{beta}-Adrenoceptor function changes with age of subject in myocytes from non-failing human ventricle

doi:10.1016/S0008-6363(95)00187-5

Cardiovascular Research 1996 31(1):152-156; doi:10.1016/S0008-6363(95)00187-5
© 1996 by European Society of Cardiology

This Article

	FREE Full Text (PDF)
	E-letters: Submit a response
	Alert me when this article is cited
	Alert me when E-letters are posted
	Alert me if a correction is posted

Services

	Email this article to a friend
	Similar articles in this journal
	Similar articles in PubMed
	Alert me to new issues of the journal
	Add to My Personal Archive
	Download to citation manager
	Request Permissions
	Disclaimer

Google Scholar

	Articles by Davies, C.H.
	Articles by Harding, S.E.
	Search for Related Content

PubMed

	PubMed Citation
	Articles by Davies, C.H.
	Articles by Harding, S.E.

Social Bookmarking

	What's this?

β-Adrenoceptor function changes with age of subject in myocytes from non-failing human ventricle

C.H. Davies, N. Ferrara and S.E. Harding^*

Department of Cardiac Medicine, National Heart and Lung Institute, Dovehouse St., London SW3 6LY, UK

^* Corresponding author. Tel. (+44-171) 352 8121 ext. 3311; Fax (+44-171) 823 3392.

The contractile response to β-adrenoceptor stimulationhas been found to be reduced in single myocytes from failinghuman ventricle. A portion of that reduction was statisticallyrelated to the age of the patient. We have developed a methodfor obtaining viable contracting myocytes from small biopsiesof human ventricle, enabling experiments to be performed onnon-failing left ventricle from patients undergoing coronaryartery surgery. These subjects are generally in an older agerange than those we have previously obtained from donor hearts.The present study compares responses to isoproterenol and highCa²⁺ between myocytes from older (>50 years, n = 8) and younger(<40 years, n = 5) subjects. Myocytes from older patientsdid not differ in their contraction amplitude (10.7 ±1.0 cf. 10.8 ± 1.1% cell shortening), or contractionand relaxation velocities in high Ca²⁺ at a driving frequencyof 0.2 Hz (32 °C). The sensitivity to isoproterenol, asdetermined from the EC₅₀ value (concentration for half-maximaleffect), was also similar between age groups (1.16 ±0.64 nM young, cf. 2.76 ± 2.0 nM old), although higherthan in myocytes from failing hearts (22.3 ± 7.5 nM,n = 11). However, for the older group there was a significantdepression 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 contractionand relaxation velocities achieved in the presence of isoproterenolwere also depressed in older subjects (P < 0.02 for both).We conclude that age and/or coronary disease with unimpairedleft ventricular function selectively reduces the maximum effectof isoproterenol but not the concentration at which this occurs.

KEYWORDS Age; Adrenergic receptors; Human, ventricular myocytes, contractile function

Add to CiteULike CiteULike Add to Connotea Connotea Add to Del.icio.us Del.icio.us What's this?

This article has been cited by other articles:

B. Pelzmann, P. Schaffer, E. Bernhart, P. Lang, H. Machler, B. Rigler, and B. Koidl
L-type calcium current in human ventricular myocytes at a physiological temperature from children with tetralogy of Fallot
Cardiovasc Res, May 1, 1998; 38(2): 424 - 432.
[Abstract] [Full Text] [PDF]