Spaceflight regulates ryanodine receptor subtype 1 in portal vein myocytes in the opposite way of hypertension

Fabrice Dabertrand, Yves Porte, Nathalie Macrez, Jean-Luc Morel
Journal of Applied Physiology. 2012-02-01; 112(3): 471-480
DOI: 10.1152/japplphysiol.00733.2011

Lire sur PubMed

1. J Appl Physiol (1985). 2012 Feb;112(3):471-80. doi:
10.1152/japplphysiol.00733.2011. Epub 2011 Nov 17.

Spaceflight regulates ryanodine receptor subtype 1 in portal vein myocytes in the
opposite way of hypertension.

Dabertrand F(1), Porte Y, Macrez N, Morel JL.

Author information:
(1)Universite de Bordeaux, Institut des Maladies Neurodégénératives, Bordeaux,

Gravity has a structural role for living systems. Tissue development,
architecture, and organization are modified when the gravity vector is changed.
In particular, microgravity induces a redistribution of blood volume and thus
pressure in the astronaut body, abolishing an upright blood pressure gradient,
inducing orthostatic hypotension. The present study was designed to investigate
whether isolated vascular smooth muscle cells are directly sensitive to altered
gravitational forces and, second, whether sustained blood pressure changes act on
the same molecular target. Exposure to microgravity during 8 days in the
International Space Station induced the decrease of ryanodine receptor subtype 1
expression in primary cultured myocytes from rat hepatic portal vein. Identical
results were found in portal vein from mice exposed to microgravity during an
8-day shuttle spaceflight. To evaluate the functional consequences of this
physiological adaptation, we have compared evoked calcium signals obtained in
myocytes from hindlimb unloaded rats, in which the shift of blood pressure mimics
the one produced by the microgravity, with those obtained in myocytes from rats
injected with antisense oligonucleotide directed against ryanodine receptor
subtype 1. In both conditions, calcium signals implicating calcium-induced
calcium release were significantly decreased. In contrast, in spontaneous
hypertensive rat, an increase in ryanodine receptor subtype 1 expression was
observed as well as the calcium-induced calcium release mechanism. Taken
together, our results shown that myocytes were directly sensitive to gravity
level and that they adapt their calcium signaling pathways to pressure by the
regulation of the ryanodine receptor subtype 1 expression.

DOI: 10.1152/japplphysiol.00733.2011
PMID: 22096120 [Indexed for MEDLINE]

Auteurs Bordeaux Neurocampus