Descending Vasa Recta Endothelial Membrane Potential Response Requires Pericyte Communication.

Area of Science:

• Physiology
• Vascular Biology
• Cellular Electrophysiology

Background:

• The descending vasa recta (DVR) wall comprises pericytes and endothelial cells.
• Understanding cell-to-cell communication within the DVR wall is crucial for regulating renal blood flow.

Purpose of the Study:

• To investigate the mechanisms of membrane potential equilibration between pericytes and endothelial cells in the DVR.
• To determine the role of direct cell-to-cell contact versus endothelial signaling in regulating DVR pericyte electrophysiology.

Main Methods:

• Dual-cell electrophysiological recording was used to measure membrane potentials.
• Experiments involved intact DVR vessels, isolated pericytes, and co-cultured pericyte-endothelial cells.
• Vasoconstrictor agonists (angiotensin II, vasopressin, endothelin 1) were applied to stimulate cells.

Main Results:

• Pericytes exhibited closely equilibrated membrane potentials and coordinated responses to vasoconstrictors, even when physically separated from the endothelium but retaining contact with each other.
• Isolated pericytes (both from endothelium and each other) showed independent responses.
• Co-cultured pericytes and endothelial cells displayed similar resting potentials and coordinated responses; however, isolating pericytes from the endothelium led to discordant potentials.
• Complete endothelial isolation abolished angiotensin II-induced membrane potential responses.

Conclusions:

• Cell-to-cell transmission through the endothelium is not required for pericytes to equilibrate their membrane potentials.
• Angiotensin II-dependent responses in DVR endothelia may arise from gap junction coupling with pericytes, rather than solely from endothelial receptor-dependent signaling.