Modelling pacemaker oscillations in lymphatic muscle cells: lengthened action potentials by two distinct system...

Area of Science:

• Physiology
• Biophysics
• Cardiovascular Science

Background:

• Lymphatic system failures are linked to cardiovascular and other diseases.
• Lymphatic muscle cells (LMCs) drive fluid pumping via periodic contractions.
• These contractions involve coupled oscillations in membrane potential (M-clock) and calcium (C-clock).

Purpose of the Study:

• To modify a previous minimal model of LMC oscillations.
• To accurately replicate the action potential shape, including systolic plateau variations.
• To investigate dynamical mechanisms underlying plateau formation.

Main Methods:

• Phase-plane analysis of a modified dual-clock model.
• Incorporation of a ryanodine receptor into the model.
• Comparison of model predictions with experimental data.

Main Results:

• Identified two distinct dynamical mechanisms for plateau formation: M-clock-driven and C-clock-driven.
• The C-clock-driven mechanism involves a ryanodine receptor.
• The improved model shows enhanced fidelity to experimental data, particularly for calcium levels.

Conclusions:

• The refined model accurately captures LMC action potential plateau behavior.
• Understanding these dynamical mechanisms is key to lymphatic system function.
• This enhanced model can guide pharmacological interventions for lymphatic pumping defects.