TY - JOUR
T1 - Arterial and cardiopulmonary baroreflexes in 60- to 69- vs. 18- to 36- yr-old humans
AU - Shi, Xiangrong
AU - Gallagher, Kevin M.
AU - Welch-O'Connor, Rita M.
AU - Foresman, Brian H.
PY - 1996/6
Y1 - 1996/6
N2 - This study was designed to test the hypothesis that aging diminished baroreflex function during central hypovolemia. Eleven healthy young and eleven older (age 60-69 yr) individuals were assessed by using heart rate (HR) and mean arterial pressure (MAP) responses to neck pressure and suction during rest and lower body negative pressure (LBNP) of -15 Torr. The slope of forearm vascular resistance to central venous pressure during low-level LBNP was assessed as the index of cardiopulmonary baroreflex sensitivity. Baseline cardiovascular variables were not significantly different between the groups. In addition, there was no group difference in cardiopulmonary baroreflex (- 3.6 vs. -3.7 units/mmHg for young vs. older, respectively) or carotid baroreflex (-0.39 vs. -0.35 beats-min-1 · mmHg-1 and -0.26 vs. -0.35 mmHg/mmHg, for young vs. older, respectively) sensitivity. LBNP did not affect either HR or MAP, whereas it decreased CVP and increased FVR in both groups. LBNP significantly augmented the carotid-HR (-0.47 ± 0.03 beats · min-1 · mmHg-1) and carotid-MAP (-0.42 ± 0.04 mmHg/mmHg) reflex gains in the young subjects only. We concluded that there was no difference in the discrete baroreflex function between the two age groups; however, the interaction of cardiopulmonary baroreceptors with carotid baroreflex function was absent in the older subjects, suggesting that the central integration of afferent neural inputs from the discrete baroreceptors was altered with aging.
AB - This study was designed to test the hypothesis that aging diminished baroreflex function during central hypovolemia. Eleven healthy young and eleven older (age 60-69 yr) individuals were assessed by using heart rate (HR) and mean arterial pressure (MAP) responses to neck pressure and suction during rest and lower body negative pressure (LBNP) of -15 Torr. The slope of forearm vascular resistance to central venous pressure during low-level LBNP was assessed as the index of cardiopulmonary baroreflex sensitivity. Baseline cardiovascular variables were not significantly different between the groups. In addition, there was no group difference in cardiopulmonary baroreflex (- 3.6 vs. -3.7 units/mmHg for young vs. older, respectively) or carotid baroreflex (-0.39 vs. -0.35 beats-min-1 · mmHg-1 and -0.26 vs. -0.35 mmHg/mmHg, for young vs. older, respectively) sensitivity. LBNP did not affect either HR or MAP, whereas it decreased CVP and increased FVR in both groups. LBNP significantly augmented the carotid-HR (-0.47 ± 0.03 beats · min-1 · mmHg-1) and carotid-MAP (-0.42 ± 0.04 mmHg/mmHg) reflex gains in the young subjects only. We concluded that there was no difference in the discrete baroreflex function between the two age groups; however, the interaction of cardiopulmonary baroreceptors with carotid baroreflex function was absent in the older subjects, suggesting that the central integration of afferent neural inputs from the discrete baroreceptors was altered with aging.
KW - aging
KW - central hypovolemia
KW - central venous pressure
KW - forearm vascular resistance
KW - gain
KW - interaction
KW - lower body negative pressure
KW - peripheral venous pressure
UR - http://www.scopus.com/inward/record.url?scp=0030015922&partnerID=8YFLogxK
U2 - 10.1152/jappl.1996.80.6.1903
DO - 10.1152/jappl.1996.80.6.1903
M3 - Article
C2 - 8806893
AN - SCOPUS:0030015922
SN - 8750-7587
VL - 80
SP - 1903
EP - 1910
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 6
ER -