Abstract
BayK 8644, an L-type Ca2+ channel agonist, has been shown to increase sarcoplasmic reticulum (SR) Ca2+ release in dog and ferret ventricular muscle. The visualization of local increase in cytosolic Ca2+ concentration, called the 'Ca2+ spark', has enabled us to investigate the elementary events of the BayK-induced Ca2+ release from the SR. In this study, the effects of BayK on twitch Ca2+ transients and Ca2+ sparks were examined in ferret ventricular myocytes with laser scanning confocal microscopy and a fluorescent calcium indicator, fluo 3. BayK converted the post rest potentiation of twitch Ca2+ transients to decay. The Ca2+ spark frequency under control conditions was fairly constant during 20 s of rest after interruption of electrical stimulation. BayK (100 nM) increased the spark frequency by 465.7 ± 90.3% of control but did not change the spatial and temporal characteristics of the individual sparks. The increase in spark frequency by BayK was not affected by perfusion with Ca2+-free solution, but was suppressed by the addition of nifedipine (10 μM), suggesting that the BayK effects on Ca2+ sparks were mediated by the sarcolemmal dihydropyridine (DHP) receptor, but were independent of Ca2+ influx. These findings suggest that BayK activates SR Ca2+ release at rest through a putative linkage between the sarcolemmal DHP receptor and the SR ryanodine receptor.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 58-61 |
| Number of pages | 4 |
| Journal | Heart and Vessels |
| Volume | 12 |
| Issue number | SUPPL. 12 |
| State | Published - 1997 |
| Externally published | Yes |
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Keywords
- BayK 8644
- Calcium spark
- Confocal microscopy
- Fluo 3
- Sarcoplasmic reticulum
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
Cite this
BayK 8644 increases resting calcium spark frequency in ferret ventricular myocytes. / Satoh, Hiroshi; Hayashi, Hideharu; Blatter, Lothar A.; Bers, Donald M.
In: Heart and Vessels, Vol. 12, No. SUPPL. 12, 1997, p. 58-61.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - BayK 8644 increases resting calcium spark frequency in ferret ventricular myocytes
AU - Satoh, Hiroshi
AU - Hayashi, Hideharu
AU - Blatter, Lothar A.
AU - Bers, Donald M
PY - 1997
Y1 - 1997
N2 - BayK 8644, an L-type Ca2+ channel agonist, has been shown to increase sarcoplasmic reticulum (SR) Ca2+ release in dog and ferret ventricular muscle. The visualization of local increase in cytosolic Ca2+ concentration, called the 'Ca2+ spark', has enabled us to investigate the elementary events of the BayK-induced Ca2+ release from the SR. In this study, the effects of BayK on twitch Ca2+ transients and Ca2+ sparks were examined in ferret ventricular myocytes with laser scanning confocal microscopy and a fluorescent calcium indicator, fluo 3. BayK converted the post rest potentiation of twitch Ca2+ transients to decay. The Ca2+ spark frequency under control conditions was fairly constant during 20 s of rest after interruption of electrical stimulation. BayK (100 nM) increased the spark frequency by 465.7 ± 90.3% of control but did not change the spatial and temporal characteristics of the individual sparks. The increase in spark frequency by BayK was not affected by perfusion with Ca2+-free solution, but was suppressed by the addition of nifedipine (10 μM), suggesting that the BayK effects on Ca2+ sparks were mediated by the sarcolemmal dihydropyridine (DHP) receptor, but were independent of Ca2+ influx. These findings suggest that BayK activates SR Ca2+ release at rest through a putative linkage between the sarcolemmal DHP receptor and the SR ryanodine receptor.
AB - BayK 8644, an L-type Ca2+ channel agonist, has been shown to increase sarcoplasmic reticulum (SR) Ca2+ release in dog and ferret ventricular muscle. The visualization of local increase in cytosolic Ca2+ concentration, called the 'Ca2+ spark', has enabled us to investigate the elementary events of the BayK-induced Ca2+ release from the SR. In this study, the effects of BayK on twitch Ca2+ transients and Ca2+ sparks were examined in ferret ventricular myocytes with laser scanning confocal microscopy and a fluorescent calcium indicator, fluo 3. BayK converted the post rest potentiation of twitch Ca2+ transients to decay. The Ca2+ spark frequency under control conditions was fairly constant during 20 s of rest after interruption of electrical stimulation. BayK (100 nM) increased the spark frequency by 465.7 ± 90.3% of control but did not change the spatial and temporal characteristics of the individual sparks. The increase in spark frequency by BayK was not affected by perfusion with Ca2+-free solution, but was suppressed by the addition of nifedipine (10 μM), suggesting that the BayK effects on Ca2+ sparks were mediated by the sarcolemmal dihydropyridine (DHP) receptor, but were independent of Ca2+ influx. These findings suggest that BayK activates SR Ca2+ release at rest through a putative linkage between the sarcolemmal DHP receptor and the SR ryanodine receptor.
KW - BayK 8644
KW - Calcium spark
KW - Confocal microscopy
KW - Fluo 3
KW - Sarcoplasmic reticulum
UR - http://www.scopus.com/inward/record.url?scp=0031283326&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031283326&partnerID=8YFLogxK
M3 - Article
C2 - 9476545
AN - SCOPUS:0031283326
VL - 12
SP - 58
EP - 61
JO - Heart and Vessels
JF - Heart and Vessels
SN - 0910-8327
IS - SUPPL. 12
ER -