Unknown

Dataset Information

0

A model of canine purkinje cell electrophysiology and Ca(2+) cycling: rate dependence, triggered activity, and comparison to ventricular myocytes.


ABSTRACT: Purkinje cells (Pcell) are characterized by different electrophysiological properties and Ca(2+) cycling processes than ventricular myocytes (Vcell) and are frequently involved in ventricular arrhythmias. Yet, the mechanistic basis for their arrhythmic vulnerability is not completely understood. The objectives were to: (1) characterize Pcell electrophysiology, Ca(2+) cycling, and their rate dependence; (2) investigate mechanisms underlying Pcell arrhythmogenicity; and compare Pcell and Vcell electrophysiology, Ca(2+) cycling, and arrhythmic properties. We developed a new mathematical model of Pcell. The Ca(2+) subsystem includes spatial organization and receptors distribution unique to Pcell. Results were: (1) in Pcell and Vcell, Na(+) accumulation via its augmentation of repolarizing I(NaK) dominates action potential duration adaptation and, in Pcell, I(NaL) contributes additional action potential duration shortening at short cycle length; (2) steep Pcell restitution is attributable to slow recovery of I(NaL); (3) biphasic Ca(2+) transients of Pcell reflect the delay between Ca(2+) release from junctional sarcoplasmic reticulum and corbular sarcoplasmic reticulum; (4) Pcell Ca(2+) alternans, unlike Vcell, can develop without inducing action potential alternans; (5) Pcell action potential alternans develops at a shorter cycle length than Vcell, with increased subcellular heterogeneity of Ca(2+) cycling attributable to refractoriness of Ca(2+) release from corbular sarcoplasmic reticulum and junctional sarcoplasmic reticulum; (6) greater Pcell vulnerability to delayed afterdepolarizations is attributable to higher sarcoplasmic reticulum Ca(2+) content and ionic currents that reduce excitation threshold and promote triggered activity; and (7) early after depolarizations generation in Pcell is mostly attributable to reactivation of I(NaL2), whereas I(CaL) plays this role in Vcell. Steeper rate dependence of action potential and Ca(2+) transients, central peripheral heterogeneity of Ca(2+) cycling, and distinct ion channel profile underlie greater arrhythmic vulnerability of Pcell compared to Vcell.

SUBMITTER: Li P 

PROVIDER: S-EPMC3143030 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

altmetric image

Publications

A model of canine purkinje cell electrophysiology and Ca(2+) cycling: rate dependence, triggered activity, and comparison to ventricular myocytes.

Li Pan P   Rudy Yoram Y  

Circulation research 20110512 1


Purkinje cells (Pcell) are characterized by different electrophysiological properties and Ca(2+) cycling processes than ventricular myocytes (Vcell) and are frequently involved in ventricular arrhythmias. Yet, the mechanistic basis for their arrhythmic vulnerability is not completely understood. The objectives were to: (1) characterize Pcell electrophysiology, Ca(2+) cycling, and their rate dependence; (2) investigate mechanisms underlying Pcell arrhythmogenicity; and compare Pcell and Vcell ele  ...[more]

Similar Datasets

| S-EPMC1851913 | biostudies-literature
| S-EPMC4593979 | biostudies-literature
| S-EPMC2660221 | biostudies-literature
| S-EPMC3186923 | biostudies-literature
| S-EPMC3018669 | biostudies-literature
| S-EPMC8671274 | biostudies-literature
| S-EPMC2877363 | biostudies-other
| S-EPMC3075371 | biostudies-literature
| S-EPMC2883657 | biostudies-literature
| S-EPMC8398821 | biostudies-literature