Abstract:
:The potassium selective, inward rectifier current (IK1) is known to be responsible for maintaining the resting membrane potential of quiescent ventricular myocytes. However, the contribution of this current to the different phases of the cardiac action potential has not been adequately established. In the present study, we have used the action potential clamp (APC) technique to characterize the dynamic changes of a cesium-sensitive (i.e., Ik1) current which occur during the action potential. Our results show that (a) Ik1 is present during depolarization, as well as in the final phase of repolarization of the cardiac action potential. (b) The current reaches the zone of inward-going rectification before the regenerative action potential ensues. (c) The maximal outward current amplitude during repolarization is significantly lower than during depolarization, which supports the hypothesis that in adult guinea pig ventricular myocytes, Ik1 rectification is accentuated during the action potential plateau. Our results stress the importance of Ik1 in the modulation of cell excitability in the ventricular myocyte.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Ibarra J,Morley GE,Delmar Mdoi
10.1016/S0006-3495(91)82187-7subject
Has Abstractpub_date
1991-12-01 00:00:00pages
1534-9issue
6eissn
0006-3495issn
1542-0086pii
S0006-3495(91)82187-7journal_volume
60pub_type
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