Sympathetic control of hemodynamics during moderate head-up tilt in human subjects

To confirm sympathetic control of hemodynamics during postural change, sympathetic nerve activity supplying the anterior tibial muscle (MSNA) was measured by microneurography and muscle blood flow (MBF) by the xenon washout method during graded head-up tilt from 0 degrees horizontal to 30 degrees in...

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Bibliographic Details
Published inEnvironmental medicine : annual report of the Research Institute of Environmental Medicine, Nagoya University Vol. 41; no. 2; p. 151
Main Authors Saito, M, Foldager, N, Mano, T, Iwase, S, Sugiyama, Y, Oshima, M
Format Journal Article
LanguageEnglish
Published Japan 01.12.1997
Subjects
Adult
Blood Pressure - physiology
Head-Down Tilt
Heart Rate - physiology
Hemodynamics - physiology
Humans
Male
Muscle, Skeletal - blood supply
Muscle, Skeletal - innervation
Muscle, Skeletal - physiology
Peroneal Nerve - physiology
Posture - physiology
Regional Blood Flow
Sympathetic Nervous System - physiology
Tilt-Table Test
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Summary:To confirm sympathetic control of hemodynamics during postural change, sympathetic nerve activity supplying the anterior tibial muscle (MSNA) was measured by microneurography and muscle blood flow (MBF) by the xenon washout method during graded head-up tilt from 0 degrees horizontal to 30 degrees in 5 degrees increments. MSNA was represented as the increase in burst rate with increased tilt angle. The increments of MSNA from 0 degree horizontal were statistically significant at all tilt angles. MBF decreased gradually with increasing tilt angle, with no difference noted from 5 to 15 degrees, but a significant decrease between 20 and 30 degrees. Mean blood pressure remained unchanged during graded tilt. The heart rate did not increase until a tilt angle of 10 degrees, with increments becoming significant beyond 15 degrees. These results demonstrated that MSNA plays an important role in hemodynamic regulation during incremental changes in posture, while tilt angle increased HR and other control mechanisms that may be involves.
ISSN:0287-0517