Linked Life Data

8849600

Source:http://linkedlifedata.com/resource/pubmed/id/8849600

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-2-24
pubmed:abstractText
The contractile response to beta-adrenoceptor stimulation has been found to be reduced in single myocytes from failing human ventricle. A portion of that reduction was statistically related to the age of the patient. We have developed a method for obtaining viable contracting myocytes from small biopsies of human ventricle, enabling experiments to be performed on non-failing left ventricle from patients undergoing coronary artery surgery. These subjects are generally in an older age range than those we have previously obtained from donor hearts. The present study compares responses to isoproterenol and high Ca2+ between myocytes from older (> 50 years, n = 8) and younger (< 40 years, n = 5) subjects. Myocytes from older patients did not differ in their contraction amplitude (10.7 +/- 1.0 cf. 10.8 +/- 1.1% cell shortening), or contraction and relaxation velocities in high Ca2+ at a driving frequency of 0.2 Hz (32 degrees C). The sensitivity to isoproterenol, as determined from the EC50 value (concentration for half-maximal effect), was also similar between age groups (1.16 +/- 0.64 nM young, cf. 2.76 +/- 2.0 nM old), although higher than in myocytes from failing hearts (22.3 +/- 7.5 nM, n = 11). However, for the older group there was a significant depression in maximum contraction amplitude with isoproterenol (8.5 +/- 0.6 cf. 11.5 +/- 1.0% cell shortening, P < 0.05) and in the ratio between this and the maximum Ca2+ response (isoproterenol/Ca2+ ratio, 0.79 +/- 0.05 cf. 1.16 +/- 0.12, P < 0.05). Concomitantly, the maximum contraction and relaxation velocities achieved in the presence of isoproterenol were also depressed in older subjects (P < 0.02 for both). We conclude that age and/or coronary disease with unimpaired left ventricular function selectively reduces the maximum effect of isoproterenol but not the concentration at which this occurs.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0008-6363
pubmed:author
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
152-6
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Beta-adrenoceptor function changes with age of subject in myocytes from non-failing human ventricle.
pubmed:affiliation
Department of Cardiac Medicine, National Heart and Lung Institute, London, UK.
pubmed:publicationType
Journal Article