ISSN:
1432-1424
Keywords:
Sinoatrial node cell
;
Background current
;
Chloride channel
;
Angiotensin II
;
AT1 receptor
;
Protein kinase C
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Single sino-atrial cells from rabbit heart were voltage-clamped using the whole-cell configuration of the patch clamp technique under conditions in which most of the ionic and exchange currents known in pacemaker cardiac cells were minimized. Extracellular angiotensin II (AII) activated a time-independent background current. The current-voltage relation of this current showed an outward rectification. The reversal potential was −20 mV with 156 mm Cl− external solution and 54 mm Cl− internal solution. This reversal potential shifted with changes in the transmembrane Cl− gradient in the fashion expected for a chloride current. Anthracene-9-carboxylic acid and diphenylamine 2-carboxilic acid (chloride channels blockers) were found to be effective in blocking the AII-sensitive current. The linear segment of the current-voltage relation can be totally inhibited by the competitive AII-receptor (AT1) antagonist losartan and by the presence of intracellular protein kinase C inhibitor, whereas the outward rectification is only slightly changed. It is concluded that sino-atrial cells should contain protein-kinase-C-sensitive chloride channels which may be activated by angiotensin II via the stimulation of the AT1 receptors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00232903
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