Increase of empty pool-activated Ca2+ influx using an intracellular Ca2+ chelating agent

Area of Science:

• Cellular physiology
• Vascular biology
• Calcium signaling

Background:

• Intracellular calcium (Ca2+) regulates vascular smooth muscle cell function.
• Understanding Ca2+ influx mechanisms is crucial for cardiovascular research.

Purpose of the Study:

• To investigate the effect of BAPTA preloading on stimulated Ca2+ influx in vascular smooth muscle cells.
• To explore the mechanisms underlying altered Ca2+ dynamics.

Main Methods:

• A7r5 vascular smooth muscle cells were preloaded with BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid).
• Stimulated 45Ca2+ influx was induced by [Arg]8 vasopressin or thapsigargin.
• Changes in Ca2+ influx were quantified.

Main Results:

• BAPTA preloading increased stimulated 45Ca2+ influx more than threefold.
• This increase may result from attenuated Ca2+ feedback inhibition and enhanced cellular Ca2+ buffering.
• Diminished cellular Ca2+ release was also observed.

Conclusions:

• BAPTA preloading significantly enhances stimulated Ca2+ influx in vascular smooth muscle cells.
• This technique offers a novel approach to study receptor-induced Ca2+ entry.
• Findings provide insights into calcium regulation in vascular tissues.