In permeabilized rat ventricular myocytes, Ca2+ wave propagation is highly dependent on EGTA concentration, while Ca2+ spark frequency is modulated by Ca2+, calmodulin, and cADPR.
Answers are grounded in this paper and cite their sources.
Does not alter clinical Ca2+ handling strategies; leaves open whether calmodulin or cADPR regulate waves in intact myocardium.
We carried out confocal Ca2+ imaging in myocytes permeabilized with saponin in 'internal' solutions containing: MgATP, EGTA and fluo-3 potassium salt. 2. Permeabilized myocytes exhibited spontaneous Ca2+ sparks and waves similar to those observed in intact myocytes loaded with fluo-3 AM. 3. In the presence of 'low' [EGTA] (0.05 mM), Ca2+ waves arose regularly, even at relatively low [Ca2+] (50-100 nM, free). Increasing [EGTA] resulted in decreased frequency and propagation velocity of Ca2+ waves. Propagating waves were completely abolished at [EGTA] > 0.3 mM. 4. The frequency of sparks increased as a function of [Ca2+] (50-400 nM range) with no sign of a high affinity Ca2+-dependent inactivation process. 5. The rate of occurrence of Ca2+ sparks was increased by calmodulin and cyclic adenosine diphosphate-ribose (cADPR).
No takes yet. Share an insight, caveat, or question.
Lukyanenko et al. (1999) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: