Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By northern blot analysis and ribonuclease protection assay, we observed the presence of a high level of trkB mRNA in primary brain cultures devoid of neuronal cells and highly enriched in glial fibrillary acidic protein-positive astroglial cells prepared from newborn rat cerebral hemispheres, cerebral cortex, hippocampus, and striatum. In primary astroglial cultures, the more abundant trkB transcripts code for the truncated receptor without tyrosine kinase activity; probes specific for the full-length trkB mRNA did not detect any signal in northern blot analysis. By the sensitive ribonuclease protection assay, we could show the presence of trkC mRNA in cultured astrocytes, whereas no trkA mRNA was detected. We confirmed the presence of relatively high levels of nerve growth factor and neurotrophin-3 mRNA, and very low basal level of brain-derived neurotrophic factor mRNA. Moreover, we demonstrated that another member of the neurotrophin family, neurotrophin-4, is also expressed in cultured astroglial cells. In view of the fact that many functional receptors for conventional neurotransmitters or neuropeptides present on astroglial cells may act via the adenylate cyclase system, we studied also the effect of agents able to increase the intracellular cyclic AMP concentration. A sharp increase in the trkB mRNA level was observed after treatment of primary astroglial cultures with dibutyryl cyclic AMP, 8-bromo-cyclic AMP, or the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine. On the contrary, trkC mRNA levels were unaffected by treatment with cyclic AMP-elevating agents. All the neurotrophin mRNAs examined, except neutrophin-4, were increased by 3-isobutyl-1-methylxanthine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression of neurotrophins and their receptors in primary astroglial cultures: induction by cyclic AMP-elevating agents. 751 99

The presence of the neurotrophin, nerve growth factor, brain derived neurotrophic factor, neurotrophin-3 and neurotrophin-4 (NGF, BDNF, NT-3 and NT-4) and their receptors of the tyrosine kinase family (trkA, trkB and trkC) have been investigated in the choroid plexus and dura mater of the adult rat by ribonuclease protection assay. The choroid plexus contained high levels of mRNAs for NGF and NT-4, and low levels of NT-3 and BDNF mRNA; and high levels of trkB mRNA, and undetectable levels of trkA and trkC mRNA. In the dura mater there were high levels of NT-3 and NGF, and low levels of BDNF and NT-4 mRNAs; and high levels of trkC mRNA, and relatively high amount of trkB mRNA, while levels of trkA mRNA was undetectable. The present analysis revealed a different distribution of neurotrophins and their related receptors in the choroid plexus and dura mater.
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PMID:Expression of mRNAs for neurotrophins and their receptors in the rat choroid plexus and dura mater. 858 Apr 26

The expression of neurotrophin and neurotrophin receptor mRNAs in human granulocytes and bone marrow cells was examined using ribonuclease protection assay and reverse transcription-polymerase chain reaction. The granulocytes expressed mRNA coding for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-4 (NT-4), but not neurotrophin-3 (NT-3). Moreover, the inflammatory mediator leukotriene B4 (LTB4) up-regulated the expression of NT-4 mRNA in granulocytes, but did not affect the expression of other neurotrophin mRNAs. Granulocytes generally lacked expression of mRNA coding for neurotrophin receptors. In contrast, human bone marrow cells consistently expressed mRNA for trkB (the BDNF and NT-4 receptor) and displayed variable expression of mRNA coding for trkA (the tyrosine kinase NGF receptor) and LNGFR (the low-affinity NGF receptor), whereas mRNA for trkC (the NT-3 receptor) was not expressed. Contrary to granulocytes, normal bone marrow cells generally expressed only low levels of mRNA encoding BDNF and NT-4. Expression of mRNA encoding NGF and NT-3 was not detected. However, significantly increased expression of BDNF mRNA was observed when bone marrow cells from patients with chronic myeloproliferative disorders (MPD) were analyzed. The results suggest that neurotrophins may act as granulocyte-derived effector molecules and that human bone marrow cells may be targets for these compounds, in particular BDNF and NT-4.
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PMID:Expression of mRNA encoding neurotrophins and neurotrophin receptors in human granulocytes and bone marrow cells--enhanced neurotrophin-4 expression induced by LTB4. 971 63