Intercellular ultrafast Ca(2+) wave in vascular smooth muscle cells: numerical and experimental study

Area of Science:

• Physiology
• Cell Biology
• Biophysics

Background:

• Vascular smooth muscle cells (VSMCs) exhibit intercellular calcium (Ca2+) waves.
• A novel ultrafast Ca2+ wave in VSMCs was recently observed in vitro.
• This wave was hypothesized to involve membrane potential and Ca2+ dynamics.

Purpose of the Study:

• To experimentally measure membrane depolarization velocity in VSMCs.
• To simulate ultrafast Ca2+ waves along coupled VSMCs.
• To investigate the role of membrane depolarization in mediating these waves.

Main Methods:

• Experimental measurement of membrane depolarization conduction velocity.
• Computational simulations of coupled VSMC networks.
• Analysis of Ca2+ wave dynamics and dependence on various parameters.

Main Results:

• Numerical simulations accurately reproduced experimental observations of Ca2+ wave velocity.
• Electrotonic membrane depolarization was observed along the cell network.
• Wave speed was independent of intracellular Ca2+ stores and sensitive to specific model parameters.

Conclusions:

• Experimental and numerical data support membrane depolarization as an intercellular messenger for ultrafast Ca2+ waves in VSMCs.
• The study provides insights into model parameters that can experimentally modulate wave characteristics.
• This mechanism highlights a novel signaling pathway in vascular smooth muscle function.