Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

mu-Opioid receptor agonist [D-Ala2,NMe-Phe4,Gly5-ol]enkephalin (DAMGO)-induced peripheral analgesic effects occur early in hindpaws inoculated with Freund's complete adjuvant and increase in parallel to the development of inflammatory signs. Antagonism of these effects by beta-funaltrexamine, an irreversible mu-opioid receptor antagonist, suggests that the effective number of peripheral opioid receptors does not increase during early stages, but does so at later stages of the inflammation. As determined by a ribonuclease protection assay, mu-opioid receptor mRNA in dorsal root ganglia is abundant in untreated animals, but does not significantly increase following inflammation. Thus, peripheral analgesic efficacy of DAMGO is not correlated with transcription or number of mu-opioid receptors at early inflammatory stages. At later stages, however, the number of peripheral mu-opioid receptors appears to increase and may enhance opioid efficacy.
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PMID:Inflammation enhances peripheral mu-opioid receptor-mediated analgesia, but not mu-opioid receptor transcription in dorsal root ganglia. 755 97

The existence of opioid receptors within glial cell membranes has been proposed by several laboratories based on biochemical and radioligand binding data. The recent cloning of the mu, delta and kappa receptors has enabled us to directly examine the issue of opioid receptor expression in rat brain astroglia by using solution hybridization/ribonuclease protection assays to analyze the total RNA obtained from primary cultures of cortical, striatal, cerebellar, hippocampal and hypothalamic astrocytes. The results indicate that all five glial cultures expressed mu, delta and kappa receptor mRNA. The rank order of receptor mRNA abundance, expressed collectively across all five cultures, was determined to be delta > or = kappa >> mu. An analysis of the glial distribution profile for each receptor type revealed that mu receptor mRNA levels were the most abundantly expressed in cortical cultures, while the greatest levels of delta receptor mRNA were found in the cortical and hypothalamic cultures, and significant kappa receptor mRNA levels were produced by the cortical, hypothalamic and cerebellar cultures. Furthermore, the five glial cultures each expressed different levels of total opioid receptor (mu + delta + kappa) mRNA. The rank order of total opioid receptor mRNA expression across different astroglial cultures was found to be cortex > hypothalamus > cerebellum = hippocampus > striatum. An analysis of the relative expression profiles for mu, delta and kappa receptor mRNA within each culture revealed that all cultures manifested relatively high levels of delta and kappa receptor mRNA, but relatively low levels of mu receptor mRNA. Generally, cortical, hippocampal and hypothalamic cultures were characterized by comparable levels of delta and kappa receptor mRNA, and little, if any, mu receptor mRNA. However, striatal cultures were characterized by a high level of delta receptor mRNA which was approximately twice and four times that of the kappa and mu receptor mRNA, respectively. In contrast, cerebellar cultures expressed predominantly kappa receptor mRNA at a level which was almost twice that of the delta receptor mRNA, and expressed very little mu receptor mRNA. These data show that primary astroglial cultures not only express mu, delta and kappa receptor mRNAs, but they do so in a manner dependent upon receptor type and brain region. This suggests a regional heterogeneity of astrocytes with respect to opioid receptor expression, a characteristic previously described only for neurons. Furthermore, it suggests the existence of an additional anatomical component in CNS opioid systems.
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PMID:Primary astroglial cultures derived from several rat brain regions differentially express mu, delta and kappa opioid receptor mRNA. 875 Aug 24

Previous radioligand-binding studies have reported conflicting results concerning the effect of chronic morphine administration on the regulation of mu-opioid receptor (MOR) density. On the other hand, chronic administration of an opioid antagonist, such as naltrexone, has been shown to increase the density of the MOR. In order to determine if the changes in the MOR are associated with alterations in receptor mRNA levels, we investigated MOR gene expression following chronic treatment with morphine and/or naltrexone. MOR mRNA levels, determined by the ribonuclease protection assay (RPA), were unchanged with respect to control during chronic morphine treatment and morphine withdrawal in each of the analysed brain areas. Furthermore, chronic administration of naltrexone did not result in changes of MOR mRNA levels in rat striatum of naive and morphine-dependent rats, suggesting that the up-regulation of the MOR density, at least in this tissue, is not regulated at transcriptional level.
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PMID:Chronic morphine and naltrexone fail to modify mu-opioid receptor mRNA levels in the rat brain. 910 83

Dual promoters were identified in the mouse kappa-opioid receptor (KOR) gene. The distal promoter was located in the 5'-upstream region of exon 1 and the proximal promoter was located in the first intron of this gene. The transcription initiation site of the proximal promoter was mapped to the -93rd nucleotide position from the ATG codon in a primer extension experiment. The expression of KOR mRNAs transcribed from these two promoters in mouse central nervous system and an embryonal carcinoma cell line P19 was confirmed in a ribonuclease protection assay. In non-neuronal tissues, only the transcripts initiated from the distal promoter were detected. The biological activities of these two promoters were determined in transient transfection of P19 cells with a series of reporters, each truncated at various 5'-upstream regions. It was concluded that the distal promoter was located between nucleotide positions -990 and -570, and the proximal promoter was located between nucleotide positions -330 and -93, relative to the translation initiation codon. The presence of dual promoters in the KOR gene suggested potential regulation of KOR expression by using different promoters.
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PMID:Studies of dual promoters of mouse kappa-opioid receptor gene. 928 3

In sequel to our preliminary observations with peptidomimetic opioid compounds, we have further investigated immunomodulatory activity of one peptidomimetic compound (Tyr-NH-CH2-CH2-O-Phe-NH2) with peripheral blood mononuclear cells (PBMCs) of healthy volunteers/tuberculosis patients. This peptidomimetic compound was evaluated for its effect on purified protein derivative (PPD) stimulated lymphocyte proliferation in vitro, production of Th1 and Th2 cytokines by ELISA and ribonuclease protection assay. Our study shows the immunosuppressive potential of above synthetic peptidomimetic compound. This compound inhibited PPD stimulated human lymphocyte proliferation and this inhibition was reversed by opioid receptor antagonist, naloxone. Its immunosuppressive effect was further demonstrated by inhibition of interleukin-9 (IL-9), IL-10 but failed to influence IL-2, IL-15 and interferon-y (IFN-gamma) in PPD stimulated human PBMCs.
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PMID:Inhibition of antigen specific lymphocyte proliferation and cytokine stimulation by peptidomimetic opioid compound. 1209 65

The reverse transcriptase-polymerase chain reaction (RT-PCR) was used to clone a cDNA fragment of a putative G-protein-coupled receptor from rat brain total RNA. Nucleotide sequencing of this cDNA fragment showed it to be homologous to that of the mu-opioid receptor splice variant MOR(1C) from mice. We used the cDNA to make an RNA probe for a ribonuclease protection assay (RPA). The results from the RPA showed a protected fragment of the size expected for MOR(1C) mRNA, as well as other RNase-protected fragments that may indicate the existence of other MOR1 transcripts. We then used the RNA probe for in situ hybridization (ISH) experiments. We detected strong autoradiographic labeling over much of the rat telencephalon, diencephalon, mesencephalon, cerebellum, spinal cord, and dorsal root ganglia. These findings suggest that MOR(1C), and possibly other MOR1 splice variants, are important components of the system by which the actions of opioids are transduced.
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PMID:Expression of MOR1C-like mu-opioid receptor mRNA in rats. 1510 Oct 90