Abstract
The pulmonary vein is surrounded by an external sleeve of cardiomyocytes that are widely recognised
to play an important role in atrial fibrillation. While intracellular Ca2+ is thought to influence the electrical
activity of cardiomyocytes, there have been relatively few studies examining Ca2+ signalling in these
cells. Therefore, using fluo-4 and fluorescence imaging microscopy, we have investigated Ca2+ signalling
in an intact section of the rat pulmonary vein. Under resting conditions cardiomyocytes displayed spontaneous
Ca2+ transients, which were variable in amplitude and had a frequency of 1.6±0.03 Hz. The Ca2+
transients were asynchronous amongst neighbouring cardiomyocytes and tended to propagate throughout
the cell as a wave. Removing extracellular Ca2+ produced a slight reduction in the amplitude and
frequency of the spontaneous Ca2+ transients; however, ryanodine (20M) had a much greater effect on
the amplitude and reduced the frequency by 94±2%. Blocking IP3 receptors with 2-aminoethoxydiphenyl
borate (20M) also reduced the amplitude and frequency (by 73±11%) of these events, indicating the
importance of Ca2+ release from the SR. Electrical field stimulation of the pulmonary vein produced
Ca2+ transients in cardiomyocytes that were significantly reduced by either voltage-gated Ca2+ channel
blockers or ryanodine.
Original language | English |
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Pages (from-to) | 150-160 |
Number of pages | 11 |
Journal | Cell Calcium |
Volume | 48 |
Issue number | 2-3 |
DOIs | |
Publication status | Published - Aug 2010 |
Keywords
- cardiomyocytes
- pulmonary vein
- pharmacology
- cell calcium