AJP - Heart and Circulatory Physiology, Vol 243, Issue 4 575-H583, Copyright © 1982 by American Physiological Society
Effect of norepinephrine on lymph flow and edema formation in the canine forelimb
J. T. O'Neill, F. J. Haddy and G. J. Grega
In the present study we sought evidence for the hypothesis that
norepinephrine (NE) can cause constriction of lymph vessels in the canine
forelimb perfused at constant flow. Mechanical venous compression
(small-vein pressure approximately equal to 45 mmHg), intra-arterial
infusion of histamine (16 micrograms base/min), and intra-arterial infusion
of NE (16 micrograms base/min) caused the limbs to gain weight at similar
rates due to edema formation; the first two maneuvers caused a sustained
increase in skin lymph flow, but the increase in lymph flow with NE was
only transient. Similar changes were seen during infusion of NE at 1 and 2
micrograms/min, and studies with radioactive microspheres indicated that NE
increased capillary blood flow. When venous pressure was elevated and held
constant at 45 mmHg. NE (4 micrograms base/min ia) antagonized and
phentolamine (400 micrograms/min ia) potentiated the increase in skin lymph
flow. Finally, NE (16 micrograms base/min ia) caused a reduction in
histamine (16 micrograms base/min)-elevated skin lymph flow, despite the
fact that capillary pressure was greatly increased due to active venous
constriction. We conclude that intra-arterial infusion of norepinephrine in
the dog forelimb perfused at constant flow causes constriction of lymphatic
trunk vessels in skin, resulting in increased resistance to the flow of
lymph.
