Intracellular ADP activates ATP-sensitive K+ channels in vascular smooth muscle cells of the guinea pig portal vein

1993 ◽  
Vol 423-423 (1-2) ◽  
pp. 149-151 ◽  
Author(s):  
Dietmar Pfr�nder ◽  
Ion Anghelescu ◽  
Volker A. W. Kreye
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Portal Vein ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
K Channels

β-Adrenoceptor activation and PKA regulate delayed rectifier K+ channels of vascular smooth muscle cells

1998 ◽  
Vol 275 (2) ◽  
pp. H448-H459 ◽  
Author(s):  
E. Alejandro Aiello ◽  
A. Todd Malcolm ◽  
Michael P. Walsh ◽  
William C. Cole
Keyword(s):  
Signal Transduction ◽  
Smooth Muscle ◽  
Portal Vein ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Catalytic Subunit ◽  
Delayed Rectifier ◽  
Rabbit Portal Vein

Macroscopic 4-aminopyridine (4-AP)-sensitive, delayed rectifier K+ current of vascular smooth muscle cells is increased during β-adrenoceptor activation with isoproterenol via a signal transduction pathway involving adenylyl cyclase and cAMP-dependent protein kinase (PKA) (Aiello, E. A., M. P. Walsh, and W. C. Cole. Am. J. Physiol. 268 ( Heart Circ. Physiol. 37): H926–H934, 1995.). In this study, we identified the single delayed rectifier K+(KDR) channel(s) of rabbit portal vein myocytes affected by treatment with isoproterenol or the catalytic subunit of PKA. 4-AP-sensitive KDR channels of 15.3 ± 0.6 pS ( n = 5) and 14.8 ± 0.6 pS ( n = 5) conductance, respectively, were observed in inside-out (I-O) and cell-attached (C-A) membrane patches in symmetrical KCl recording conditions. The kinetics of activation (time constant of 10.7 ± 3.02 ms) and inactivation (fast and slow time constants of 0.3 and 2.5 s, respectively) of ensemble currents produced by these channels mimicked those reported for inactivating, 4-AP-sensitive whole cell KDR current of vascular myocytes. Under control conditions, the open probability ( NP o) of KDR channels of C-A membrane patches at −40 mV was 0.014 ± 0.005 ( n = 8). Treatment with 1 μM isoproterenol caused a significant, approximately threefold increase in NP o to 0.041 ± 0.02 ( P < 0.05). KDR channels of I-O patches exhibited rundown after ∼5 min, which was not affected by ATP (5 mM) in the bath solution. Treatment with the purified catalytic subunit of PKA (50 nM; 5 mM ATP) restored KDRchannel activity and caused NP o to increase from 0.011 ± 0.003 to 0.138 ± 0.03 ( P < 0.05; n = 11). These data indicate that small-conductance, 15-pS KDRchannels are responsible for inactivating the macroscopic delayed rectifier K+ current of rabbit portal vein myocytes and that the activity of these channels is enhanced by a signal transduction mechanism involving β-adrenoceptors and phosphorylation by PKA at a membrane potential consistent with that observed in the myocytes in situ.

scholarly journals EDHF: an update

2009 ◽  
Vol 117 (4) ◽  
pp. 139-155 ◽  
Author(s):  
Michel Félétou ◽  
Paul M. Vanhoutte
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Electrical Coupling ◽  
Muscle Cells ◽  
Therapeutic Interventions ◽  
K Channels ◽  
Acid Metabolites

The endothelium controls vascular tone not only by releasing NO and prostacyclin, but also by other pathways causing hyperpolarization of the underlying smooth muscle cells. This characteristic was at the origin of the term ‘endothelium-derived hyperpolarizing factor’ (EDHF). However, this acronym includes different mechanisms. Arachidonic acid metabolites derived from the cyclo-oxygenases, lipoxygenases and cytochrome P450 pathways, H2O2, CO, H2S and various peptides can be released by endothelial cells. These factors activate different families of K+ channels and hyperpolarization of the vascular smooth muscle cells contribute to the mechanisms leading to their relaxation. Additionally, another pathway associated with the hyperpolarization of both endothelial and vascular smooth muscle cells contributes also to endothelium-dependent relaxations (EDHF-mediated responses). These responses involve an increase in the intracellular Ca2+ concentration of the endothelial cells, followed by the opening of SKCa and IKCa channels (small and intermediate conductance Ca2+-activated K+ channels respectively). These channels have a distinct subcellular distribution: SKCa are widely distributed over the plasma membrane, whereas IKCa are preferentially expressed in the endothelial projections toward the smooth muscle cells. Following SKCa activation, smooth muscle hyperpolarization is preferentially evoked by electrical coupling through myoendothelial gap junctions, whereas, following IKCa activation, K+ efflux can activate smooth muscle Kir2.1 and/or Na+/K+-ATPase. EDHF-mediated responses are altered by aging and various pathologies. Therapeutic interventions can restore these responses, suggesting that the improvement in the EDHF pathway contributes to their beneficial effect. A better characterization of EDHF-mediated responses should allow the determination of whether or not new drugable targets can be identified for the treatment of cardiovascular diseases.

scholarly journals High blood pressure associates with the remodelling of inward rectifier K+channels in mice mesenteric vascular smooth muscle cells

2012 ◽  
Vol 590 (23) ◽  
pp. 6075-6091 ◽  
Author(s):  
Sendoa Tajada ◽  
Pilar Cidad ◽  
Alejandro Moreno-Domínguez ◽  
M. Teresa Pérez-García ◽  
José R. López-López
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
High Blood Pressure ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Inward Rectifier ◽  
K Channels

Both membrane stretch and fatty acids directly activate large conductance Ca2+ -activated K+ channels in vascular smooth muscle cells

FEBS Letters ◽  
1992 ◽  
Vol 297 (1-2) ◽  
pp. 24-28 ◽  
Author(s):  
Michael T. Kirber ◽  
Richard W. Ordway ◽  
Lucie H. Clapp ◽  
John V. Walsh ◽  
Joshua J. Singer
Keyword(s):  
Fatty Acids ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
K Channels ◽  
Membrane Stretch
Sign in / Sign up

Export Citation Format

Share Document