HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 290/6/H2295    most recent 00260.2005v1 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 Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Gashev, A. A. Articles by Zawieja, D. C. Search for Related Content PubMed PubMed Citation Articles by Gashev, A. A. Articles by Zawieja, D. C.

Inhibition of active lymph pump by simulated microgravity in rats

¹Department of Medical Physiology, College of Medicine, Cardiovascular Research Institute Division of Lymphatic Biology, Texas A&M University System Health Science Center and ²Department of Health and Kinesiology, Texas A&M University, College Station, Texas

Submitted 17 March 2005 ; accepted in final form 3 January 2006

During spaceflight the normal head-to-foot hydrostatic pressure gradients are eliminated and body fluids shift toward the head, resulting in a diminished fluid volume in the legs and an increased fluid volume in the head, neck, and upper extremities. Lymphatic function is important in the maintenance of normal tissue fluid volume, but it is not clear how microgravity influences lymphatic pumping. We performed a detailed evaluation of the influence of simulated microgravity on lymphatic diameter, wall thickness, elastance, tone, and other measures of phasic contractility in isolated lymphatics. Head-down tail suspension (HDT) rats were used to simulate the effects of microgravity. Animals were exposed to HDT for 2 wk, after which data were collected and compared with the control non-HDT group. Lymphatics from four regional lymphatic beds (thoracic duct, cervical, mesenteric, and femoral lymphatics) were isolated, cannulated, and pressurized. Input and output pressures were adjusted to apply a range of transmural pressures and flows to the lymphatics. Simulated microgravity caused a potent inhibition of pressure/stretch-stimulated pumping in all four groups of lymphatics. The greatest inhibition was found in cervical lymphatics. These findings presumably are correlated to the cephalic fluid shifts that occur in HDT rats as well as those observed during spaceflight. Flow-dependent pump inhibition was increased after HDT, especially in the thoracic duct. Mesenteric lymphatics were less strongly influenced by HDT, which may support the idea that lymph hydrodynamic conditions in the mesenteric lymphatic during HDT are not dramatically altered.

lymphatic vessels; thoracic duct; lymphatics

This article has been cited by other articles:

				S. Suzuki, R. Mizuno, F. Ikomi, and T. Ohhashi Head-down tilt posture elicits transient lymphocyte mobilization from the iliac, but not mesenteric, lymph nodes of rats J Appl Physiol, November 1, 2008; 105(5): 1595 - 1601. [Abstract] [Full Text] [PDF]

				B. J. Behnke, D. C. Zawieja, A. A. Gashev, C. A. Ray, and M. D. Delp Diminished mesenteric vaso- and venoconstriction and elevated plasma ANP and BNP with simulated microgravity J Appl Physiol, May 1, 2008; 104(5): 1273 - 1280. [Abstract] [Full Text] [PDF]

				K. A. Radek, L. A. Baer, J. Eckhardt, L. A. DiPietro, and C. E. Wade Mechanical unloading impairs keratinocyte migration and angiogenesis during cutaneous wound healing J Appl Physiol, May 1, 2008; 104(5): 1295 - 1303. [Abstract] [Full Text] [PDF]

				M. D. Delp Unraveling the complex web of impaired wound healing with mechanical unloading and physical deconditioning J Appl Physiol, May 1, 2008; 104(5): 1262 - 1263. [Full Text] [PDF]