The role of posture on the changes in plasma atrial natriuretic factor and arginine vasopressin levels during immersion |
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Authors: | J P Wolf N U Nguyen A Baulay G Dumoulin S Berthelay |
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Institution: | Laboratoire de Physiologie, Faculté de Médecine, Besan?on, France. |
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Abstract: | In seven healthy male volunteers we investigated changes in plasma atrial natriuretic factor ( ANF]), arginine vasopressin ( AVP]) and plasma volume (PV) during supine immersion. Twenty minutes head-out water immersion in a supine position in a thermo-neutral water bath attenuated the increase in PV induced by 20 min in a supine position in air, but increased the mean plasma ANF] from 32.0 pg.ml-1, SEM 5.1 to 53.3 pg.ml-1, SEM 3.6 and decreased the mean plasma AVP] from 1.4 pg.ml-1, SEM 0.1 to 0.9 pg.ml-1, SEM 0.04. Simultaneously, diuresis and natriuresis increased markedly. During a 20-min control period in the supine posture without immersion, PV, plasma ANF] and AVP] remained unaffected while diuresis and natriuresis did not increase to the same extent. These data suggest that an increase in the central blood volume induced by a weak external hydrostatic pressure during supine immersion triggered the changes in plasma ANF] and AVP] and that the increase was probably due to a shift of blood volume from peripheral to central vessels. The changes in plasma ANF] contributed to the changes in natriuresis. |
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