Characterization of effects of endothelin-1 on the L-type Ca2+ current in human atrial myocytes

2001 ◽  
Vol 281 (2) ◽  
pp. H764-H773 ◽  
Author(s):  
Christophe Boixel ◽  
Sylvie Dinanian ◽  
Loîc Lang-Lazdunski ◽  
Jean-Jacques Mercadier ◽  
Stephane N. Hatem
Keyword(s):  
Inhibitory Effect ◽  
Signal Transduction Pathways ◽  
Intracellular Camp ◽  
Atrial Myocytes ◽  
Camp Concentration ◽  
Initial Current ◽  
Human Atrial Myocytes ◽  
Endothelin 1 ◽  
Intracellular Camp Concentration

The effects of endothelin-1 (ET-1) on the L-type Ca2+ current ( I Ca) were examined in whole cell patch-clamped human atrial myocytes. Depending on the initial current density, ET-1 (10 nM) increased the amplitude of I Ca by 99 ± 7% or decreased it by 33 ± 2%. The stimulatory effect predominated on current of low density (2.3 ± 0.2 pA/pF), whereas I Ca of higher density (5.8 ± 0.3 pA/pF) was inhibited by ET-1. After I Castimulation by 1 μM isoproterenol, ET-1 always inhibited the current by 32 ± 7% ( P < 0.05), an effect that was suppressed by pretreating myocytes with pertussis toxin. Atrial natriuretic peptide (ANP) inhibited I Ca (41 ± 3%) by reducing intracellular cAMP concentration. In ANP-treated myocytes, the stimulatory effect of ET-1 on I Capredominated (52 ± 7%). The inhibitory effect of ET-1 on I Ca was blocked by the ETAantagonist BQ-123, whereas the stimulatory effect was suppressed by the ETB agonist BQ-788. We conclude that ET-1 has opposite effects on I Ca depending on the baseline amplitude of current, and both subtype ET receptors are implicated in the signal transduction pathways.

scholarly journals Control of cyclic AMP concentration in bovine endometrial stromal cells by arachidonic acid

Reproduction ◽  
2007 ◽  
Vol 133 (5) ◽  
pp. 1017-1026 ◽  
Author(s):  
Z Cheng ◽  
E L Sheldrick ◽  
E Marshall ◽  
D C Wathes ◽  
D R E Abayasekara ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Cyclic Amp ◽  
Stromal Cells ◽  
Inhibitory Effect ◽  
Intracellular Camp ◽  
Dibutyryl Camp ◽  
Camp Concentration ◽  
Endometrial Stromal Cells ◽  
Kinase C ◽  
Intracellular Camp Concentration

Second messenger signalling through cyclic AMP (cAMP) plays an important role in the response of the endometrium to prostaglandin (PG) E2during early pregnancy. Arachidonic acid, which is a by-product of the luteolytic cascade in ruminants, is a potential paracrine signal from the epithelium to the stroma. We investigated the effects of arachidonic acid on the response of the stroma to PGE2. cAMP was measured in bovine endometrial stromal cells treated with agents known to activate or inhibit adenylyl cyclase, protein kinase C (PKC) or phosphodiesterase (PDE). PGE2increased the intracellular cAMP concentration within 10 min, and this effect was attenuated by arachidonic acid and the PKC activator, 4β-phorbol myristate acetate (PMA). The inhibitory effect of arachidonic acid on PGE2-induced cAMP accumulation was prevented by the PKC inhibitor, RO318425, and was absent in cells in which PKC had been downregulated by exposure to PMA for 24 h. The effect of arachidonic acid was also prevented by the PDE inhibitor, 3-isobutyl-1-methylxanthine. Arachidonic acid was shown by immunoblotting to prevent induction of cyclooxygenase-2 by PGE2, forskolin or dibutyryl cAMP. The results indicate that arachidonic acid activates PDE through a mechanism involving PKC, counteracting a rise in intracellular cAMP in response to PGE2. The data suggest that arachidonic acid antagonizes PGE2signalling through cAMP in the bovine endometrium, possibly acting to ensure a rapid return to oestrus in the case of failure of the maternal recognition of pregnancy.

P2869Role of PDE8 in cAMP dynamics in human atrial fibrillation

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
N Grammatika Pavlidou ◽  
S Pecha ◽  
H Reichenspurner ◽  
T Christ ◽  
V O Nikolaev ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Ventricular Myocytes ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Membrane Receptors ◽  
Intracellular Camp ◽  
Atrial Myocytes ◽  
Human Atrial Myocytes ◽  
Intracellular Compartments ◽  
Camp Levels

Abstract Background Cardiac arrhythmias, such as atrial fibrillation (AF), are often related to remodeling of membrane receptors and alterations in cAMP-dependent regulation of Ca2+ handling mechanisms. For instance, decreased L-type calcium current (ICa,L) density but upregulated RyR2 are major hallmarks of AF. These inhomogeneous AF-associated changes of protein phosphorylation point to a local regulation of PKA activity within these intracellular compartments. Local cAMP compartmentation and the role of phosphodiesterase (PDEs) have ben extensively studied in ventricular myocytes from animals. However, only a few studies have evaluated the contribution of PDEs to the pathophysiology of AF and the reason for the persistent AF-associated hypophosphorylation of the L-type calcium channel (LTCC) is currently unknown. The aim of this study was to investigate whether a change in the expression level of PDE8 in human atrium may affects cAMP nearby LTCC promoting the reduction of the ICa,L observed in persistent AF. Methods Atrial myocytes were isolated from tissue of 47 patients in sinus rhythm (SR) and with AF. Cells were then transfect with an adenovirus (Epac1-camps or pm-Epac1-camps) in order to express the (cytosolic or membrane, respectively) FRET-based cAMP sensor and cultured during 48 hours. Föster-resonance energy transfer (FRET) was used to measure cAMP in 232 isolated human atrial myocytes. Ro-20-1724 (10 μM), Cilostamide (1 μM) and PF-04957325 (30 nM) and IBMX (100 μM) were used as PDE4, PDE3, PDE8 and non-selective phosphodiesterases (PDEs) inhibitor respectively. Results Effects of PDE4 and especially PDE3 inhibition on cytosolic [cAMP] are reduced in AF. Pharmacological PDE8 inhibition induces only a small increase in basal intracellular [cAMP] in AF but it showed a big synergic effect when PDE4 was inhibit at the same time. By contrast, PDE8 inhibition dramatically increased basal [cAMP] in the subsarcolemmal compartment in AF while PDE3 or PDE4 inhibition had a smaller effect that didn't change between SR and AF. Conclusions PDE8 controls basal cytosolic cAMP levels in human atrial myocytes from patients with persistent AF while PDE3 effects tends to be reduced in these patients. Furthermore, PDE8 is the main PDE in controlling cAMP levels at the membrane in persistent AF. Thus, our study may provide a clue for the reported reduction of the ICa,L in persistent AF.

scholarly journals Antagonism by dibutyryl adenosine cyclic 3',5'-monophosphate and testololactone of concanavalin A capping.

1975 ◽  
Vol 66 (2) ◽  
pp. 392-403 ◽  
Author(s):  
B Storrie
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Cytochalasin B ◽  
Cold Treatment ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Con A ◽  
Cell Rounding ◽  
Intracellular Camp Concentration

Exposure of CHO-K1 cells in vitro to dibutyryl adenosine cyclic 3',5'-monophosphate (DBcAMP) plus testololactone produces a rapid, reversible antagonism of ligand-induced collection of initially dispersed concanavalin A (Con A) binding sites into a caplike mass. Morphologically, as Con A capping occurs, the cells become less spread and then round completely. With prolonged Con A exposure, cells cultured in either the absence or the presence of DBcAMP plus testololactone cap and round. Capping is blocked by cold treatment and respiratory inhibitors. Colcemid at concentrations greater than 1 muM promotes both Con A capping and cell rounding. Cytochalasin B at similar concentrations inhibits both capping and cell rounding. Treatment of cells with Con A has little effect on intracellular cAMP concentration. Possible mechanisms by which cAMP may modulate the movement of Con A binding sites are discussed.

Regulation of the TRPC1 channel by endothelin-1 in human atrial myocytes

Heart Rhythm ◽  
2019 ◽  
Vol 16 (10) ◽  
pp. 1575-1583
Author(s):  
Kai Zhang ◽  
Wei-Yin Wu ◽  
Gang Li ◽  
Yan-Hui Zhang ◽  
Yong Sun ◽  
...  
Keyword(s):  
Atrial Myocytes ◽  
Human Atrial Myocytes ◽  
Endothelin 1 ◽  
Trpc1 Channel

cAMP targeting of p38 MAP kinase inhibits thrombin-induced NF-κB activation and ICAM-1 expression in endothelial cells

2004 ◽  
Vol 287 (5) ◽  
pp. L1017-L1024 ◽  
Author(s):  
Arshad Rahman ◽  
Khandaker N. Anwar ◽  
Mohd. Minhajuddin ◽  
Kaiser M. Bijli ◽  
Kamran Javaid ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
P38 Mapk ◽  
Transcriptional Activity ◽  
Umbilical Vein ◽  
P38 Map Kinase ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Binding Function ◽  
Umbilical Vein Endothelial Cells ◽  
Intracellular Camp Concentration

We investigated the mechanisms by which elevated intracellular cAMP concentration inhibits the thrombin-induced ICAM-1 expression in endothelial cells. Exposure of human umbilical vein endothelial cells to forskolin or dibutyryl cAMP, which increase intracellular cAMP by separate mechanisms, inhibited the thrombin-induced ICAM-1 expression. This effect of cAMP was secondary to inhibition of NF-κB activity, the key regulator of thrombin-induced ICAM-1 expression in endothelial cells. The action of cAMP occurred downstream of IκBα degradation and was independent of NF-κB binding to the ICAM-1 promoter. We observed that cAMP interfered with thrombin-induced phosphorylation of NF-κB p65 (RelA) subunit, a crucial event promoting the activation of the DNA-bound NF-κB. Because p38 MAPK can induce transcriptional activity of RelA/p65 without altering the DNA binding function of NF-κB, we addressed the possibility that cAMP antagonizes thrombin-induced NF-κB activity and ICAM-1 expression by preventing the activation of p38 MAPK. We observed that treating cells with forskolin blocked the activation of p38 MAPK, and inhibition of p38 MAPK interfered with phosphorylation of RelA/p65 induced by thrombin. Our data demonstrate that increased intracellular cAMP concentration in endothelial cells prevents thrombin-induced ICAM-1 expression by inhibiting p38 MAPK activation, which in turn prevents phosphorylation of RelA/p65 and transcriptional activity of the bound NF-κB.

scholarly journals Ascorbic acid is a regulator of the intracellular cAMP concentration: Old molecule, new functions?

FEBS Letters ◽  
2008 ◽  
Vol 582 (25-26) ◽  
pp. 3614-3618 ◽  
Author(s):  
F. Kaya ◽  
S. Belin ◽  
Gr. Diamantidis ◽  
M. Fontes
Keyword(s):  
Ascorbic Acid ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Intracellular Camp Concentration

scholarly journals Electrophysiological Characterization of Isolated Human Atrial Myocytes Exposed to Tegaserod

2009 ◽  
Author(s):  
Silvia Suffredini ◽  
Elisabetta Cerbai ◽  
Gabriele Giunti ◽  
Mohamed El Mouelhi ◽  
Hans-Jürgen Pfannkuche ◽  
...  
Keyword(s):  
Atrial Myocytes ◽  
Human Atrial Myocytes ◽  
Electrophysiological Characterization

Cl−-dependent secretory mechanisms in isolated rat bile duct epithelial units

2001 ◽  
Vol 281 (2) ◽  
pp. G438-G446 ◽  
Author(s):  
Satish K. Singh ◽  
Albert Mennone ◽  
Alessandro Gigliozzi ◽  
Flavia Fraioli ◽  
James L. Boyer
Keyword(s):  
Bile Duct ◽  
Intrahepatic Bile Duct ◽  
Fluid Secretion ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Uptake Pathway ◽  
Duct Epithelium ◽  
Bile Duct Epithelium ◽  
Rat Bile ◽  
Intracellular Camp Concentration

Cholangiocytes absorb and secrete fluid, modifying primary canalicular bile. In several Cl−-secreting epithelia, Na+-K+-2Cl− cotransport is a basolateral Cl− uptake pathway facilitating apical Cl− secretion. To determine if cholangiocytes possess similar mechanisms independent of CO2/HCO[Formula: see text], we assessed Cl−-dependent secretion in rat liver isolated polarized bile duct units (IBDUs) by using videomicroscopy. Without CO2/HCO[Formula: see text], forskolin (FSK) stimulated secretion entirely dependent on Na+ and Cl−and inhibited by Na+-K+-2Cl−inhibitor bumetanide. Carbonic anhydrase inhibitor ethoxyzolamide had no effect on FSK-stimulated secretion, indicating negligible endogenous CO2/HCO[Formula: see text] transport. In contrast, FSK-stimulated secretion was inhibited ∼85% by K+ channel inhibitor Ba2+ and blocked completely by bumetanide plus Ba2+. IBDU Na+-K+-2Cl− cotransport activity was assessed by recording intracellular pH during NH4Cl exposure. Bumetanide inhibited initial acidification rates due to NH[Formula: see text] entry in the presence and absence of CO2/HCO[Formula: see text]. In contrast, when stimulated by FSK, a 35% increase in Na+-K+-2Cl− cotransport activity occurred without CO2/HCO[Formula: see text]. These data suggest a cellular model of HCO[Formula: see text]-independent secretion in which Na+-K+-2Cl−cotransport maintains high intracellular Cl−concentration. Intracellular cAMP concentration increases activate basolateral K+ conductance, raises apical Cl−permeability, and causes transcellular Cl− movement into the lumen. Polarized IBDU cholangiocytes are capable of vectorial Cl−-dependent fluid secretion independent of HCO[Formula: see text]. Bumetanide-sensitive Na+-K+-2Cl− cotransport, Cl−/HCO[Formula: see text] exchange, and Ba2+-sensitive K+ channels are important components of stimulated fluid secretion in intrahepatic bile duct epithelium.

Modulation of ionic permeability in a nonpolarized cell: effect of cAMP

1989 ◽  
Vol 257 (6) ◽  
pp. F985-F993
Author(s):  
R. D. London ◽  
M. S. Lipkowitz ◽  
R. H. Sinert ◽  
R. G. Abramson
Keyword(s):  
Normal Subjects ◽  
Disulfonic Acid ◽  
Intracellular Camp ◽  
Red Cell ◽  
Relative Permeabilities ◽  
Camp Concentration ◽  
Chloride Permeability ◽  
Polarized Epithelia ◽  
Disulfonic Stilbene ◽  
Intracellular Camp Concentration

To evaluate whether adenosine 3',5'-cyclic monophosphate (cAMP) modulates ionic permeabilities of nonpolarized cells, as reported in diverse polarized epithelia, relative ionic permeabilities were determined in human red cell ghosts by means of the potential-sensitive fluorescent probe 3,3'-dipropylthiadicarbocyanine iodide. Relative ionic chloride permeability (PCl/PK), but not PNa/PK, was significantly increased in ghosts prepared from normal red blood cells (RBCs) exposed to cAMP analogues or forskolin, with the latter at a concentration that significantly increased intracellular cAMP concentration. As basal RBC cAMP concentrations of untreated uremic subjects were also increased, relative permeabilities of ghosts and unstimulated RBC cAMP concentrations were compared in normal, uremic, and dialyzed subjects, PCl/PK was significantly increased in uremic compared with normal subjects; PNa/PK was not altered. PCl/PK and RBC cAMP concentrations were indistinguishable in normal and dialyzed subjects. Neither the kinetics nor number of Cl(-)-HCO3- antiporters, assessed with the pH-sensitive probe acridine orange and the disulfonic stilbene 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, respectively, were altered in uremic cells. These studies suggest that cAMP modulates ionic chloride permeability via increased chloride conductance of each Cl(-)-HCO3- antiporter or by activation/opening of new or existing channels in RBC membranes.

Dysregulation of intracellular pH is a cause of impaired capacitation in Slc22a14-deficient mice

Reproduction ◽  
2021 ◽  
Author(s):  
Momoe Ito ◽  
Masato Unou ◽  
Toshiya Higuchi ◽  
Shuhei So ◽  
Masahiko Ito ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Critical Role ◽  
Fertilization Rate ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Vitro Fertilization ◽  
Solute Carrier ◽  
Deficient Mice ◽  
Intracellular Camp Concentration

Solute carrier 22a member 14 (SLC22A14) plays a critical role in male infertility in mice. We previously revealed that one of the causes of infertility is impaired capacitation. However, the molecular mechanism remained unclear. Here, we show that the influx of HCO3–, a trigger of capacitation, is impaired and intracellular pH is decreased in the sperm of Slc22a14 knockout (KO) mice. While intracellular cAMP concentration did not increase during capacitation in Slc22a14 KO spermatozoa, HCO3–-dependent soluble adenylate cyclase activity was normal, and the addition of 8-bromo cAMP rescued the decreased protein tyrosine phosphorylation. In addition, the intracellular pH of Slc22a14 KO sperm was lower than that of wild-type sperm and did not increase after the addition of HCO3–. Although its relationship to the regulation of intracellular pH is unknown, TMEM225, a possible protein phosphatase inhibitor, was found to be decreased in Slc22a14 KO sperm. The decreased in vitro fertilization rate of Slc22a14 KO sperm was partially rescued by an increase in the intracellular pH (pHi) and the addition of 8-bromo cAMP. These results suggest that SLC22A14 is involved in capacitation through the regulation of HCO3– transport and pHi.

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