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This Article Full Text Full Text (PDF) All Versions of this Article: 296/6/H2015    most recent 00418.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Dongaonkar, R. M. Articles by Quick, C. M. PubMed PubMed Citation Articles by Dongaonkar, R. M. Articles by Quick, C. M.

Venomotion modulates lymphatic pumping in the bat wing

¹Michael E. DeBakey Institute, Texas A&M University and ³Division of Lymphatic Biology, Cardiovascular Research Institute, Texas A&M Health, Science Center, College Station, Texas; and ²Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri

Submitted 12 April 2008 ; accepted in final form 24 March 2009

In skin, it is believed that lymph must be pumped by intrinsic contraction of lymphatic muscle, since investigators have not considered that cyclical dilation of venules could compress adjacent lymphatic microvessels. Because lymphatic vessels are sensitive to stretch, we hypothesized that venomotion not only can cause extrinsic pumping of lymph in nearby lymphatic vessels, but also can stimulate intrinsic contractions. Bat wing venules have pronounced venomotion and are in close proximity to lymphatic microvessels, and can be studied noninvasively without the confounding effects of anesthesia, surgical trauma, or contrast agents. Therefore, the interaction between venules and their paired lymphatic vessels in unanesthetized Pallid bats (n = 8) was evaluated by recording the diameters of both vessels. Four sets of observations suggested that lymphatic and venous contractions were partially coupled. First, venous dilation and contraction produced a significant change in lymphatic microvascular cross-sectional area. Second, lymphatic microvascular contractions were immediately preceded by a change in venular diameter. Third, venular and lymphatic vessel contraction frequencies were positively correlated (r = 0.75). Fourth, time delays between peak venular systole and onset of lymphatic microvascular contraction were negatively correlated with venomotion magnitude (r = –0.55) and velocity (r = –0.64). In a separate experiment, inhibiting venomotion resulted in a 54.3 ± 20.0% (n = 8) decrease in lymphatic contraction frequency. Furthermore, 85.7% (n = 56) of lymphatic vessels switch sides and lie adjacent to arterioles when venules were too small to exhibit venomotion. These results are consistent with both extrinsic pumping of lymph and stretch-induced lymphatic contraction and imply that intrinsic and extrinsic pumping can be coupled.

lymphangion; edema; interstitial fluid balance; venular-lymphatic coupling