Linked Life Data

9719058

Source:http://linkedlifedata.com/resource/pubmed/id/9719058

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-9-9
pubmed:abstractText
Based on observations of smaller increases in limb vascular resistance during acute incremental hypovolemia in older adults, cardiopulmonary and integrative (combined cardiopulmonary and arterial) baroreflex control of sympatho-circulatory function is thought to be impaired with aging in humans. We tested this hypothesis directly by making intraneural measurements of skeletal muscle sympathetic nerve activity (MSNA; peroneal microneurography) in groups of young (23+/-1 years; n=11) and older (64+/-1 years; n=12) healthy adult men during progressive hypovolemia produced by graded (-5 to -40 mm Hg) lower body negative pressure (LBNP). Baseline levels of MSNA and arterial blood pressure were higher and heart rate was lower in the older subjects (P<0.05). Lower levels of LBNP (-5 to -20 mm Hg) did not affect arterial blood pressure or heart rate in either group; systolic and pulse pressures declined during higher levels of LBNP (-30 and -40 mm Hg) but only in the young subjects (P<0.05). Graded LBNP evoked progressive, linear reductions in peripheral venous pressure (PVP) and increases in MSNA, plasma norepinephrine concentration (PNE), and forearm vascular resistance (FVR) in both groups (all P<0.05). DeltaMSNA/ deltaPVP was approximately 150% greater in the older versus young men during both lower and higher levels of hypovolemia (P<0.01); however, deltaFVR/deltaPVP was approximately 50% smaller in the older men (P<0.05). There was no difference in the MSNA-PNE relation with age, but deltaFVR/deltaMSNA was approximately 65% to 70% smaller in the older subjects (P<0.05). Our findings indicate that cardiopulmonary and integrative baroreflex control of central sympathetic outflow during hypovolemia is augmented, not impaired, with age in healthy humans. However, the reflex-mediated increases in limb vascular resistance during hypovolemia are smaller in older adults because of attenuated vasoconstrictor responsiveness to sympathetic stimulation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0194-911X
pubmed:author
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
298-304
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Augmented cardiopulmonary and integrative sympathetic baroreflexes but attenuated peripheral vasoconstriction with age.
pubmed:affiliation
Center for Physical Activity, Disease Prevention, and Aging, Department of Kinesiology, University of Colorado at Boulder, USA. davy@cahs.colostate.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.