Dataset Information

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca²⁺current.

ABSTRACT:

Background

The study aimed to identify transcripts of specific ion channels in rat ventricular cardiomyocytes and determine their potential role in the regulation of ionic currents in response to mechanical stimulation. The gene expression levels of various ion channels in freshly isolated rat ventricular cardiomyocytes were investigated using the RNA-seq technique. We also measured changes in current through Ca_V1.2 channels under cell stretching using the whole-cell patch-clamp method.

Results

Among channels that showed mechanosensitivity, significant amounts of TRPM7, TRPC1, and TRPM4 transcripts were found. We suppose that the recorded L-type Ca²⁺ current is probably expressed through Ca_V1.2. Furthermore, stretching cells by 6, 8, and 10 μm, which increases I_SAC through the TRPM7, TRPC1, and TRPM4 channels, also decreased I_Ca,L through the Ca_V1.2 channels in K⁺ _in/K⁺ _out, Cs⁺ _in/K⁺ _out, K⁺ _in/Cs⁺ _out, and Cs⁺ _in/Cs⁺ _out solutions. The application of a nonspecific I_SAC blocker, Gd³⁺, during cell stretching eliminated I_SAC through nonselective cation channels and I_Ca,L through Ca_V1.2 channels. Since the response to Gd³⁺ was maintained in Cs⁺ _in/Cs⁺ _out solutions, we suggest that voltage-gated Ca_V1.2 channels in the ventricular myocytes of adult rats also exhibit mechanosensitive properties.

Conclusions

Our findings suggest that TRPM7, TRPC1, and TRPM4 channels represent stretch-activated nonselective cation channels in rat ventricular myocytes. Probably the Ca_V1.2 channels in these cells exhibit mechanosensitive properties. Our results provide insight into the molecular mechanisms underlying stretch-induced responses in rat ventricular myocytes, which may have implications for understanding cardiac physiology and pathophysiology.

SUBMITTER: Kamkin AG

PROVIDER: S-EPMC10614344 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature

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Publications

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca<sup>2+</sup>current.

Kamkin Andre G AG Kamkina Olga V OV Kazansky Viktor E VE Mitrokhin Vadim M VM Bilichenko Andrey A Nasedkina Elizaveta A EA Shileiko Stanislav A SA Rodina Anastasia S AS Zolotareva Alexandra D AD Zolotarev Valentin I VI Sutyagin Pavel V PV Mladenov Mitko I MI

Biology direct 20231030 1

<h4>Background</h4>The study aimed to identify transcripts of specific ion channels in rat ventricular cardiomyocytes and determine their potential role in the regulation of ionic currents in response to mechanical stimulation. The gene expression levels of various ion channels in freshly isolated rat ventricular cardiomyocytes were investigated using the RNA-seq technique. We also measured changes in current through Ca<sub>V</sub>1.2 channels under cell stretching using the whole-cell patch-cla ...[more]

PMID: 37899484

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Project description:At the cellular level, cardiac alternans is observed as beat-to-beat alternations in contraction strength, action potential (AP) morphology and Ca2+ transient (CaT) amplitude, and is a risk factor for cardiac arrhythmia. The (patho)physiological roles of small conductance Ca2+ -activated K+ (SK) channels in ventricles are poorly understood. We tested the hypothesis that in single rabbit ventricular myocytes pharmacological modulation of SK channels plays a causative role for the development of pacing-induced CaT and AP duration (APD) alternans. SK channel blockers (apamin, UCL1684) had only a minor effect on AP repolarization. However, SK channel activation by NS309 resulted in significant APD shortening, demonstrating that functional SK channels are well expressed in ventricular myocytes. The effects of NS309 were prevented or reversed by apamin and UCL1684, indicating that NS309 acted on SK channels. SK channel activation abolished or reduced the degree of pacing-induced CaT and APD alternans. Inhibition of KV 7.1 (with HMR1556) and KV 11.1 (with E4031) channels was used to mimic conditions of long QT syndromes type-1 and type-2, respectively. Both HMR1556 and E4031 enhanced CaT alternans that was prevented by SK channel activation. In AP voltage-clamped cells the SK channel activator had no effect on CaT alternans, confirming that suppression of CaT alternans was caused by APD shortening. APD shortening contributed to protection from alternans by lowering sarcoplasmic reticulum Ca2+ content and curtailing Ca2+ release. The data suggest that SK activation could be a potential intervention to avert development of alternans with important ramifications for arrhythmia prevention and therapy for patients with long QT syndrome. KEY POINTS: At the cellular level, cardiac alternans is observed as beat-to-beat alternations in contraction strength, action potential (AP) morphology and intracellular Ca2+ release amplitude, and is a risk factor for cardiac arrhythmia. The (patho)physiological roles of small conductance Ca2+ -activated K+ (SK) channels in ventricles are poorly understood. We investigated whether pharmacological modulation of SK channels affects the development of cardiac alternans in normal ventricular cells and in cells with drug-induced long QT syndrome (LQTS). While SK channel blockers have only a minor effect on AP morphology, their activation leads to AP shortening and abolishes or reduces the degree of pacing-induced Ca2+ and AP alternans. AP shortening contributed to protection against alternans by lowering sarcoplasmic reticulum Ca2+ content and curtailing Ca2+ release. The data suggest SK activation as a potential intervention to avert the development of alternans with important ramifications for arrhythmia prevention for patients with LQTS.

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Dataset Information

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca²⁺current.

Background

Results

Conclusions

Publications

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca<sup>2+</sup>current.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca2+current.

Background

Results

Conclusions

Publications

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca<sup>2+</sup>current.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca²⁺current.