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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-8-10
pubmed:abstractText
We have used the [3H]resiniferatoxin (RTX) binding assay to characterize for the first time a vanilloid (capsaicin) receptor in tracheobronchial tissues of the guinea pig. Membranes obtained from the trachea and the main bronchi bound RTX with an affinity of 1 nM; the cooperativity index was close to unity, indicating noncooperative binding. Specific [3H]RTX binding was fully inhibited by capsaicin (Ki = 500 nM) and capsazepine (Ki = 100 nM), but it was not inhibited at all by the inactive RTX structural analog resiniferonol 9, 13, 14-orthophenylacetate (10 microM), confirming the specificity of the binding. Neither was RTX binding inhibited by the functional vanilloid antagonist ruthenium red (100 microM). The density of specific RTX binding sites was similar in the trachea (Bmax = 150 fmol/mg protein) and the bronchi (Bmax = 170 fmol/mg protein). In keeping with the marked resistance of hamsters to capsaicin actions, no specific RTX binding could be detected in the airways of this species. By contrast, we have been able to demonstrate specific RTX binding sites in human bronchi: the estimated affinity for RTX, 2 nM, was similar to that (7 nM) determined in guinea pig bronchi. We conclude that (1) the [3H]RTX binding assay affords a novel biochemical marker for vanilloid-sensitive nerves in the airways, and (2) this binding assay may be a useful tool to explore species-related differences in the expression and pharmacologic profile of vanilloid receptors in the airways.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1073-449X
pubmed:author
pubmed:issnType
Print
pubmed:volume
152
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
59-63
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Resiniferatoxin binding to vanilloid receptors in guinea pig and human airways.
pubmed:affiliation
Department of Physiology and Pharmacology, Karolinska Institute, Sweden.
pubmed:publicationType
Journal Article