Vascular resistance vs. perfusate osmolarity: the short term microvascular effect of hypotonic and hypertonic perfusion in the isolated kidney.
Vascular resistance changes were measured in response to alteration in perfusate osmolarity in isolated rabbit kidneys perfused at 10 degrees C. The data obtained were found to fit a simple mathematical model of the vascular resistance of the microcirculation in which it was assumed that variation in this parameter depended solely upon osmotic alterations in the size of the cells within and around the blood vessel walls. The model predicts that the volumetric changes due to the different osmolarities are produced in a tissue layer whose thickness is 30% relative to a fixed outer radius. This result is compatible with the hypothesis that the effects are predominantly due to changes of endothelial cell volume and other perivascular capillary cells. The analysis illustrates the significance of perfusate osmolarity as a determinant of vascular resistance, can be used to investigate the hemodynamic effects that occur during the introduction and removal of cryoprotective agents, and is relevant to the interpretation of results obtained with hypertonic solutions in blood volume restoration after hypovolemic shock.
Department of Surgery, Veterans Administration Medical Center, San Diego, California 92161.
G M
GM
Collins
A R
AR
Hargens
W N
WN
Wicomb
M
M
Intaglietta
N A
NA
Halasz
D000818:Animals; D006982:Hypertonic Solutions; D007038:Hypotonic Solutions; D007668:Kidney / Q000098:blood supply*; D008833:Microcirculation / Q000187:drug effects; D008955:Models, Cardiovascular; D008962:Models, Theoretical; D009994:Osmolar Concentration; D010477:Perfusion; D011817:Rabbits; D014655:Vascular Resistance
D006982:Hypertonic Solutions; D007038:Hypotonic Solutions