TY - JOUR
T1 - Carotid baroreflex control of leg vasculature in exercising and non-exercising skeletal muscle in humans
AU - Keller, David Melvin
AU - Fadel, Paul J.
AU - Ogoh, Shigehiko
AU - Brothers, Robert Matthews
AU - Hawkins, Megan
AU - Olivencia-Yurvati, Al
AU - Raven, Peter B.
PY - 2004/11/15
Y1 - 2004/11/15
N2 - Carotid baroreflex (CBR) function was examined in five men and three women (25 ± 1 years) using the variable-pressure neck collar technique at rest and during dynamic, one-legged knee extension exercise at 7 W and 25 W. The CBR exhibited control of leg vascular conductance (LVC) at rest and during exercise in both an exercising leg (EL) and a non-exercising leg (NEL) across a wide range of pressures from +40 Torr neck pressure (NP) to -80 Torr neck suction (NS). Specifically, increases in LVC (% change) in response to NS were no different across -20 to -80 Torr in either EL or NEL compared to rest, P > 0.05. However, CBR-mediated decreases in percentage LVC in response to NP were attenuated in EL at both 7 W (16 ± 1%) and 25 W (12 ± 1%) compared to rest (40 ± 3%; P < 0.05) as well as compared to responses in the NEL (36 ± 6% at 7 W and 36 ± 7% at 25 W; P < 0.05). This decrease in vascular responsiveness in EL was associated with a reduction in the gain of the percentage muscle sympathetic nerve activity (%MSNA)-%LVC relationship compared to rest (P < 0.05). Collectively, these data indicate that, despite a clear attenuation of the vascular response to MSNA in the exercising leg, CBR-mediated changes in mean arterial pressure were no different between rest and exercise.
AB - Carotid baroreflex (CBR) function was examined in five men and three women (25 ± 1 years) using the variable-pressure neck collar technique at rest and during dynamic, one-legged knee extension exercise at 7 W and 25 W. The CBR exhibited control of leg vascular conductance (LVC) at rest and during exercise in both an exercising leg (EL) and a non-exercising leg (NEL) across a wide range of pressures from +40 Torr neck pressure (NP) to -80 Torr neck suction (NS). Specifically, increases in LVC (% change) in response to NS were no different across -20 to -80 Torr in either EL or NEL compared to rest, P > 0.05. However, CBR-mediated decreases in percentage LVC in response to NP were attenuated in EL at both 7 W (16 ± 1%) and 25 W (12 ± 1%) compared to rest (40 ± 3%; P < 0.05) as well as compared to responses in the NEL (36 ± 6% at 7 W and 36 ± 7% at 25 W; P < 0.05). This decrease in vascular responsiveness in EL was associated with a reduction in the gain of the percentage muscle sympathetic nerve activity (%MSNA)-%LVC relationship compared to rest (P < 0.05). Collectively, these data indicate that, despite a clear attenuation of the vascular response to MSNA in the exercising leg, CBR-mediated changes in mean arterial pressure were no different between rest and exercise.
UR - http://www.scopus.com/inward/record.url?scp=9244261014&partnerID=8YFLogxK
U2 - 10.1113/jphysiol.2004.071944
DO - 10.1113/jphysiol.2004.071944
M3 - Article
C2 - 15388778
AN - SCOPUS:9244261014
SN - 0022-3751
VL - 561
SP - 283
EP - 293
JO - Journal of Physiology
JF - Journal of Physiology
IS - 1
ER -