The purpose of this study was to compare the effectiveness of saline load to @entity7842 (florinef) as countermeasures for reduced @entity8450 and orthostatic intolerance after spaceflight. Eleven males (ages 30-50 yr) underwent a 3-day ambulatory baseline period followed by 7 days of 6 degrees head-down bedrest, during which cardiopulmonary and arterial baroreflex sensitivity and @entity8450 ( @entity8450 ) were determined. During pre-bedrest and 2.5 h after treatment on day 8, @entity8450 was also measured and subjects underwent a 15-min unsupported stand test. Treatments consisted of 8 salt tablets (1 g @entity1219 per tablet) and 960 ml of water in 5 subjects and 0.6 mg (0.2 mg x 3) over 24 h in the other 6 subjects. @entity8450 decreased by 12% on day 7 of bedrest. This was restored on day 8 by florinef but not by saline load. The effect of florinef on @entity8450 was paralleled by decreases in urine volume and the urinary @entity1372 / @entity972 ratio. Reduced @entity8450 was associated with greater vascular resistance for the same drop in central venous pressure, suggesting less vasoconstriction reserve after bedrest. Carotid baroreflex control of heart rate was attenuated after 7 days of bedrest. Both baroreflex functions were restored by florinef but not saline load. Only 1 of 6 subjects showed @entity1163 in the florinef-treated group, whereas 4 of 5 subjects did so in the saline-load group. Acute florinef treatment appears to have distinct advantages as a protective measure for post-bedrest orthostatic intolerance, not only through its salt retaining, volume-expanding mineralcorticoid effect, but possibly through its actions on baroreflex and sympathetic functions.

Advantages and disadvantages of XXXX or saline load in preventing post-spaceflight orthostatic hypotension.

@entity1219 :: ('CHEBI:26710', 'Chemical') :: ['NaCl'] @entity1372 :: ('MESH:D012964', 'Chemical') :: ['sodium'] @entity1163 :: ('MESH:D013575', 'Disease') :: ['syncopal symptoms'] @entity972 :: ('MESH:D011188', 'Chemical') :: ['potassium'] @entity8450 :: ('MESH:D054219', 'Disease') :: ['plasma volume', 'PV'] @entity7842 :: ('MESH:D005438', 'Chemical') :: ['fludrocortisone']
@entity7842 :: (MESH:D005438,Chemical) :: ['fludrocortisone']
