Linked Life Data

8074232

Source:http://linkedlifedata.com/resource/pubmed/id/8074232

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2 Pt 1
pubmed:dateCreated
1994-9-23
pubmed:abstractText
Voltage-dependent and receptor-operated Ca2+ entry mechanisms have been demonstrated in airway smooth muscle, but their relative importance for maintenance of contraction is unknown. Blockade of voltage-dependent Ca2+ channels (VDC) has produced inconsistent relaxation. We postulated regional variations in Ca2+ handling by airway smooth muscle cells and compared the efficacy of dihydropyridine VDC blockers in tracheas and bronchi. Porcine tracheal smooth muscle strips and bronchial rings were mounted in tissue baths filled with physiological solutions and isometric tension was measured. Tissues were precontracted with carbachol or KCl, and relaxation dose-response curves to nifedipine, Mn2+, or Cd2+ were obtained. Relaxation responses to nifedipine were significantly different in carbachol-contracted tracheas and bronchi. Whereas carbachol-contracted tracheal muscle completely relaxed with 10(-6) M nifedipine, bronchial smooth muscle relaxed < 50%. In contrast, KCl-contracted bronchial muscle was completely relaxed by nifedipine. The nonspecific Ca2+ channel blockers Mn2+ and Cd2+ produced similar relaxation responses in each tissue. Thus VDC are the predominant mechanism for Ca2+ entry in porcine tracheal smooth muscle, but a dihydropyridine-insensitive pathway is functionally important in carbachol-contracted porcine bronchi. Regional variation may account for apparent inconsistencies between previous studies.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
L106-12
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Expression of dihydropyridine resistance differs in porcine bronchial and tracheal smooth muscle.
pubmed:affiliation
Department of Environmental Health Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.