Cardiac beta-adrenergic receptor function in fetal sheep exposed to long-term high-altitude hypoxemia

The American Journal of Physiology
V A BrowneR D Gilbert

Abstract

In this study, we hypothesized that a reduction in beta-adrenergic receptor number or a decrease in functional coupling of the receptor to the adenylate cyclase system may be responsible for the blunted inotropic response to isoproterenol observed in fetal sheep exposed to high altitude (3,820 m) from 30 to 138-142 days gestation. We measured the contractile response to increasing doses of isoproterenol and forskolin in papillary muscles from both ventricles, estimated beta-adrenergic receptor density (Bmax) and ligand affinity (Kd) using [125I]iodocyanopindolol, and measured adenosine 3',5'-cyclic monophosphate (cAMP) levels before and after maximally stimulating doses of isoproterenol and forskolin. Left ventricular wet weight was unchanged, but right ventricular weight was 20% lower than controls. At the highest concentration of isoproterenol (10 microM), maximum active tension was 32 and 20% lower than controls in hypoxemic left and right ventricles, respectively. The contractile response to forskolin was severely attenuated in both hypoxemic ventricles. Bmax was unchanged in the left ventricle, but increased by 55% in the hypoxemic right ventricle. Kd was not different from controls in either ventricle. Basal cAMP levels w...Continue Reading

References

Feb 1, 1975·The American Journal of Physiology·J T MaherL H Hartley
Jul 1, 1992·Journal of Molecular and Cellular Cardiology·K A Webster, N H Bishopric
Oct 1, 1992·Journal of Applied Physiology·R KacimiB Crozatier
Apr 1, 1991·Circulation Research·C W PinsonK L Thornburg
Nov 1, 1989·Trends in Pharmacological Sciences·A LaurenzaK B Seamon
Nov 1, 1988·Journal of Applied Physiology·J P RichaletF Lhoste
Jan 1, 1986·Developmental Pharmacology and Therapeutics·J F PadburyD A Fisher
Mar 1, 1974·Journal of Applied Physiology·L H HartleyJ C Cruz
Jan 1, 1968·Annual Review of Medicine·H N Hultgren, R F Grover
Dec 1, 1967·Journal of Applied Physiology·J K AlexanderR F Grover
Jul 22, 1982·The New England Journal of Medicine·M R BristowE B Stinson
Jul 1, 1984·The Journal of Clinical Investigation·M R BristowW Minobe
Sep 1, 1993·American Journal of Obstetrics and Gynecology·M KamitomoR D Gilbert

❮ Previous
Next ❯

Citations

May 22, 2009·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Isa Lindgren, Jordi Altimiras
Oct 13, 2000·American Journal of Physiology. Cell Physiology·J M PeiT M Wong
May 31, 2008·Journal of Applied Physiology·Wen YinJian-Ming Pei
May 17, 2003·American Journal of Physiology. Heart and Circulatory Physiology·Soochan BaeLubo Zhang
Oct 24, 2007·American Journal of Physiology. Lung Cellular and Molecular Physiology·Christine E BixbyJ Usha Raj
Aug 24, 2018·Journal of Applied Physiology·Dana S HutchinsonFlora Y Wong
Jul 27, 2007·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Bert WibbensAlistair J Gunn

❮ Previous
Next ❯

Related Concepts

Related Feeds

Adrenergic Receptors: Trafficking

Adrenergic receptor trafficking is an active physiological process where adrenergic receptors are relocated from one region of the cell to another or from one type of cell to another. Discover the latest research on adrenergic receptor trafficking here.

Cardiomegaly

Cardiomegaly, known as an enlarged heart, is a multifactorial disease with different pathophysiological mechanisms. Hypertension, pregnancy, exercise-induced and idiopathic causes are some mechanisms of cardiomegaly. Discover the latest research of cardiomegaly here.