Capillary diameter changes during low perfusion pressure and
reactive hyperemia in skeletal muscle of anesthetized rabbits.
Bosman, Jacqueline, Geert-Jan Tangelder, Mirjam G. A. Oude Egbrink,
Robert S. Reneman, and Dick W. Slaaf.
Departments of Biophysics and Physiology, Cardiovascular Research
Institute Maastricht, University of Limburg, P.O. Box 616, 6200 MD
Maastricht, The Netherlands
APStracts 2:0142H, 1995.
Capillary diameter changes were studied in the tenuissimus muscle of
29 anesthetized (urethane) New Zealand White rabbits. Capillaries
were visualized with transillumination bright field microscopy (salt
water lens, 50x; resolution 0.3 m). Capillary diameter during control
period had a median value of 4.4 m (range: 3.2-6.9 m). Complete aorta
occlusion resulted in a reduction of femoral artery pressure to a
median value of 17 mmHg (range 4-22 mmHg). During 2 minutes of
occlusion, capillary diameter decreased by 6%, the change on the
arteriolar side of the capillary being larger than that on the
venular side. During reactive hyperemia after release of the
occluder, capillary diameter maximally increased by 12% as compared
to the control period, the arteriolar end of the capillary showing a
larger response than the venular end. Capillary resistance was
estimated to increase by a median value of 27% during occlusion and
to decrease by 36% during peak reactive hyperemia. The observed
diameter changes are compatible with the idea that capillaries change
their diameter relative to changes in transmural pressure.
Received 24 August 1994; accepted in final form 29 March 1995.
APS Manuscript Number H767-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 19 April 1995.