cADP ribose and [Ca2+](i) regulation in rat cardiac myocytes

Y.s. Prakash, Mathur S. Kannan, Timothy F. Walseth, Gary C Sieck

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

cADP ribose (cADPR)-induced intracellular Ca2+ concentration ([Ca2+](i)) responses were assessed in acutely dissociated adult rat ventricular myocytes using real-time confocal microscopy. In quiescent single myocytes, injection of cADPR (0.1-10 μM) induced sustained, concentration-dependent [Ca2+](i) responses ranging from 50 to 500 nM, which were completely inhibited by 20 μM 8-amino-cADPR, a specific blocker of the cADPR receptor. In myocytes displaying spontaneous [Ca2+](i) waves, increasing concentrations of cADPR increased wave frequency up to ~ 31250% of control. In electrically paced myocytes (0.5 Hz, 5-ms duration), cADPR increased the amplitude of [Ca2+](i) transients in a concentration-dependent fashion, up to 150% of control. Administration of 8-amino-cADPR inhibited both spontaneous waves as well as [Ca2+](i) responses to electrical stimulation, even in the absence of exogenous cADPR. However, subsequent [Ca2+](i) responses to 5 mM caffeine were only partially inhibited by 8-amino-cADPR. In contrast, even under conditions where ryanodine receptor (RyR) channels were blocked with ryanodine, high cADPR concentrations still induced an [Ca2+](i) response. These results indicate that in cardiac myocytes, cADPR induces Ca2+ release from the sarcoplasmic reticulum through both RyR channels and via mechanisms independent of RyR channels.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume279
Issue number4 48-4
StatePublished - 2000

Fingerprint

Cyclic ADP-Ribose
Cardiac Myocytes
Muscle Cells
Ryanodine Receptor Calcium Release Channel
Ryanodine
Sarcoplasmic Reticulum
Caffeine
Confocal Microscopy
Electric Stimulation

Keywords

  • Confocal microscopy
  • Heart
  • Intracellular calcium concentration
  • Ryanodine receptor
  • Sarcoplasmic reticulum
  • Second messenger

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

cADP ribose and [Ca2+](i) regulation in rat cardiac myocytes. / Prakash, Y.s.; Kannan, Mathur S.; Walseth, Timothy F.; Sieck, Gary C.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 279, No. 4 48-4, 2000.

Research output: Contribution to journalArticle

Prakash, Y.s. ; Kannan, Mathur S. ; Walseth, Timothy F. ; Sieck, Gary C. / cADP ribose and [Ca2+](i) regulation in rat cardiac myocytes. In: American Journal of Physiology - Heart and Circulatory Physiology. 2000 ; Vol. 279, No. 4 48-4.
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