Linked Life Data

20978120

Source:http://linkedlifedata.com/resource/pubmed/id/20978120

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2011-1-19
pubmed:abstractText
Although G protein-coupled receptors are often categorized in terms of their primary coupling to a given type of G? protein subunit, it is now well established that many show promiscuous coupling and activate multiple signaling pathways. Furthermore, some agonists selectively activate signaling pathways by promoting interaction between distinct receptor conformational states and particular G? subunits or alternative signaling proteins. We have tested the capacity of agonists to stimulate Ca(2+) release, cAMP accumulation, and changes in extracellular acidification rate (ECAR) at the human ?(1A)-adrenoceptor. Signaling bias factors were determined by novel application of an operational model of agonism and compared with the reference endogenous agonist norepinephrine; values significantly different from 1.0 indicated an agonist that promoted receptor conformations distinct from that favored by norepinephrine. Oxymetazoline was a full agonist for ECAR and a partial agonist for Ca(2+) release (bias factor 8.2) but failed to stimulate cAMP production. Phenylephrine showed substantial bias toward ECAR versus Ca(2+) release or cAMP accumulation (bias factors 21 and 33, respectively) but did not display bias between Ca(2+) and cAMP pathways. Cirazoline and N-[5-(4,5-dihydro-1H-imidazol-2-yl)-2-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl]methanesulfonamide (A61603) displayed bias toward cAMP relative to Ca(2+) release (bias factors of 7.4 and 8.6). It is noteworthy that epinephrine, a second endogenous adrenoceptor agonist, did not display bias relative to norepinephrine. Our finding that phenylephrine displayed significant signaling bias, despite being highly similar in structure to epinephrine, indicates that subtle differences in agonist-receptor interaction can affect conformational changes in cytoplasmic domains and thereby modulate the repertoire of effector proteins that are activated.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1521-0111
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
298-307
pubmed:dateRevised
2011-3-28
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Quantification of functional selectivity at the human ?(1A)-adrenoceptor.
pubmed:affiliation
Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, 399 Royal Parade, Parkville, Victoria 3052, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't