TY - JOUR
T1 - Effects of changes in central blood volume on carotid-vasomotor baroreflex sensitivity at rest and during exercise
AU - Ogoh, Shigehiko
AU - Brothers, R. Matthew
AU - Barnes, Quinton
AU - Eubank, Wendy L.
AU - Hawkins, Megan N.
AU - Purkayastha, Sushmita
AU - O-Yurvati, Albert
AU - Raven, Peter B.
PY - 2006
Y1 - 2006
N2 - The purpose of this investigation was to examine whether the effect of changes in central blood volume on carotid-vasomotor baroreflex sensitivity at rest was the same during exercise. Eight men (means ± SE: age 26 ± 1 yr; height 180 ± 3 cm; weight 86 ± 6 kg) participated in the present study. Sixteen Torr of lower body negative pressure (LBNP) were applied to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak O2 uptake (104 ± 20 W). Subsequently, infusions of 25% human serum albumin solution were administered to increase CVP at rest and during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, the maximal gain (Gmax) of the carotid-vasomotor baroreflex function curve was measured using the neck pressure and neck suction technique. LBNP reduced CVP and increased the Gmax of the carotid-vasomotor baroreflex function curve at rest (+63 ± 25%, P = 0.006) and during exercise (+69 ± 19%, P = 0.002). In contrast to the LBNP, increases in CVP resulted in the Gmax of the carotid-vasomotor baroreflex function curve being decreased at rest -8 ± 4% and during exercise -18 ± 5% (P > 0.05). These findings indicate that the relationship between CVP and carotid-vasomotor baroreflex sensitivity was nonlinear at rest and during exercise and suggests a saturation load of the cardiopulmonary baroreceptors at which carotid-vasomotor baroreflex sensitivity remains unchanged.
AB - The purpose of this investigation was to examine whether the effect of changes in central blood volume on carotid-vasomotor baroreflex sensitivity at rest was the same during exercise. Eight men (means ± SE: age 26 ± 1 yr; height 180 ± 3 cm; weight 86 ± 6 kg) participated in the present study. Sixteen Torr of lower body negative pressure (LBNP) were applied to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak O2 uptake (104 ± 20 W). Subsequently, infusions of 25% human serum albumin solution were administered to increase CVP at rest and during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, the maximal gain (Gmax) of the carotid-vasomotor baroreflex function curve was measured using the neck pressure and neck suction technique. LBNP reduced CVP and increased the Gmax of the carotid-vasomotor baroreflex function curve at rest (+63 ± 25%, P = 0.006) and during exercise (+69 ± 19%, P = 0.002). In contrast to the LBNP, increases in CVP resulted in the Gmax of the carotid-vasomotor baroreflex function curve being decreased at rest -8 ± 4% and during exercise -18 ± 5% (P > 0.05). These findings indicate that the relationship between CVP and carotid-vasomotor baroreflex sensitivity was nonlinear at rest and during exercise and suggests a saturation load of the cardiopulmonary baroreceptors at which carotid-vasomotor baroreflex sensitivity remains unchanged.
KW - Arterial blood pressure
KW - Cardiopulmonary baroreceptors
KW - Central venous pressure
UR - http://www.scopus.com/inward/record.url?scp=33745866590&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.01452.2005
DO - 10.1152/japplphysiol.01452.2005
M3 - Article
C2 - 16575020
AN - SCOPUS:33745866590
SN - 8750-7587
VL - 101
SP - 68
EP - 75
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 1
ER -