scholarly journals Kinetic analysis of internalization, recycling and redistribution of atrial natriuretic factor-receptor complex in cultured vascular smooth-muscle cells. Ligand-dependent receptor down-regulation

1992 ◽  
Vol 288 (1) ◽  
pp. 55-61 ◽  
Author(s):  
K N Pandey
Keyword(s):  
Smooth Muscle ◽  
Cell Surface ◽  
Atrial Natriuretic Factor ◽  
Dependent Manner ◽  
Receptor Complex ◽  
Down Regulation ◽  
Surface Receptors ◽  
Natriuretic Factor ◽  
Metabolic Degradation ◽  
Atrial Natriuretic

The kinetics of internalization, sequestration and metabolic degradation of atrial natriuretic factor (ANF)-receptor complex were studied in rat thoracic aortic smooth-muscle (RTASM) cells. These parameters were directly determined by measuring 125I-ANF binding to total, intracellular and cell-surface receptors. Pretreatment of cells with the lysosomotropic agent chloroquine and the energy depleter dinitrophenol led to an increase in the intracellular 125I-ANF radioactivity. After 60 min incubation at 37 degrees C, cell-associated 125I-ANF radioactivity fell rapidly in chloroquine-treated cells (> 85%) compared with the controls (< 45%). 125I-ANF radioactivity increased to a peak of 65% of the initial level within 15 min in chloroquine-treated cells compared with only 22% in the control cells. During the initial incubation period at 37 degrees C, chloroquine inhibited the release of both intact and degraded 125I-ANF in a time-dependent manner. However, at later incubation times, the effect of chloroquine was diminished and release of both degraded and intact ligand was resumed. Extracellular unlabelled ANF did not affect the release of degraded 125I-ANF but it accelerated the release of intact ANF by a retroendocytotic mechanism. After the endocytosis, about 30-40% of ANF receptors were restored to the cell surface from the internalized pool of receptors. The restoration was blocked by chloroquine or dinitrophenol but not by cycloheximide. Exposure of RTASM cells to unlabelled ANF resulted in a time- and concentration-dependent loss of ANF receptors. Unlabelled ANF (10 nM) induced a loss of more than 52% of 125I-ANF binding, and a complete loss occurred at micromolar concentrations. It is inferred that ANF-induced down-regulation of its receptor resulted primarily from an increased rate in internalization and metabolic degradation of ligand-receptor complex by receptor-mediated endocytotic mechanisms.

scholarly journals Differential internalization and processing of atrial-natriuretic-factor B and C receptor in PC12 cells

1991 ◽  
Vol 276 (2) ◽  
pp. 493-497 ◽  
Author(s):  
A Rathinavelu ◽  
G E Isom
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Pc12 Cells ◽  
Atrial Natriuretic Factor ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Surface Binding ◽  
Down Regulation ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

PC12 cells express two atrial-natriuretic-factor-(ANF)-receptor subtypes with molecular masses of 130,000 (B receptor) and 70,000 (C receptor). The B-receptor subtype constitutes 65% of the cell-surface receptor population, and the remaining 35% are C receptors as determined by saturation binding studies in the presence of C-ANF, a C-receptor-selective analogue. ANF-(99-126)-peptide [ANF(99-126)], which can bind to both B- and C-receptor subtypes, was rapidly internalized into the cells after incubation at 37 degrees C. Internalization of 125I-ANF(99-126) was used as an index of the receptor-mediated endocytosis and to quantify receptor internalization. In the presence of a saturating concentration of C-ANF, receptor-mediated internalization of 125I-ANF(99-126) was reduced by 24%, indicating B receptor mediate 76% of ligand internalization. Incubation of cells with 10 microM-ANF at 37 degrees C down-regulated both receptor subtypes as reflected by decreased surface binding. Time-dependent studies suggest that B- and C-receptor subtypes undergo differential down-regulation. Incubation of down-regulated cells for 120 min in ANF-free medium produced a recovery of 35% of the original cell-surface binding. Affinity cross-linking of 125I-ANF to the receptors on the plasma membrane in re-incubated (up-regulated) cells demonstrated expression of predominantly the B-receptor subtype. Monensin blocked 72% of receptor up-regulation, whereas cycloheximide inhibited 43%, suggesting an active recycling mechanism involved in mediating up-regulation of the B receptors. The present study demonstrates a rapid internalization and intracellular recycling mechanism for B receptors in PC12 cells. C receptors also undergo internalization and down-regulation, but recycling of this receptor subtype into the plasma membrane occurs at a lower rate and to a lesser extent than is the case for the B receptor.

scholarly journals CHARACTERIZATION OF ATRIAL NATRIURETIC FACTOR RECEPTORS IN ADRENAL CORTEX, VASCULAR SMOOTH MUSCLE AND ENDOTHELIAL CELLS BY AFFINITY LABELING

1986 ◽  
Vol 7 (1) ◽  
pp. 35-38 ◽  
Author(s):  
MASASHI SHINJO ◽  
YUKIO HIRATA ◽  
HIROMI HAGIWARA ◽  
FUMIAKI AKIYAMA ◽  
KAZUO MURAKAMI ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Adrenal Cortex ◽  
Atrial Natriuretic Factor ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

Influence of atrial natriuretic factor on uptake, intracellular distribution, and release of norepinephrine in rat adrenal medulla

1993 ◽  
Vol 71 (3-4) ◽  
pp. 195-200 ◽  
Author(s):  
M. S. Vatta ◽  
L. G. Bianciotti ◽  
B. E. Fernández
Keyword(s):  
Adrenal Medulla ◽  
Atrial Natriuretic Factor ◽  
Muscle Tone ◽  
Intracellular Distribution ◽  
Dependent Manner ◽  
High Potassium ◽  
Norepinephrine Uptake ◽  
Arterial Blood ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

Several studies have demonstrated that atrial natriuretic factor can bind to adrenal medulla cells. Furthermore, atrial natriuretic factor immunoreactivity has been identified in chromaffin cells. The aim of the present work was to investigate atrial natriuretic factor effects on the uptake, intracellular distribution, and release of norepinephrine in the rat adrenal medulla. Results showed that 100 nM atrial natriuretic factor induced a rapid increase of norepinephrine uptake during the first minute of the incubation period. This increase was maintained for up to 60 min. In addition, only neuronal norepinephrine uptake was increased by the natriuretic factor; non-neuronal norepinephrine uptake was unaltered. Atrial natriuretic factor modified the intracellular distribution of the amine store: the granular fraction of norepinephrine increased, while the cytosolic fraction decreased. On the other hand, different concentrations (10, 50, and 100 nM) of the atrial factor decreased spontaneous [3H]norepinephrine output in a concentration-dependent manner. Furthermore, atrial natriuretic factor (10 nM) also reduced high potassium solution evoked secretion of norepineprhine. These results suggest that atrial natriuretic factor modulates sympathetic activity in the rat adrenal medulla. These effects of atrial natriuretic factor may be related to the catecholamine peripheral mechanism involved in the regulation of arterial blood pressure, smooth muscle tone, metabolic activity, etc.Key words: adrenal medulla, atrial natriuretic factor, intracellular norepinephrine distribution, norepinephrine release, norepineprhine uptake.

Sign in / Sign up

Export Citation Format

Share Document