scholarly journals The alpha-adrenergic stimulation of atrial natriuretic factor expression in cardiac myocytes requires calcium influx, protein kinase C, and calmodulin-regulated pathways

1991 ◽  
Vol 266 (24) ◽  
pp. 15910-15916 ◽  
Author(s):  
C.A. Sei ◽  
C.E. Irons ◽  
A.B. Sprenkle ◽  
P.M. McDonough ◽  
J.H. Brown ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cardiac Myocytes ◽  
Atrial Natriuretic Factor ◽  
Calcium Influx ◽  
Adrenergic Stimulation ◽  
Kinase C ◽  
Natriuretic Factor ◽  
Factor Expression ◽  
Stimulation Of

scholarly journals Stimulation of phosphoinositide metabolism in hamster brown adipocytes exposed to α1-adrenergic agents and its inhibition with phorbol esters

1986 ◽  
Vol 236 (3) ◽  
pp. 757-764 ◽  
Author(s):  
R J Schimmel ◽  
D Dzierzanowski ◽  
M E Elliott ◽  
T W Honeyman
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Time Course ◽  
Early Event ◽  
Phosphoinositide Metabolism ◽  
Adrenergic Stimulation ◽  
Brown Adipocytes ◽  
Adrenergic Agents ◽  
Kinase C ◽  
Stimulation Of

The present experiments were undertaken to investigate the role of the phosphoinositides phosphatidylinositol 4-phosphate (PtdIns-4-P) and phosphatidylinositol 4,5-biphosphate (PtdIns-4,5-P2) in the alpha 1-adrenergic stimulation of respiration in isolated hamster brown adipocytes. Exposure of isolated brown adipocytes to the alpha-adrenergic-receptor agonist phenylephrine provoked a breakdown of 30-50% of the PtdIns-4-P and PtdIns-4,5-P2 after prelabelling of the cells with [32P]Pi. Coincident with the breakdown of phosphoinositides was an accumulation of labelled phosphatidic acid, which continued for the duration of the cell incubation. The time course of phosphoinositide breakdown was defined more precisely by pulse-chase experiments. Under these conditions, phenylephrine caused radioactivity in phosphatidylinositol, PtdIns-4-P and PtdIns-4,5-P2 to fall by more than 50% within 30 s and to remain at the depressed value for the duration of the incubation (10 min). This phospholipid response to alpha-adrenergic stimulation was blocked by exposure of the cells to phorbol 12-myristate 13-acetate (PMA); likewise phenylephrine stimulation of respiration was prevented by PMA. beta-Adrenergic stimulation of respiration and inhibition of respiration by 2-chloroadenosine and insulin were, however, unaffected by treatment with PMA. On the assumption that PMA is acting in these cells as an activator of protein kinase C, these results suggest the selective interruption of alpha-adrenergic actions in brown adipocytes by activated protein kinase C. These findings suggest that breakdown of phosphoinositides is an early event in alpha-adrenergic stimulation of brown adipocytes which may be important for the subsequent stimulation of respiration. The results from the pulse-chase studies also suggest, however, that phenylephrine-stimulated breakdown of inositol phospholipids is a short-lived event which does not appear to persist for the entire period of exposure to the alpha 1-adrenergic ligand.

scholarly journals An activator of protein kinase C (phorbol dibutyrate) attenuates atrial-natriuretic-factor-stimulated cyclic GMP accumulation in smooth-muscle cells

1987 ◽  
Vol 244 (2) ◽  
pp. 481-484 ◽  
Author(s):  
P Nambi ◽  
M Whitman ◽  
N Aiyar ◽  
F Stassen ◽  
S T Crooke
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Cyclic Gmp ◽  
Atrial Natriuretic Factor ◽  
Muscle Cells ◽  
Phorbol Dibutyrate ◽  
Kinase C ◽  
Natriuretic Factor

Rat thoracic aortic smooth-muscle cells (A-10; A.T.C.C. CRL 1476) displays a high density of vasopressin and atrial-natriuretic-factor (ANF) receptors and a low density of beta-adrenergic receptors. ANF stimulates cGMP (cyclic GMP) accumulation in a time- and dose-dependent fashion. Pretreatment of these cells with phorbol dibutyrate (PDBu), a known activator of protein kinase C, attenuated ANF-stimulated cGMP accumulation without affecting basal cGMP concentrations. This effect was concentration-dependent and was observed as early as 2 min after treatment. 4 alpha-Phorbol 12, 13-didecanoate (alpha PDD), which does not activate protein kinase C, did not inhibit the cGMP accumulation. PDBu pretreatment did not affect the density and affinity of ANF receptors. These data suggest that PDBu, presumably via activation of protein kinase C, might stimulate phosphorylation of a key regulatory protein in the ANF/cGMP pathway.

Alpha-adrenergic regulation of phosphoinositide metabolism and protein kinase C in isolated cardiac myocytes

1991 ◽  
Vol 260 (3) ◽  
pp. C635-C642 ◽  
Author(s):  
T. Kaku ◽  
E. Lakatta ◽  
C. Filburn
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cardiac Myocytes ◽  
Inositol Phosphates ◽  
Total Activity ◽  
Phosphoinositide Metabolism ◽  
Adrenergic Stimulation ◽  
Adrenergic Regulation ◽  
Kinase C ◽  
Isolated Cardiac Myocytes

alpha 1-Adrenergic regulation of phosphoinositide metabolism and protein kinase C translocation was studied in isolated rat cardiac myocytes. Exposure of [3H]inositol-labeled myocytes to norepinephrine in the presence of propranolol caused a dose-dependent increase in [3H]inositol phosphates. Norepinephrine also increased the level of membrane-associated protein kinase C from approximately 10% of total activity to 18%, with a dose response similar to that for generation of inositol phosphates. Depolarization of myocytes with 30 mM KCl had no effect on inositol phosphates or membrane-associated protein kinase C but potentiated the effect of submaximal norepinephrine on both parameters. The potentiation of protein kinase C translocation was amplified when extracellular Ca2+ was increased to 4 mM, resulting in membrane association of one-third of the total cellular activity. These data show that activation of protein kinase C occurs during alpha 1-adrenergic stimulation of cardiac myocytes and that elevation of intracellular Ca2+ amplifies this effect at least in part through increased phosphoinositide metabolism.

Alpha 1-adrenergic stimulation of Na-H exchange in cardiac myocytes

1992 ◽  
Vol 263 (5) ◽  
pp. C1096-C1102 ◽  
Author(s):  
M. A. Wallert ◽  
O. Frohlich
Keyword(s):  
Protein Kinase C ◽  
Steady State ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Ph Dependence ◽  
Adrenergic Stimulation ◽  
Adult Rat ◽  
Kinase C ◽  
Rat Heart Myocytes ◽  
Stimulation Of

The activation of Na-H exchange in adult rat heart myocytes was characterized in response to a phorbol ester (phorbol 12-myristate 13-acetate) and an alpha 1-adrenergic agonist [6-fluoronorepinephrine (6F-NE)]. Transport activation was assessed by determining the initial rate with which intracellular pH (pHi) was returned from an acid pulse and by following changes in steady-state pHi; pHi was determined by a pH-sensitive fluorescent dye. Both agonists shifted the intracellular pH dependence of Na-H exchange by 0.10-0.15 pH units in the alkaline direction. This shift was prevented by the presence of sphingosine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), inhibitors of protein kinase C. The agonists also alkalinized pHi at steady state. The alkalinization by 6F-NE was blocked by prazosin and H-7. This indicates that the adrenergic stimulation of cardiac Na-H exchange is mediated by an alpha 1-adrenergic mechanism and very likely involves the activation of protein kinase C.

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