Calcium signaling in endocardial and epicardial ventricular myocytes from streptozotocin-induced diabetic rats

Lina T. Al Kury, Vadym Sydorenko, Manal M.A. Smail, Muhammad A. Qureshi, Anatoly Shmygol, Dimitrios Papandreou, Jaipaul Singh, Frank Christopher Howarth

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Aims/Introduction: Abnormalities in Ca2+ signaling have a key role in hemodynamic dysfunction in diabetic heart. The purpose of this study was to explore the effects of streptozotocin (STZ)-induced diabetes on Ca2+ signaling in epicardial (EPI) and endocardial (ENDO) cells of the left ventricle after 5–6 months of STZ injection. Materials and Methods: Whole-cell patch clamp was used to measure the L-type Ca2+ channel (LTCC) and Na+/Ca2+ exchanger currents. Fluorescence photometry techniques were used to measure intracellular free Ca2+ concentration. Results: Although the LTCC current was not significantly altered, the amplitude of Ca2+ transients increased significantly in EPI-STZ and ENDO-STZ compared with controls. Time to peak LTCC current, time to peak Ca2+ transient, time to half decay of LTCC current and time to half decay of Ca2+ transients were not significantly changed in EPI-STZ and ENDO-STZ myocytes compared with controls. The Na+/Ca2+ exchanger current was significantly smaller in EPI-STZ and in ENDO-STZ compared with controls. Conclusions: STZ-induced diabetes resulted in an increase in amplitude of Ca2+ transients in EPI and ENDO myocytes that was independent of the LTCC current. Such an effect can be attributed, at least in part, to the dysfunction of the Na+/Ca2+ exchanger. Additional studies are warranted to improve our understanding of the regional impact of diabetes on Ca2+ signaling, which will facilitate the discovery of new targeted treatments for diabetic cardiomyopathy.

Original languageEnglish
Pages (from-to)493-500
Number of pages8
JournalJournal of Diabetes Investigation
Issue number4
Publication statusPublished - Apr 2021


  • Ca transients
  • Na/Ca exchanger
  • Streptozotocin-induced diabetes

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism


Dive into the research topics of 'Calcium signaling in endocardial and epicardial ventricular myocytes from streptozotocin-induced diabetic rats'. Together they form a unique fingerprint.

Cite this