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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. These experiments investigated the action of histamine on local inhibition in the CA1 region of the in vitro hippocampal slice preparation using a paired-pulse paradigm. 2. We observed that histamine produced a concentration-dependent and reversible attenuation of paired-pulse inhibition. This effect was reduced by the H2 receptor antagonist, cimetidine, and mimicked by the H2 receptor agonist, impromidine. 3. We also observed that histamine produced concentration-dependent effects on the amplitude of the population spike that could be correlated with alterations in the field excitatory postsynaptic potential (EPSP) amplitude and input fiber volley. High concentrations of histamine produced a reduction in the amplitude of the population spike which was always accompanied by a reduction in the EPSP and fiber volley amplitude. 4. These results suggest that histamine, through the occupancy of H2 receptors, acts to modulate the efficacy of the local synaptic circuitry which is involved in producing paired-pulse inhibition in the hippocampus.
Cell Mol Neurobiol 1988 Dec
PMID:Histamine modulates local inhibition in the rat hippocampal slice. 297 67

Concentrates of the epimastigote stage of Trypanosoma cruzi stocks derived from single cell clones and cultured under identical conditions display a spectrum of 'colors' varying from dark brown to milk white. The color of the concentrate is reproducible for a parasite stock. An essential component of the culture medium for epimastigote growth is hemin, an iron-containing compound. Consequently, it seemed possible that the color spectrum of the epimastigote stocks reflected differences in the uptake, concentration or utilization of iron. This report describes the quantitative studies utilizing electron probe X-ray elemental mapping, energy dispersive X-ray microanalysis, and energy dispersive X-ray fluorescence spectrometry of the epimastigote stage of two T. cruzi stocks (CA-I/72 and HO-3/15) which display extreme color differences. Striking and statistically significant quantitative differences were found in the levels of Fe, Zn, and K between the two stocks. On the basis of atomic ratios, the CA-I/72 stock contains approximately two-fold more Fe per cell than the HO-3/15 stock. However, in the case of Zn the ratio is reversed; the HO-3/15 stock contains approximately two-fold more Zn per cell than the CA-I/72 stock. The marked inter-stock differences which exist in the levels of several elements could modulate the pathogenicity, survival, or adaptability of T. cruzi and, consequently, be important factors in our understanding of the complex problem of Chagas' disease.
Mol Biochem Parasitol 1988 Oct
PMID:Trypanosoma cruzi: elemental composition heterogeneity of cloned stocks. 305 39

Biochemical, immunocytochemical and histochemical methods were used to study the effect of chronic acetazolamide treatment on carbonic anhydrase (CA) isoenzymes in the rat kidney. Male inbred rats (Lew/Mol) were treated with 15 mg kg-1 day-1 acetazolamide s.c. by Alzet minipump during 2-9 weeks; some animals had a drug-free period of 1-4 weeks before being killed. The renal content of CA II was higher in the acetazolamide-treated rats than in the controls, 178 +/- 10 vs 144 +/- 4.8 micrograms enzyme protein g-1 tissue (mean +/- SE). The distribution of CA isoenzymes did not change during or after chronic acetazolamide treatment. Thus, only CA II was detected in the kidney tubules by immunofluorescence using specific antisera against CA I, CA II and CA III. All animals showed a similar staining pattern, with intense cytoplasmic CA II staining in intercalated cells of collecting ducts, moderate staining in descending thin limbs of Henle, and weak cytoplasmic staining in proximal tubules and chief cells of collecting ducts. All animals also showed histochemical staining of cell membranes in proximal and distal tubules and thick limbs of Henle, suggesting the presence of a membrane-bound isoenzyme (CA IV). The only difference noted by histochemistry and immunocytochemistry was that the intercalated cells appeared bulkier and protruded more markedly into the tubular lumen in treated than in untreated animals. The functional importance of this finding is unclear. The observed changes in CA cannot alone explain why the effect of acetazolamide, in causing loss of bicarbonate and sodium, is self-limited on continued administration.
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PMID:Carbonic anhydrase isoenzymes in the rat kidney. Effects of chronic acetazolamide treatment. 308 5

The human carbonic anhydrase isozymes represent a family of homologous proteins which are important in respiratory function, fluid secretion, and maintenance of cellular acid-base homeostasis. Using somatic cell genetic techniques we have mapped two of the CA genes (CA1 and CA3) to human chromosome 8. In situ hybridization data demonstrates that both CA1 and CA3 map to the same region (q13-q22) of chromosome 8.
Somat Cell Mol Genet 1987 Mar
PMID:Regional localization of carbonic anhydrase genes CA1 and CA3 on human chromosome 8. 310 94

An in situ hybridization procedure was applied to quantify glucocorticoid receptor (GR) mRNAs in the hippocampus of rat brain. Hybridization was carried out using a radiolabeled antisense probe complementary to the rat liver GR gene. The specificity of the method was validated by showing: 1) a high cellular grain density in sections hybridized with an antisense but not a sense probe; 2) agreement between the experimental and theoretical temperature at which 50% of the hybrids melted, and 3) a high signal distribution of GR mRNA in the hippocampus, a region of brain known to preferentially concentrate steroid hormones. Within the hippocampus, however, subregional differences in hybridization densities were observed. Quantitative autoradiography indicated that the average neuronal silver grain number was highest in the pyramidal cell layers of CA2 and CA4 and lowest in those of CA1 and CA3. Also, there was a significant difference in the average grain number between all of the cell fields except for that between CA2 and CA4. These results show that contiguous but neuroanatomically distinct cell fields of the hippocampus express different levels of GR transcripts, and indicate that differential regulation of GR expression occurs in subpopulations of hippocampal neurons.
Mol Endocrinol 1988 Aug
PMID:Localization of glucocorticoid receptor messenger ribonucleic acid in hippocampus of rat brain using in situ hybridization. 321 Nov 54

Extracellular recording techniques were used to study the effects of dopamine on postactivation excitability of rat area CA1 hippocampal neurons maintained in vitro. Population spikes were elicited by delivery of conditioning and test stimulus pulses to afferent fibers. The interval between the conditioning and test volley was set to separate delivery of stimuli by 10 to 80 msec. The effect of superfusion or microtopical application of dopamine (DA) on population responses to test stimulus pulses was studied. When paired stimulus volleys, separated by brief intervals (up to 40 msec), were delivered to afferent fibers, paired-pulse suppression (PPS) was indicated by the amplitude of the population spike elicited by the test volley being smaller than that elicited by the conditioning volley. When paired volleys were separated by longer intervals (40 to 80 msec), the response elicited by the test volley was larger in amplitude than that elicited by the conditioning volley, indicating paired-pulse facilitation (PPF). Following exposure to DA, the amplitude of the population response elicited by the conditioning volley was larger than the amplitude before exposure to DA. This effect was long-lasting, enduring for tens of minutes. However, when the amplitude of the conditioning population response was held constant, the PPS was decreased, indicating disinhibition. It is suggested that dopamine produces a long-lasting attenuation of an intervening inhibitory influence onto CA1 pyramidal neurons.
Cell Mol Neurobiol 1984 Jun
PMID:Modulation by dopamine of population spikes in area CA1 hippocampal neurons elicited by paired stimulus pulses. 609 84

The 250 MHz 1H-NMR spectrum of horse carbonic anhydrase I (or B) (carbonate hydro-lyase, EC 4.2.1.1) was measured as a function of pH under various conditions. Eight resonances corresponding to histidine C-2 protons and four resonances corresponding to histidine C-4 protons were identified and assigned to individual histidine residues in the enzyme molecule. Substantial similarities between horse and human carbonic anhydrases I were demonstrated. While the human enzyme has three titratable histidine residues in its active site, the horse enzyme has only two, His-67 in the human enzyme being replaced by Gln in the horse enzyme (Jabusch, J.R., Bray, R.P. and Deutsch, H.F. (1980) J. Biol. Chem. 255, 9196-9204). This substitution has small but significant effects on the behaviour of the other active-site histidines. His-64 and His-200. However, His-64 has an anomalously low pKa value also in horse isoenzyme I, as previously observed in human isoenzyme I (Campbell, I.D., Lindskog, S. and White, A.I. (1974) J. Mol. Biol. 90, 469-489).
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PMID:Proton nuclear magnetic resonance studies of histidines in horse carbonic anhydrase I. 641 19

The properties of two virulent streptococcal bacteriophages and their DNAs have been studied. Both phage A25 and phage CA1 generated the generalized transduction of chromosomal and plasmid markers among group A streptococci. Phage CA1 differs from the morphologically and serologically related and well-known transducing phage A25 by the efficiency of transduction, the duration of the latent period of reproduction, buoyant density in CsCl and by the lytic spectrum. Phage CA1 also was active against the lysogens resistant to phage A25. Phage genomes are presented as the linear permutated DNA molecules with molecular mass of 23 megadaltons having terminal repetitions of different size. These data have been obtained as a result of homoduplex analysis of the DNAs. A non-homologous fragment 29% of the molecular length of the phage genomes has been revealed by heteroduplex analysis of phage DNAs. This fragment seems to be responsible for the differences in biological properties of the phages. Phage A25 is heterogenous in buoyant density and molecular length of its DNA.
Mol Biol (Mosk)
PMID:[Comparative characters of the transducing virulent streptococcal phages A25 and CA1]. 702 85

Injection of small volumes of N-methyl-D-aspartate (NMDA) or Sin-1 molsidomine (a nitric oxide releasing agent) onto the dendrites of granule cells in the hippocampal dentate gyrus leads to changes in the level of expression of a number of genes. There is a fall in prodynorphin mRNA levels with a corresponding increase in proenkephalin mRNA levels. Similar changes in opioid gene expression occur following the induction of long-term potentiation (LTP). We report here that at short time periods (1-6 h) after injections of NMDA or sin-1 molsidomine, there is an increase in the levels of the mRNA encoding the alpha subunit of Ca2+/calmodulin-dependent protein kinase II (CaMKII alpha), consistent with a report of elevated CaMKII alpha mRNA in postsynaptic neurons in the CA1 region of the hippocampus following LTP induction [54]. However, we also report that 24 h after injection of NMDA or sin-1, there is a dramatic decrease in CaMKII alpha mRNA levels in the vicinity of the injection. This effect is specific for CaMKII alpha mRNA, in that many other mRNA species are not affected, and occurs in the dendritic population of CaMKII alpha mRNA as well as in the pool of mRNA in the granule cell bodies. The effect is blocked by an inhibitor of cGMP-dependent protein kinase. The biphasic regulation of CaMKII alpha mRNA may be of considerable functional importance for the long-term response of granule cells to local stimulation of NMDA receptors or NO release.
Brain Res Mol Brain Res 1995 Jul
PMID:N-methyl-D-aspartate and nitric oxide regulate the expression of calcium/calmodulin-dependent kinase II in the hippocampal dentate gyrus. 747 22

The distribution of AMPA-selective subunits, GluR1-4, was determined in the human hippocampus and cerebellum by in situ hybridization and immunocytochemistry. In the hippocampus, in situ hybridization revealed that GluR1 and GluR2 mRNAs were similarly distributed and highly expressed in the dentate gyrus, with lower levels in the CA regions. GluR3 and GluR4 mRNAs were expressed at very low levels. Immunocytochemical studies showed that GluR1- and GluR2/3-immunoreactivity were highest in the dentate molecular and granular layers. In the CA regions, GluR1 and GluR2/3 staining was observed in pyramidal cell bodies and surrounding neuropil and was more intense in CA4/3/2 compared with CA1. GluR4-immunoreactivity was low throughout the hippocampus. In the cerebellum, GluR1 and GluR4 transcripts were expressed in the granular and Purkinje cell/Bergmann glia layers. GluR2 mRNA was highly expressed in the granular layer and individual Purkinje cells, while GluR3 mRNA was not detectable in the cerebellum. GluR1- and GluR4-immunoreactivity were localized to Purkinje cells and putative Bergmann glia, as well as their processes extending into the molecular layer. GluR2/3 staining was intense in Purkinje cells, with moderate staining in the granular layer. Thus, GluR1-4 subunits are differentially distributed in the hippocampus and cerebellum. In addition, the distribution of subunit mRNA and protein correlate well with each other and with the glutamatergic neuroanatomy of the hippocampus and cerebellum.
Brain Res Mol Brain Res 1995 Jul
PMID:Distribution of AMPA-selective glutamate receptor subunits in the human hippocampus and cerebellum. 747 26


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