Action potentials and potassium currents in rat ventricular muscle during experimental diabetes

Magyar, János; Rusznák, Zoltán; Szentesi, Péter; Szücs, G; Kovács, László

doi:10.1016/0022-2828(92)91098-p

Cited by 117 publications

(104 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In RV, I K was reduced 10 %, in EpiALV 32 % and in EndoBLV 48 %. As previously reported, I K1 was not affected by diabetes [9,13]. From these results we suggest that the re- gional differences in APD lengthening induced by experimental diabetes are explained by the uneven decrease in I K and the differences in the relative contribution of the depolarisation-activated outward currents to the repolarisation process.…”

Section: Discussionsupporting

confidence: 84%

“…Type I diabetes increased APD measured at 90 % of repolarisation 80 %, 125 % and 148 %, respectively. Previous studies have also found increases in APD; no comparisons were, however, made between the different regions of the ventricle [9,13]. These results suggest that the epicardial-endocardial differences in APD are increased in Type I diabetic rats.…”

Section: Discussioncontrasting

confidence: 66%

“…None took into account, however, the regional variability in the duration of the action potential under control conditions [10,11]. Various reports pointed to a lowering of the transient outward current, I to [9,12,13] and, to a lesser extent, the delayed rectifying outward current, I K [9,12], as the main cause of the lengthening of APD. Initial studies did not take into account regional variations in the distribution of the repolarising outward Diabetologia (2000) Abstract Aims/hypothesis.…”

mentioning

confidence: 99%

“…Effects of diabetic cardiomyopathy on regional electrophysiologic characteristics of rat ventricle potassium currents [9,12,13]. A more recent study only used animals with diabetes of short duration, 6 to 7 days after streptozotocin treatment [14].…”

mentioning

confidence: 99%

“…The effect of diabetes induced by streptozotozin on action potential waveform reaches its maximum by 4 weeks [13]. In the lifespan of a rat this can be considered as longterm diabetes.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Effects of diabetic cardiomyopathy on regional electrophysiologic characteristics of rat ventricle

Casis

Gallego

Iriarte³

et al. 2000

Diabetologia

View full text Add to dashboard Cite

The electrocardiogram of diabetic patients shows a series of deviations from normal patterns, most of which involve the QT interval and the T wave. The QT interval is longer in patients with diabetes mellitus than in normal people [1]. Diabetic patients show a corrected QT interval (QTc), measured using Bazett's formula, longer than 0.44 s [2,3]. Using Holter ECG monitoring, the appearance of ventricular late potentials is more frequent in patients with Type I (insulin-dependent) diabetes mellitus than in healthy people, and even more frequent in patients with Type II (non-insulin-dependent) diabetes mellitus [4,5]. Nearly all these changes are related to repolarisation. The QRS complex lasts longer in diabetic patients than in control subjects, suggesting intracardiac conduction disorders, but this type of change has only been described in children [6].Various studies report a lengthening of the duration of the rat ventricular action potential (APD) stemming from diabetic cardiomyopathy as a possible cause of these changes [7±9]. None took into account, however, the regional variability in the duration of the action potential under control conditions [10,11]. Various reports pointed to a lowering of the transient outward current, I to [9,12,13] and, to a lesser extent, the delayed rectifying outward current, I K [9,12], as the main cause of the lengthening of APD. Initial studies did not take into account regional variations in the distribution of the repolarising outward Diabetologia (2000) Abstract Aims/hypothesis. To identify the possible causes of the lengthening of the action potential duration described in patients affected by diabetes mellitus. Methods. We studied the effects of streptozotocininduced diabetes on the current density of the repolarising potassium currents I to , I K , I ss and I K1 in enzymatically isolated myocytes from three different regions of rat heart: total right ventricle, subepicardium at the apex of the left ventricle and subendocardium at the base of the left ventricle. Results. No changes in I K1 were found due to diabetes, but there was a uniform decrease in I to (50 %) and I ss (40 %) current densities in the three regions.In contrast, I K diminished unevenly, with the greatest decrease in the subendocardium at the base of the left ventricle (48 %), followed by the subepicardium at the apex of the left ventricle (32 %) and right ventricle (10 %). Conclusion/interpretation. These findings suggest the existence of regional differences in ion channel expression associated with diabetes. The decrease of these repolarising currents could account for the lengthening of action potential and the consequent change in the Q-T interval of the ECG observed in diabetic rats. [Diabetologia (2000)

show abstract

Section: Discussionsupporting

confidence: 84%

Section: Discussioncontrasting

confidence: 66%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…The effect of diabetes induced by streptozotozin on action potential waveform reaches its maximum by 4 weeks [13]. In the lifespan of a rat this can be considered as longterm diabetes.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Effects of diabetic cardiomyopathy on regional electrophysiologic characteristics of rat ventricle

Casis

Gallego

Iriarte³

et al. 2000

Diabetologia

View full text Add to dashboard Cite

show abstract

Glucagon‐Like Peptide‐1 (GLP‐1) Rescue Diabetic Cardiac Dysfuntions in Human iPSC‐Derived Cardiomyocytes

Zhou

Huang

et al. 2022

Advanced Biology

View full text Add to dashboard Cite

Glucagon‐like peptide‐1 (GLP‐1) can improve cardiac function and cardiovascular outcomes in diabetic cardiomyopathy; however, the beneficial effect of GLP‐1 on human diabetic cardiomyocytes (DCMs) and its mechanism have not been fully elucidated. Here, the DCMs model by human‐induced pluripotent stem cells‐derived cardiomyocytes is developed. Two subtypes of GLP‐1, GLP‐17–36 and GLP‐19‐36, are evaluated for their efficacy on the DCMs model. Diabetogenic condition is sufficient to induce most characteristics of diabetic cardiomyopathy in vitro, such as cardiac hypertrophy, lipid accumulation, impaired calcium transients, and abnormal electrophysiological properties. GLP‐17−36 and GLP‐19–36 can restore cardiomyocyte hypertrophic phenotype, impaired calcium transient frequency, abnormal action potential amplitude, depolarization, and repolarization velocity. Interestingly, RNA‐seq reveals different pathways altered by GLP‐17–36 and GLP‐19–36, respectively. Differentially expressed gene analysis reveals that possible targets of GLP‐17–36 involve the regulation of mitotic nuclear division and extracellular matrix–receptor interaction, while possible targets of GLP‐19–36 involve kinetochore assembly, and the complement and coagulation cascades. This study demonstrates the therapeutic effects of GLP‐1 on human DCMs and provides a novel platform to unveil the cellular mechanisms of diabetic cardiomyopathy, shedding light on discovering better targets for novel therapeutic interventions.

show abstract

Modulation of Electrical Properties by Ions, Hormones, and Drugs

Hiraoka

2002

Comprehensive Physiology

View full text Add to dashboard Cite

Action potentials and potassium currents in rat ventricular muscle during experimental diabetes

Cited by 117 publications

References 30 publications

Effects of diabetic cardiomyopathy on regional electrophysiologic characteristics of rat ventricle

Effects of diabetic cardiomyopathy on regional electrophysiologic characteristics of rat ventricle

Glucagon‐Like Peptide‐1 (GLP‐1) Rescue Diabetic Cardiac Dysfuntions in Human iPSC‐Derived Cardiomyocytes

Modulation of Electrical Properties by Ions, Hormones, and Drugs

Contact Info

Product

Resources

About