The relationship between microvessel and tissue blood flow (BF) was determined with two different techniques during changes in local vasomotor tone in the rat cremaster muscle. Whole organ and regional BF were measured with the radioactive microsphere technique (BF(ms)) and compared with values calculated in individual arterioles (BF(c)) using the dual-slit cross-correlation technique. In the muscle prepared for microcirculatory observation (i.e., dissected, surgically divided into a flattened sheet, and covered with clear plastic), resulting BF(ms) was 43 ± 3 ml·min-1. 100 g-1, which was significantly higher than paired BF(ms) in the contralateral undisturbed muscle (24 ± 7 ml·min-1·100 g-1). Over a range in vasomotor tone, regional BF(ms) to the edge of the tissue, which was exposed to the trauma of the surgery, was 56 ± 7 ml·min-1·100 g-1 compared with 38 ± 5 in the less traumatized center region, a significant difference of 79 ± 31%. There was no linear relationship between arteriolar BF(c) and BF(ms). The correlation was not improved if the factors of vessel size, vasomotor tone, animal size, or muscle size were considered. Changes in arteriolar BF(c) (γ) overestimated changes in total tissue BF(ms) (χ) by a factor of 2 (γ) = 2.01χ - 0.6; r= 0.86), but changes in arteriolar BF(c) were proportional to changes in BF(ms) if only the center region (χ) of the tissue was considered (γ = 1.08χ - 0.1; r = 0.84). The general implication from these results is that factors that influence perfusion heterogeneity, such as surgical trauma, should be carefully considered when correlating macro- and microcirculatory measurements of BF.
|Original language||English (US)|
|Journal||American Journal of Physiology - Heart and Circulatory Physiology|
|State||Published - 1985|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Physiology (medical)