Lymphatic pump function curves in awake sheep.
Drake, R. E., S. Dhother, V. M. Oppenlander, and J. C. Gabel.
Departments of Anesthesiology, The University of Texas-Houston
Medical School, Houston, Texas and The UCLA School of Medicine, Los
Angeles, California
APStracts 2:0277R, 1995.
We determined the relationship between flow rate and inflow pressure
for intestinal lymphatic vessels in 6 sheep. First we anesthetized
the sheep and cannulated both ends of a 6-10 cm long segment of
intestinal lymphatic. We allowed the sheep to recover from the
anesthesia for 2-24 hrs. To determine the flow rate-inflow pressure
relationship, we recorded the inflow pressure and infused Ringer's
solution into the lymphatic at rates from 34-510 [mu]l/min. The flow
rate-pressure relationship was not linear and it had two regions. For
flow rates less than _l50?[mu]l/min, inflow pressure < outflow
pressure. Thus the lymphatic pumped fluid against a pressure
gradient. For flow rates greater than 150[mu]l/min, inflow pressure
> outflow pressure and we attributed most of the flow to the
favorable inflow-outflow pressure gradient (passive flow). When we
used verapamil to inhibit lymphatic pumping, we found no flow for
inflow pressure < outflow pressure and flow increased linearly
for inflow pressure > outflow pressure. Our data for actively
pumping lymphatic vessels are consistent with the flow vs. pressure
relationships derived from mathematical models of the lymphatic pump.
Furthermore, our data with verapamil confirm that active lymphatic
pumping was responsible for the nonlinear flow vs. pressure
relationship for the lymphatic vessels.`
Received 9 December 1994; accepted in final form 23 August 1995.
APS Manuscript Number R697-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 14 November 95