TY - JOUR
T1 - Dissociation between volume blood flow and laser-Doppler signal from rat muscle during changes in vascular tone
AU - Kuznetsova, Larisa V.
AU - Tomasek, Nicole
AU - Sigurdsson, Gisli H.
AU - Banic, Andrej
AU - Erni, Dominique
AU - Wheatley, Anthony M.
PY - 1998/4
Y1 - 1998/4
N2 - Although the laser-Doppler flowmetry (LDF) signal from skeletal muscle has been shown to provide a good measure of blood flow under some conditions, its behavior during administration of vasoactive substances has never been addressed. The aims of this study were to compare 1) changes in LDF signal with those in total muscle blood flow measured with radioactive microspheres after ganglionic blockade (chlorisondamine) and during administration of angiotensin II (ANG II), phenylephrine (PE), and isoproterenol (Iso) and 2) changes in vascular resistance estimated by the two techniques. The LDF signal from the biceps femoris muscle was investigated in anesthetized male Wistar rats. Ganglionic blockade led to a significant (P < 0.05) fall in mean arterial pressure (MAP) [medians (lower, upper quartiles): 78 (72, 83) vs. 127 (114, 138) mmHg under basal conditions], muscle blood flow (MBF, microsphere technique; 61%), and the LDF signal (29%). Muscle vascular resistance (MVR = MAP/MBF) was increased (64%, P < 0.05), but vascular resistance estimated as MAP/LDF signal (MVR(LDF)) was unchanged. During ANG II and PE infusions, MAP rose (P < 0.05) to 178 (155, 194) and 127 (124, 142) mmHg, respectively; MBF did not change compared with the preinfusion (postganglionic blockade) level and remained significantly (P < 0.05) lower than baseline, whereas the LDF signal increased up to a level not different from baseline. MVR rose and was significantly (P < 0.05) higher than baseline, whereas MVR(LDF) did not differ significantly from baseline. During Iso infusion, MAP fell [58 (56, 60) vs. 94 (92, 102) mmHg, P < 0.05], the LDF signal was reduced (49%, P < 0.05) despite a large increase in MBF (139%, P < 0.05), and MVR fell (74%, P < 0.05), whereas MVR(LDF) did not change vs. preinfusion level. Our results suggest that 1) changes in the LDF signal from muscle may not correlate with changes in total muscle blood flow measured by the microsphere technique during infusion of vasoactive substances and 2) the use of LDF data for estimation of MVR during changes in vascular tone in rat skeletal muscle is probably not appropriate.
AB - Although the laser-Doppler flowmetry (LDF) signal from skeletal muscle has been shown to provide a good measure of blood flow under some conditions, its behavior during administration of vasoactive substances has never been addressed. The aims of this study were to compare 1) changes in LDF signal with those in total muscle blood flow measured with radioactive microspheres after ganglionic blockade (chlorisondamine) and during administration of angiotensin II (ANG II), phenylephrine (PE), and isoproterenol (Iso) and 2) changes in vascular resistance estimated by the two techniques. The LDF signal from the biceps femoris muscle was investigated in anesthetized male Wistar rats. Ganglionic blockade led to a significant (P < 0.05) fall in mean arterial pressure (MAP) [medians (lower, upper quartiles): 78 (72, 83) vs. 127 (114, 138) mmHg under basal conditions], muscle blood flow (MBF, microsphere technique; 61%), and the LDF signal (29%). Muscle vascular resistance (MVR = MAP/MBF) was increased (64%, P < 0.05), but vascular resistance estimated as MAP/LDF signal (MVR(LDF)) was unchanged. During ANG II and PE infusions, MAP rose (P < 0.05) to 178 (155, 194) and 127 (124, 142) mmHg, respectively; MBF did not change compared with the preinfusion (postganglionic blockade) level and remained significantly (P < 0.05) lower than baseline, whereas the LDF signal increased up to a level not different from baseline. MVR rose and was significantly (P < 0.05) higher than baseline, whereas MVR(LDF) did not differ significantly from baseline. During Iso infusion, MAP fell [58 (56, 60) vs. 94 (92, 102) mmHg, P < 0.05], the LDF signal was reduced (49%, P < 0.05) despite a large increase in MBF (139%, P < 0.05), and MVR fell (74%, P < 0.05), whereas MVR(LDF) did not change vs. preinfusion level. Our results suggest that 1) changes in the LDF signal from muscle may not correlate with changes in total muscle blood flow measured by the microsphere technique during infusion of vasoactive substances and 2) the use of LDF data for estimation of MVR during changes in vascular tone in rat skeletal muscle is probably not appropriate.
KW - Angiotensin II
KW - Isoproterenol
KW - Phenylephrine
KW - Radioactive microspheres
KW - Vascular resistance
KW - Vasoconstriction
KW - Vasodilation
UR - https://www.scopus.com/pages/publications/0031922663
U2 - 10.1152/ajpheart.1998.274.4.h1248
DO - 10.1152/ajpheart.1998.274.4.h1248
M3 - Article
C2 - 9575928
AN - SCOPUS:0031922663
SN - 0363-6135
VL - 274
SP - H1248-H1254
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 4 43-4
ER -