Heterogeneous cytoplasmic calcium response in microvascular endothelial cells.

Area of Science:

• Endothelial cell biology
• Calcium signaling
• Vascular physiology

Background:

• Endothelial cells play a crucial role in vascular function.
• Calcium (Ca2+) signaling is fundamental to cellular processes.
• Heterogeneity in cellular responses can impact tissue-level function.

Purpose of the Study:

• To investigate calcium concentration changes in response to ATP and shear stress in rat adrenomedullary endothelial cells (RAMECs).
• To elucidate the mechanisms underlying heterogeneous calcium responses and wave propagation.

Main Methods:

• Cultured rat adrenomedullary endothelial cells (RAMECs) were used.
• Changes in intracellular calcium concentration ([Ca2+]i) were monitored.
• Responses to exogenous ATP and induced shear stress were analyzed.
• The effect of suramin, a purinergic receptor blocker, was assessed.

Main Results:

• A significant heterogeneity in spatial and temporal calcium responses was observed.
• Shear stress and exogenous ATP induced calcium waves propagating between cells.
• Wave propagation was dependent on ATP concentration and suppressed by suramin.
• Heterogeneous purinergic receptor distribution was identified as a key factor in response variability.

Conclusions:

• ATP acts as an autocrine and paracrine mediator in RAMECs.
• Purinergic receptors mediate calcium wave propagation initiated by ATP or shear stress.
• Heterogeneous purinergic receptor distribution contributes to coordinated vascular function through integrated cellular responses.