MYOCARDIAL BETA-ADRENERGIC RECEPTORS FROM ADRENALECTOMIZED RATS:IMPAIRED FORMATION OF HIGH-AFFINITY AGONIST-RECEPTOR COMPLEXES

Endocrinology ◽  
1981 ◽  
Vol 108 (2) ◽  
pp. 720-722 ◽  
Author(s):  
ALBERT O. DAVIES ◽  
ANDRE DE. LEAN ◽  
ROBERT J. LEFKOWITZ
Keyword(s):  
Adrenergic Receptors ◽  
Beta Adrenergic Receptors ◽  
Beta Adrenergic ◽  
Receptor Complexes ◽  
High Affinity

Characterization of beta-adrenergic receptors in cultured bovine tracheal gland cells

1989 ◽  
Vol 256 (2) ◽  
pp. C310-C314 ◽  
Author(s):  
J. M. Madison ◽  
C. B. Basbaum ◽  
J. K. Brown ◽  
W. E. Finkbeiner
Keyword(s):  
Binding Sites ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Rank Order ◽  
Beta Adrenergic Receptors ◽  
Binding Studies ◽  
Beta Adrenergic ◽  
High Affinity ◽  
Gland Cells ◽  
Beta 2

We characterized the beta-adrenergic receptors that mediate secretory responses to isoproterenol in cultured bovine tracheal submucosal gland cells. Previous studies have shown that these cells have morphological and biochemical features characteristic of serous cells. Isoproterenol, epinephrine, and norepinephrine each stimulated the secretion of 35SO4-labeled macromolecules from these cultured serous cells with a rank order of potency (isoproterenol greater than epinephrine greater than norepinephrine) consistent with the presence of beta 2-adrenergic receptors. These functional studies were supported by radioligand-binding studies using [I125]-iodocyanopindolol (125I-CYP) to identify beta-adrenergic receptors. 125I-CYP binding to membrane particulates prepared from cultured serous cells was saturable and of high affinity (equilibrium dissociation constant 20 +/- 3 pM; mean +/- SE, n = 6) and was antagonized stereoselectively by propranolol. Adrenergic agonists competed for 125I-CYP-binding sites with a rank order of potency characteristic of the beta 2-adrenergic receptor subtype. A specific beta 2-adrenergic receptor antagonist, ICI 118.551, competed for a single class of 125I-CYP-binding sites with high affinity (inhibition constant 1.8 +/- 0.3 nM, n = 3). We concluded that the secretory response of cultured tracheal gland cells to isoproterenol is a response mediated by beta-adrenergic receptors of the beta 2 subtype.

Visualization of high- and low-affinity beta-adrenergic receptors in rat lung: upregulation by chronic hypoxia

1993 ◽  
Vol 265 (4) ◽  
pp. L389-L394 ◽  
Author(s):  
D. J. Birnkrant ◽  
P. B. Davis ◽  
P. Ernsberger
Keyword(s):  
Binding Sites ◽  
Functional Significance ◽  
Adrenergic Receptors ◽  
Chronic Hypoxia ◽  
Lung Parenchyma ◽  
Guanine Nucleotide ◽  
Rat Lung ◽  
Beta Adrenergic Receptors ◽  
Beta Adrenergic ◽  
High Affinity

Chronic hypoxia induces a hyperadrenergic state which down-regulates beta-adrenergic receptors (beta-AR) in the heart. We visualized lung beta-AR binding sites after adaptation to chronic hypoxia by autoradiography of whole lung sections labeled with 50 pM 125I-labeled pindolol. A low concentration of agonist (32 nM isoproterenol) selectively masked beta-ARs with high affinity for agonists. Total specific beta-AR binding increased twofold with hypoxia. In both the control and hypoxic lung sections, 60–70% of the beta-ARs were in a high-affinity state, which could be reversed by guanine nucleotide. Autoradiography revealed a high density of high- and low-affinity beta-AR sites in lung parenchyma, predominantly involving alveolar walls, but also the walls of airways and blood vessels. The distribution of high- and low-affinity beta-AR within the lung was qualitatively identical. Hypoxia increased beta-AR binding without affecting its distribution. The majority of the additional beta-ARs induced during adaptation to chronic hypoxia are in the high-affinity state, and are thus of probable functional significance.

Effects of coronary arterial reperfusion on beta-adrenergic receptor-adenylyl cyclase coupling

1993 ◽  
Vol 264 (1) ◽  
pp. H196-H204 ◽  
Author(s):  
D. E. Vatner ◽  
K. Kiuchi ◽  
W. T. Manders ◽  
S. F. Vatner
Keyword(s):  
Adenylyl Cyclase ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Cyclase Activity ◽  
Receptor Density ◽  
Beta Adrenergic Receptors ◽  
Adenylyl Cyclase Activity ◽  
Beta Adrenergic Receptor ◽  
Beta Adrenergic ◽  
High Affinity

The effects of 1 h of coronary arterial occlusion (CAO) followed by 15 min reperfusion (CAR) were examined in nine conscious dogs. Ischemia was verified by decreased regional blood flow (radioactive microspheres) and loss of systolic regional wall motion in the ischemic zone. beta-Adrenergic receptor density assessed by 125I-labeled cyanopindolol binding in a crude membrane fraction tended to decrease but was not significantly different. However, adenylyl cyclase activity and the guanine nucleotide stimulatory protein (Gs) were reduced in ischemic subendocardium compared with nonischemic subendocardium. The fraction of beta-adrenergic receptors binding agonist with high affinity increased in ischemic subendocardial and subepicardial layers. Compared with prior data in experiments with 1 h CAO without CAR, the increase in beta-adrenergic receptor density that occurs with myocardial ischemia is rapidly reversed with CAR of 15 min duration, while the decreased fraction of receptors binding agonist with high affinity was reversed to an increase in high-affinity receptors. The global decreases in adenylyl cyclase and Gs, which have been observed with simple CAO, persist but are observed selectively in the previously ischemic subendocardium after CAR. Thus both CAO and CAR affect beta-adrenergic receptors and adenylyl cyclase differently. During CAR, increased numbers of beta-adrenergic receptors binding agonist with high affinity occur potentially as a compensatory mechanism in the face of persistent reductions in adenylyl cyclase activity and Gs.

scholarly journals Loss of high affinity cardiac beta adrenergic receptors in dogs with heart failure.

1985 ◽  
Vol 76 (6) ◽  
pp. 2259-2264 ◽  
Author(s):  
D E Vatner ◽  
S F Vatner ◽  
A M Fujii ◽  
C J Homcy
Keyword(s):  
Heart Failure ◽  
Adrenergic Receptors ◽  
Beta Adrenergic Receptors ◽  
Beta Adrenergic ◽  
High Affinity
Sign in / Sign up

Export Citation Format

Share Document