Format

Send to

Choose Destination
Eur J Clin Invest. 2015 Jul;45(7):679-85. doi: 10.1111/eci.12455. Epub 2015 Jun 15.

Influence of bed rest on plasma galanin and adrenomedullin at presyncope.

Author information

1
Gravitational Physiology and Medicine research unit, Institute of Physiology, Medical University of Graz, Graz, Austria.
2
Centre of Human & Aerospace Physiological Sciences, King's College London, London, UK.
3
German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany.
4
Department of Biosciences, Biotechnologies and Biopharmaceutics University of Bari, Bari, Italy.

Abstract

BACKGROUND:

The role of hormones in reduced orthostatic tolerance following long-term immobilization remains uncertain. We have previously shown that plasma concentrations of adrenomedullin and galanin, two peptides with vasodepressor properties, rise significantly during orthostatic challenge. We tested the hypothesis that bedrest immobilization increases the rise in adrenomedullin and galanin during orthostatic challenge leading to presyncope.

MATERIALS AND METHODS:

We measured baseline (supine), presyncope and recovery (10 min postpresyncope, supine) levels of adrenomedullin and galanin in 8 healthy men, before and after 21 days of -6° head-down bed rest (HDBR). Presyncope was elicited using a combined head-up tilt and graded lower body negative pressure protocol. Orthostatic tolerance was defined as the time taken from the commencement of head-up tilt to the development of presyncope.

RESULTS:

Orthostatic tolerance time after HDBR reduced by 8·36 ± 5·39 min (P = 0·0032). HDBR increased plasma adrenomedullin concentration to orthostatic challenge (P = 0·0367). Compared to pre-HDBR, a significant rise in post-HDBR presyncopal (P < 0·001) and recovery adrenomedullin concentration (P < 0·01) was demonstrated. In contrast, we observed no change in pre- and post-HDBR galanin levels to orthostatic challenge.

CONCLUSIONS:

Bedrest immobilization appears to affect adrenomedullin levels in that greater increases in adrenomedullin occur at presyncope following bedrest immobilization. Due to its peripheral vasculature hypotensive effect, the greater levels of adrenomedullin at presyncope following bedrest immobilization may have contributed to the reduced orthostatic capacity postbedrest.

KEYWORDS:

Head-up tilt; lower body negative pressure; orthostatic challenge; syncope

PMID:
25912957
DOI:
10.1111/eci.12455
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center