Contribution of red cell aggregation to venous vascular resistance
in skeletal muscle.
Cabel, Milos, Herbert J. Meiselman, Aleksander S. Popel, and Paul C.
Johnson.
Dept. of Physiology, University of Arizona College of Medicine,
Tucson AZ, 85724; Dept. of Physiology and Biophysics, University of
Southern California School of Medicine, Los Angeles CA, 90033; and
Dept. of Biomedical Engineering, Johns Hopkins University School of
Medicine, Baltimore MD, 21205
APStracts 3:0323H, 1996.
The effects of red cell aggregation on venous vascular resistance and
conductance were examined in the cat lateral gastrocnemius muscle.
During perfusion with blood of normal hematocrit venous conductance
fell linearly by 41% when blood flow was reduced from 5 ml/min x 100g
tissue to 1 ml/min x 100g tissue and increased linearly by 155% when
flow was increased from 5 to 20 ml/min x 100g tissue. This effect was
not seen when the muscle was perfused with an acellular solution of
12% Dextran 40 in Ringers solution and greatly reduced or absent with
a non-aggregating suspension of red cells in Ringers solution plus
Dextran 40. Also, the venous vascular conductance at a control flow
of 5 ml/min x 100g tissue during perfusion with the non-aggregating
red cell suspension was twice that seen with normal blood of the same
hematocrit. The effect of flow on venous conductance was
significantly reduced when red cell aggregation was increased by
adding Dextran 250 to the blood (200 mg/kg body weight) and was also
reduced in animals with systemic hematocrit above 50%. These findings
suggest that red cell aggregation contributes importantly to venous
vascular resistance in resting muscle.
Received 28 November 1995; accepted in final form 17 July 1996.
APS Manuscript Number H1106-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 August 1996