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This Article Full Text Full Text (PDF) All Versions of this Article: 296/2/H293    most recent 01040.2008v1 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 Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Davis, M. J. Articles by Gashev, A. A. Search for Related Content PubMed PubMed Citation Articles by Davis, M. J. Articles by Gashev, A. A.

Myogenic constriction and dilation of isolated lymphatic vessels

¹Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri; and ²Division of Lymphatic Biology, Department of Systems Biology and Translational Medicine, Cardiovascular Research Institute, Texas A & M Health Science Center, Temple, Texas

Submitted 29 September 2008 ; accepted in final form 19 November 2008

We tested the hypothesis that lymphatics would exhibit myogenic constrictions and dilations to intraluminal pressure changes. Collecting lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized for in vitro study. The lymphatic diameter responses to controlled intraluminal pressure steps of different magnitudes were tested in the absence and presence of the inflammatory mediator substance P, which is known to enhance lymphatic contractility. Myogenic constriction, defined as a time-dependent decrease in end-diastolic diameter over a 1- to 2-min period following pressure elevation (after initial distension), was observed in the majority of rat mesenteric lymphatic vessels in vitro and occurred over a relatively wide pressure range (1–15 cmH₂O). Myogenic dilation, a time-dependent rise in end-diastolic diameter following pressure reduction, was observed in over half the vessels equilibrated at a low baseline pressure. Myogenic constrictions were independent of the cardiac-like and time-dependent compensatory decline in end-systolic diameter and increase in amplitude observed in almost all vessels following pressure elevation. Substance P increased the percentage of vessels exhibiting myogenic constriction, the magnitude and rate of constriction, and the pressure range over which constriction occurred. Our results demonstrate that myogenic responses occur in collecting lymphatic vessels and suggest that the response may aid in preventing vessel overdistension during inflammation/edema.

lymphatic contraction; lymphatic contractility; substance P; inflammation