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Article: Long-term carbachol treatment-induced down-regulation of muscarinic M2-receptors but not m2 receptor mRNA in a human lung cell line

TitleLong-term carbachol treatment-induced down-regulation of muscarinic M2-receptors but not m2 receptor mRNA in a human lung cell line
Authors
Issue Date1995
PublisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www.wiley.com/bw/journal.asp?ref=0007-1188&site=1
Citation
British Journal Of Pharmacology, 1995, v. 116 n. 3, p. 2027-2032 How to Cite?
Abstract1. The molecular mechanisms involved in the regulation of muscarinic receptor gene expression are poorly understood. We have investigated the effect of homologous stimulation on the regulation of M2 muscarinic receptor protein and gene in human embryonic lung fibroblasts (HEL 299 cells). 2. Saturation studies performed with the non-selective hydrophilic ([3H]-N-methyl-scopolamine, [3H]-NMS) and lipophilic ([3H]-quinuclidinyl benzilate, [3H]-QNB) muscarinic antagonists revealed a single class of high affinity binding sites. 3. Carbachol (1 mM) induced a rapid down-regulation of [3H]-NMS binding sites. Within 12 h, the process had approached steady state with 40 to 60% loss of receptors at 12 and 24 h. 4. The loss of [3H]-QNB binding sites (40% reduction at 24 h) occurred at a slower rate than did loss of [3H]-NMS binding sites as a result of receptor sequestration. 5. Carbachol treatment was accompanied by a functional desensitization of the receptor after 24 h of agonist treatment. In untreated cells, forskolin induced a large increase in cyclic AMP accumulation which was inhibited significantly by carbachol. The inhibitory effect of carbachol on forskolin-induced cyclic AMP accumulation was lost following 24 h carbachol stimulation. 6. The steady state level of muscarinic m2 mRNA measured by Northern blot analysis was not affected by carbachol treatment over the time course investigated and half-life studies with actinomycin D suggest that carbachol had no effect on the stability of m2 mRNA. 7. The rate of transcription of m2 muscarinic receptor gene as measured by nuclear RNA run-on assay was unaltered by carbachol stimulation. 8. These results suggest that homologous sequestration, desensitization, and down-regulation of M2 muscarinic receptors in HEL 299 cells does not involve transcriptional or post-transcriptional modifications of m2 muscarinic receptor mRNAs.
Persistent Identifierhttp://hdl.handle.net/10722/162107
ISSN
2015 Impact Factor: 5.259
2015 SCImago Journal Rankings: 2.368
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorHaddad, EBen_US
dc.contributor.authorRousell, Jen_US
dc.contributor.authorMak, JCWen_US
dc.contributor.authorBarnes, PJen_US
dc.date.accessioned2012-09-05T05:17:23Z-
dc.date.available2012-09-05T05:17:23Z-
dc.date.issued1995en_US
dc.identifier.citationBritish Journal Of Pharmacology, 1995, v. 116 n. 3, p. 2027-2032en_US
dc.identifier.issn0007-1188en_US
dc.identifier.urihttp://hdl.handle.net/10722/162107-
dc.description.abstract1. The molecular mechanisms involved in the regulation of muscarinic receptor gene expression are poorly understood. We have investigated the effect of homologous stimulation on the regulation of M2 muscarinic receptor protein and gene in human embryonic lung fibroblasts (HEL 299 cells). 2. Saturation studies performed with the non-selective hydrophilic ([3H]-N-methyl-scopolamine, [3H]-NMS) and lipophilic ([3H]-quinuclidinyl benzilate, [3H]-QNB) muscarinic antagonists revealed a single class of high affinity binding sites. 3. Carbachol (1 mM) induced a rapid down-regulation of [3H]-NMS binding sites. Within 12 h, the process had approached steady state with 40 to 60% loss of receptors at 12 and 24 h. 4. The loss of [3H]-QNB binding sites (40% reduction at 24 h) occurred at a slower rate than did loss of [3H]-NMS binding sites as a result of receptor sequestration. 5. Carbachol treatment was accompanied by a functional desensitization of the receptor after 24 h of agonist treatment. In untreated cells, forskolin induced a large increase in cyclic AMP accumulation which was inhibited significantly by carbachol. The inhibitory effect of carbachol on forskolin-induced cyclic AMP accumulation was lost following 24 h carbachol stimulation. 6. The steady state level of muscarinic m2 mRNA measured by Northern blot analysis was not affected by carbachol treatment over the time course investigated and half-life studies with actinomycin D suggest that carbachol had no effect on the stability of m2 mRNA. 7. The rate of transcription of m2 muscarinic receptor gene as measured by nuclear RNA run-on assay was unaltered by carbachol stimulation. 8. These results suggest that homologous sequestration, desensitization, and down-regulation of M2 muscarinic receptors in HEL 299 cells does not involve transcriptional or post-transcriptional modifications of m2 muscarinic receptor mRNAs.en_US
dc.languageengen_US
dc.publisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www.wiley.com/bw/journal.asp?ref=0007-1188&site=1en_US
dc.relation.ispartofBritish Journal of Pharmacologyen_US
dc.subject.meshBinding, Competitiveen_US
dc.subject.meshBlotting, Northernen_US
dc.subject.meshCarbachol - Pharmacologyen_US
dc.subject.meshCell Lineen_US
dc.subject.meshCyclic Amp - Metabolismen_US
dc.subject.meshDactinomycin - Pharmacologyen_US
dc.subject.meshDown-Regulation - Drug Effectsen_US
dc.subject.meshFibroblasts - Cytology - Drug Effectsen_US
dc.subject.meshGene Expression Regulation - Drug Effects - Geneticsen_US
dc.subject.meshHumansen_US
dc.subject.meshLung - Cytology - Drug Effects - Embryologyen_US
dc.subject.meshMuscarinic Agonists - Metabolismen_US
dc.subject.meshN-Methylscopolamineen_US
dc.subject.meshRna, Messenger - Genetics - Metabolismen_US
dc.subject.meshReceptor, Muscarinic M2en_US
dc.subject.meshReceptors, Muscarinic - Drug Effects - Genetics - Metabolismen_US
dc.subject.meshScopolamine Derivatives - Metabolismen_US
dc.subject.meshTranscription, Genetic - Drug Effects - Geneticsen_US
dc.titleLong-term carbachol treatment-induced down-regulation of muscarinic M2-receptors but not m2 receptor mRNA in a human lung cell lineen_US
dc.typeArticleen_US
dc.identifier.emailMak, JCW:judymak@hku.hken_US
dc.identifier.authorityMak, JCW=rp00352en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1111/j.1476-5381.1995.tb16407.x-
dc.identifier.pmid8640341-
dc.identifier.scopuseid_2-s2.0-0029150945en_US
dc.identifier.volume116en_US
dc.identifier.issue3en_US
dc.identifier.spage2027en_US
dc.identifier.epage2032en_US
dc.identifier.isiWOS:A1995RX83600012-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridHaddad, EB=7102803008en_US
dc.identifier.scopusauthoridRousell, J=6602560061en_US
dc.identifier.scopusauthoridMak, JCW=7103323094en_US
dc.identifier.scopusauthoridBarnes, PJ=36064679400en_US

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