrus, there is little diaphorase activity in these cells, suggesting that there may be post-transcriptional controls that limit constitutive nitric oxide synthase expression in some cells. Message for constitutive nitric oxide synthase is also present in a number of other regions, including the amygdala, several hypothalamic nuclei, the cerebellum, the olfactory bulb, two distinct regions of the perirhinal cortex, the subthalamic nuclei, a neuronal layer in the retrosplenial granular cortex, the lateral geniculate nucleus, the presubiculum, the inferior colliculus, the superior colliculus, the pedunculopontine tegmental nucleus, and scattered individual neurons in the cortex, hippocampus and brainstem. These studies support a role for nitric oxide in multiple regions of the central nervous system. In particular, nitric oxide synthase, the enzyme responsible for the synthesis of nitric oxide, is expressed in the CA1 region of the hippocampus, where there is evidence that nitric oxide may play a major role in long-term potentiation. CA1 hippocampal neurons are an example of a population of neurons that express constitutive nitric oxide synthase but are very sensitive to excitotoxicity and ischemic insults.
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PMID:Expression of the neural form of nitric oxide synthase by CA1 hippocampal neurons and other central nervous system neurons. 753 83

We previously reported transiently elevated ER protein levels in the postnatal rat hippocampus suggesting that this brain region may be sensitive to estrogenic trophic and organizational influences during a 'critical period' of sexual differentiation. In order to examine whether alterations in ER gene expression underlie the ontogenetic pattern of the hippocampal ER, we examined ER mRNA levels over the early postnatal period and in adult rats. This was accomplished by both a highly quantitative RNase protection assay and in situ hybridization histochemistry. Hippocampal ER mRNA levels increased significantly (P < 0.005) between birth and postnatal day (PDN) 4 when peak concentrations were found and then declined by PND-10. Adult male hippocampal ER mRNA values were similar to those found in newborn and PND-10 animals but were significantly less (P < 0.05) than those observed on PND-4. Results from the in situ hybridization experiments correlated well with those from the RNase protection analysis. High levels of ER mRNA were present in the CA3 pyramidal layer with somewhat lower labeling intensities present in CA1 and the dentate gyrus of the PND-4 animal. In contrast, adult male animals demonstrated little hybridization throughout the hippocampus. Thus, the temporal pattern in ER mRNA levels in the hippocampus found in the present study correlates well with our previous developmental profile of the ER protein. These findings suggest that the ontogeny of ER in the hippocampus is regulated by alterations in ER gene expression in specific neuronal populations.
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PMID:Estrogen receptor mRNA alterations in the developing rat hippocampus. 760 32

The actions of androgens in both peripheral and central tissues are linked in part to their ability to specifically bind and activate androgen receptors (ARs). ARs have been well studied in the rat hypothalamus and peripheral reproductive tissues, where they are directly involved in endocrine feedback mechanisms and reproduction. Previous studies revealed relatively high levels of AR and AR messenger RNA (mRNA) in the rat hippocampus; however, the action of androgen in this brain region remains unclear. To begin to address this issue, we used a multidisciplinary approach to quantitate hippocampal AR and AR mRNA levels and investigate their regulation after various hormonal manipulations. In vitro binding assays revealed a single, saturable, high affinity binding site for androgen in hippocampal cytosols. The expression of AR mRNA in the intact adult male rat hypothalamus and hippocampus was demonstrated using reverse transcription-polymerase chain reaction and quantified using a ribonuclease protection assay. Comparable levels of AR mRNA were found in the hippocampus and hypothalamus. In addition, in situ hybridization analysis revealed a unique distribution of AR mRNA in the hippocampus. AR mRNA was found predominately in the CA1 pyramidal cells, which form the major signal output of the hippocampal trisynaptic circuit. Reverse transcription-polymerase chain reaction of total RNA from microdissected hippocampal regions confirmed this distribution. Ribonuclease protection assay demonstrated a significant decrease in the AR mRNA content of the hippocampus in animals killed 4 days after castration or in intact rats after four daily injections of the AR antagonist, flutamide (15 mg/animal), compared to that in intact controls (P < 0.01). In contrast, a 35% increase (P < 0.05) in the hippocampal AR mRNA content was found in old (22-month-old) compared to young (5-month-old) male rats. In both cases, [3H]dihydrotestosterone binding to the cytosolic preparation did not parallel the changes observed in the AR mRNA content. Taken together, these data demonstrate that hippocampal cells containing AR can respond to circulating androgen to alter AR gene expression. Furthermore, AR mRNA autoregulation appears to be both age and tissue specific and does not directly follow the regulatory patterns described for other steroid hormone receptors found in the hippocampus.
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PMID:Distribution and hormonal regulation of androgen receptor (AR) and AR messenger ribonucleic acid in the rat hippocampus. 762 54

The distribution of rat vasoactive intestinal peptide2 (VIP2) receptor messenger RNA in the brain and the pituitary gland was examined by in situ hybridization and by ribonuclease protection assay. labelled cells were found chiefly in the suprachiasmatic nucleus, the central nucleus of the amygdala and the thalamus (the lateral geniculate nucleus, and the paraventricular, mediodorsal and ventral nuclei of the thalamus). The distribution of the VIP2 receptor overlaps only in part with that of the VIP1 receptor, for example in the hippocampus, where VIP2 receptor messenger RNA was found in the pyramidal cells of the CA1-CA3 subfields and in the granule cells of the dentate gyrus. Small numbers of neurons containing high concentrations of VIP2 receptor messenger RNA were present in the brainstem in the principal sensory trigeminal nucleus and in the substantia gelatinosa of the spinal cord, suggesting a role for the VIP2 receptor in the processing of sensory information. The presence of the VIP2 receptor in the suprachiasmatic nucleus suggests that it is this receptor subtype which is involved in the control of circadian rhythms.
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PMID:The distribution of vasoactive intestinal peptide2 receptor messenger RNA in the rat brain and pituitary gland as assessed by in situ hybridization. 767 76

Both RNase protection assay and in situ hybridization were used to investigate the effect of intraperitoneal injection of kainate on the messenger RNA levels for basic fibroblast growth factor in the rat central nervous system. Limbic motor seizures were produced by kainate injection and this event was followed by a significant elevation of basic fibroblast growth factor gene expression in rat hippocampus and striatum 6 h after the convulsant injection. The increase in hippocampus was maximal at 24 h and it was delayed with respect to nerve growth factor induction, which peaked 3 h after kainate injection. Animals that suffered prolonged seizure activity also showed a significant elevation of basic fibroblast growth factor gene expression four and 14 days after kainate, when no changes in nerve growth factor gene expression were observed. We show that, within the hippocampus, the increase of basic fibroblast growth factor messenger RNA was localized in dentate gyrus and the CA1 layer 6 and 24 h after kainate injection. Long-term effects on its gene expression were measurable only in the CA1 hippocampal subfield, where major cell damage and astrocytosis have been reported to occur following kainate-induced seizure activity [Ben-Ari Y. et al. (1981) Neuroscience 7, 1361-1391; Lothman E. W. and Collins R. C. (1981) Brain Res. 218, 299-318; Schwob J. E. et al. (1980) Neuroscience 5, 991-1014]. Indeed, the animals which displayed elevated messenger RNA levels for basic fibroblast growth factor four and 14 days after kainate injection showed a marked induction of messenger RNA expression for the astroglial marker glial fibrillary acidic protein. These results indicate that the glutamate analogue kainate produces short- and long-term increases of basic fibroblast growth factor messenger RNA expression with a specific anatomical pattern. Therefore, the gene expression for this neurotrophic factor is probably regulated by neuronal activity at early points in time, whereas the induction observed at later time points is related to adaptive mechanisms taking place following kainate-induced neuronal degeneration.
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PMID:Short- and long-term induction of basic fibroblast growth factor gene expression in rat central nervous system following kainate injection. 819 Feb 72

There is considerable evidence that GABAergic neurons play an important role in the regulation of gonadotropin-releasing hormone (GnRH) secretion, and that these neurons may mediate the feedback actions of gonadal steroids on GnRH neurons. The aim of the present study was to investigate whether endogenous changes in ovarian steroid secretion during the estrous cycle influenced GABAergic neuronal activity in the preoptic region of the hypothalamus, and in other steroid-sensitive brain regions. Intact, adult female rats were sacrificed at various times during the days of metestrus or proestrus. GABAergic neuronal activity was estimated by measuring the rate of accumulation of GABA in microdissected brain regions after pharmacological inhibition of GABA degradation. Concentrations of mRNA for both forms of glutamic acid decarboxylase (GAD65 and GAD67) were quantified in microdissected brain regions by a microlysate ribonuclease protection assay. In the diagonal band of Broca at the level of the organum vasculosum of the lamina terminalis (DBB(ovlt)), GABAergic neuronal activity was significantly reduced during the afternoon of proestrus compared with the morning of either proestrus or metestrus. In the lateral septal nucleus, GABAergic neuronal activity was significantly increased in the afternoon of proestrus compared with the morning. There were no significant effects of time of day or day of estrous cycle in the medial preoptic nucleus, median eminence, ventromedial nucleus, suprachiasmatic nucleus, medial septal nucleus, hippocampus (CA1 region), or cingulate cortex. In the DBB(ovlt), mRNA levels for both GAD65 and GAD67 were significantly reduced in the afternoon of proestrus compared with the afternoon of metestrus. By contrast, there was no change in GAD65 and GAD67 mRNA levels in the cingulate cortex at any of the times examined. These results demonstrate that GABAergic neuronal activity, and mRNA levels for both GAD65 and GAD67, are reduced in the DBB(ovlt) during the afternoon of proestrus. These results support the hypothesis that decreased GABAergic neuronal activity in this region plays a major permissive role in the generation and maintenance of the estrogen-induced LH surge.
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PMID:GABAergic neuronal activity and mRNA levels for both forms of glutamic acid decarboxylase (GAD65 and GAD67) are reduced in the diagonal band of Broca during the afternoon of proestrus. 889 Dec 47

Living hippocampal slices from Wistar rats were used to study the dynamics of changes in population electrical responses in field CA1 to electrical stimulation of Shaffer collaterals during the development of ischemia (imposed by exclusion of oxygen and glucose from the perfusion solution). These studies showed that during ischemia, addition of ribonuclease (a blocker of protein synthesis) to the perfusion solution resulted in a significantly smaller increase in the latent period of the response and slowed the onset of the reduction in the amplitude of the evoked potential, and promoted faster recovery of the response after the ischemia session ended. It is suggested that the reduction in protein synthesis due to ribonuclease preserved energy reserves in the nerve tissue, which in turn promoted more complete recovery of neuron function in the post-ischemic period.
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PMID:Ribonuclease improves the state of hippocampal sections in the post-ischemic period. 976 5

Brain-derived neurotrophic factor (BDNF) and its receptor, TrkB, regulate synaptic functions in the hippocampus of the adult rodent. In previous studies, in situ hybridization methods have been used to evaluate regional differences in BDNF and trkB mRNA expression levels in hippocampal subregions. However, these studies have failed to reach consensus regarding the regional differences in the mRNA expression levels. In the present study, we quantitated mRNA expression levels using two different methods, ribonuclease protection assays and a quantitative reverse-transcription polymerase chain reaction technique, in four hippocampal subregions: the entorhinal cortex, dentate gyrus (DG), CA3 and CA1. These two methods yielded the same results. We found that BDNF and trkB mRNA expression levels did not covary in the four subregions. BDNF and full length trkB (trkB FL) mRNA in the entorhinal cortex and the DG show contrasting expression patterns. The expression level of BDNF mRNA was highest in the DG among the hippocampal subregions and low in the entorhinal cortex and the CA1, whereas the trkB FL mRNA expression level was highest in the entorhinal cortex, low in the DG and lowest in the CA3. These results suggest regional differences in BDNF/TrkB signaling for maintenance and modifiability of neuronal connections in the hippocampal formation.
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PMID:Highest trkB mRNA expression in the entorhinal cortex among hippocampal subregions in the adult rat: contrasting pattern with BDNF mRNA expression. 981 29

There is growing evidence that alterations in calcium (Ca2+) homeostasis may play a role in processes of brain aging and neurodegeneration. There also is evidence that some of the altered Ca2+ homeostasis in hippocampal neurons may arise from an increased density of L-type voltage sensitive Ca2+ channels (L-VSCC). In the present studies, we tested the possibility that previously observed increases in functional L-VSCC with aging might be related to up-regulated gene/mRNA expression for Ca2+ channel subunits. A significant aging-related increase in mRNA content for the alpha1D subunit of the L-type VSCC was observed in hippocampus of aged F344 rats (25 months old) relative to young (4 months old) and middle-aged animals (13 months old), as assessed by both in situ hybridization analyses (densitometry and grain density) and ribonuclease protection assay (RPA). In RPA analyses, the alpha1C subunit mRNA also showed a significant increase in 25-month-old rats. No age changes were seen in mRNA for the beta1b subunit of VSCC or for GAPDH, a standard control. The clearest increases in alpha1D mRNA expression were observed in subfield CA1, with little or no change seen in dentate gyrus. Although these results alone do not demonstrate that mRNA/gene expression changes contribute directly to changes in functional Ca2+ channels, they clearly fulfill an important prediction of that hypothesis. Therefore, these studies may have important implications for the role of gene expression in aging-dependent alterations in brain Ca2+ homeostasis.
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PMID:Up-regulation of alpha1D Ca2+ channel subunit mRNA expression in the hippocampus of aged F344 rats. 1019 18


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