PMID: 8945889Nov 1, 1996Paper

Regulation of alpha 1-, beta 1-, and beta 2-adrenergic receptors in rat heart by norepinephrine

The American Journal of Physiology
M ZhaoK H Muntz

Abstract

Previous studies suggest that the desensitization and downregulation of beta 1-adrenergic receptors (beta 1-AR) in the failing heart are the result of the elevated plasma catecholamine levels associated with this disease. To examine norepinephrine (NE)-induced regulation of cardiac adrenergic receptors, rats were infused with l-NE (200 micrograms.kg-1.h-1 for 7 days) or vehicle (0.001 N HCl) by implantation of osmotic minipumps. The technique of coverslip autoradiography was used to quantify alpha 1-adrenergic receptors (alpha 1-AR), beta 1-AR, and beta 2-AR in different tissue compartments of rat hearts. For measurement of beta-AR binding, sections were incubated with 70 pM [125I]iodocyanopindolol (ICYP) alone or in the presence of 5 microM dl-propranolol or 5 x 10(-7) M CGP-20712A (a beta 1-antagonist) and then set up for autoradiography. [3H]prazosin (1 nM) with or without phentolamine was used to study alpha-AR binding. Chronic infusion of NE induced a greater downregulation of beta 2-AR compared with beta 1-AR in all regions studied, including atrial and ventricular myocytes, coronary arterioles, and connective tissue. An 18% loss of beta 1-AR was seen only in atrial myocytes; beta 1-AR density actually increased 28% in ve...Continue Reading

Citations

Sep 20, 2000·American Journal of Physiology. Heart and Circulatory Physiology·Z NagykaldiB Szabo
Feb 28, 2018·American Journal of Physiology. Endocrinology and Metabolism·Candace M RenoSimon J Fisher
Oct 3, 2019·American Journal of Physiology. Cell Physiology·Simon P WellsJames R Bell

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