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Updated: Jun 24, 2026
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Real-time Evaluation of Absolute, Cytosolic, Free Ca2+ and Corresponding Contractility in Isolated, Pressurized Lymph Vessels
Published on: March 22, 2024
Venomotion modulates lymphatic pumping in the bat wing
Ranjeet M Dongaonkar1, Randolph H Stewart, Glen A Laine
1Michael E. DeBakey Institute, TAMU 4466, Texas A&M University, College Station, TX 77843-4466, USA.
Summary
Venous pulsatility (venomotion) can extrinsically pump lymph and stimulate intrinsic lymphatic contractions. This study in bats reveals a coupled pumping mechanism between venules and lymphatic vessels, challenging previous assumptions about lymph transport.
Area of Science:
- Physiology
- Cardiovascular Biology
- Lymphatic System Dynamics
Background:
- Lymphatic fluid transport is traditionally attributed to intrinsic muscle contractions.
- The potential role of extrinsic forces, such as venular pulsatility, in lymph pumping has been largely overlooked.
- Lymphatic vessels are known to be sensitive to mechanical stretch.
Purpose of the Study:
- To investigate whether cyclical dilation and contraction of venules (venomotion) can influence lymphatic microvessel function.
- To test the hypothesis that venomotion can provide extrinsic pumping for lymph and stimulate intrinsic lymphatic contractions.
- To explore the interaction between venules and adjacent lymphatic vessels in unanesthetized bats.
Main Methods:
- Noninvasive recording of simultaneous venular and lymphatic microvessel diameters in unanesthetized Pallid bats.
- Analysis of the correlation between venular diameter changes and lymphatic microvessel contractions.
- Evaluation of lymphatic contraction frequency after inhibiting venomotion.
- Observation of lymphatic vessel proximity to arterioles when venules lack venomotion.
Main Results:
- Venous dilation and contraction significantly altered lymphatic microvascular cross-sectional area.
- Lymphatic microvascular contractions consistently followed changes in venular diameter.
- Positive correlation observed between venular and lymphatic vessel contraction frequencies (r=0.75).
- Inhibition of venomotion led to a significant decrease in lymphatic contraction frequency (54.3%).
- Lymphatic vessels were found adjacent to arterioles when venules were too small for venomotion.
Conclusions:
- Venomotion contributes to extrinsic lymphatic pumping and can induce stretch-mediated intrinsic lymphatic contractions.
- Lymphatic and venous pumping mechanisms are partially coupled, suggesting a coordinated fluid transport system.
- These findings challenge the exclusive reliance on intrinsic lymphatic muscle contraction for lymph transport.
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