Restraint vs hindlimb suspension on fluid and electrolyte balance
in rats.
Bouzeghrane, Fatiha, Sophie Fagette, Laurence Somody, Anne-Marie
Allevard, Claude Gharib, and Guillemette Gauquelin.
Laboratoire de Physiologie de l'Environnement (Groupement
d'Int[acute]er[circumflex]et Public Exercice), Facult[acute]e de
M[acute]edecine Lyon Grange- Blanche, 08 avenue Rockefeller, 69373
LYON cedex 08, France
APStracts 3:0035A, 1996.
To determine the effect of hindlimb suspension on body fluid volume,
salt and water balance, and relevant hormones, 2 series of
experiments were performed on an experimental protocol including
periods of isolation (7 days), horizontal attachment (7 days) and
suspension (14 days). 1/ During the first experiment, water and
electrolyte balance, arginine vasopressin (AVP) and cyclic guanylate
-mono-phosphate (cGMP) were determined in urine, atrial natriuretic
peptide (ANP) in plasma and atria, renin concentration (PRC) and AVP
in plasma on 30 rats. 2/ During the second experiment, blood volume
(BV) and extracellular fluid volume (ECFV) were measured by a
dilution technique (Evan's Blue and Na thiocyanate) on other 30 rats.
We observed a pronounced and early effect of horizontal attachment on
renal variables. After 48h, diuresis (49%), natriuresis (44%),
kaliuresis (36%), osmotic load (39%), creatinine (28%), and AVP
excretion (155%) were significantly increased (p<0.05) in
attached rats. There was no short term (24h) effect of suspension on
urine flow, Na+, K+, creatinine and AVP excretion but the urine cGMP
decreased significantly (45% p<0.05). Significant decreases in
natriuresis, kaliuresis, urine creatinine and osmotic load occured in
the suspension group, 7 days after suspension. After the 14-day-tail
-suspension, PV and ECFVmeasured in suspended rats were not different
from isolated rat values, whereas PV increased by 15% (p<0.05)
in the attached rats : plasma immunoreactive ANP levels of suspended
rats were significantly reduced by 35% (p<0.001) vs isolated
rats and by 18% (p<0.05) vs attached rats. Using this
experimental protocol, the physiological alterations revealed that
suspension produce some acute and long term effects but the fixation
to the suspension device, restraint and confinement have their own
influence on fluid distribution and renal function.
Received 15 February 1995; accepted in final form 4 January 1996.
APS Manuscript Number A181-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 January 96