Isosmotic decreases in central venous pressure do not stimulate arginine vasopressin (AVP) secretion in normal humans, while symptomatic vasovagal hypotension produces large rises in plasma AVP levels. The effects of an asymptomatic fall in arterial pressure on plasma AVP in humans are poorly documented. Heart rate, mean arterial pressure, plasma osmolality, and plasma AVP were measured in seven healthy volunteers during infusion of sodium nitroprusside on two occasions, with and without central venous pressure measurements. On both study days, heart rate increases (5 ± 3 and 8 ± 4 beats/min) and mean arterial pressure reductions (12 ± 3 and 13 ± 2.0 mm Hg) were comparable. Plasma AVP (3.2 ± 1.4 and 4.0 ± 1.7 pg/ml at control) did not change on either study day after nitroprusside titration (30-40 minutes) or after an additional 90 minute observation on the first day. When measured on the second day, central venous pressure declined from 5.6 ± 1.9 to 2.9 ± 1.5 mm Hg, p < .001. Osmolality was constant on both days at all times. Unloading of sinoaortic baroreceptors produced by asymptomatic hypotension, coupled with a moderate reduction in central venous pressure, does not, therefore, stimulate plasma AVP secretion in normal humans. This observation has relevance to understanding the mechanisms involved in the reported increases in plasma AVP during orthostatic stress and in various diseases.
|Original language||English (US)|
|Number of pages||4|
|Journal||American Journal of the Medical Sciences|
|State||Published - 1989|
Bibliographical noteFunding Information:
From the Hennepin County Medical Center and the University of Minnesota Medical School, Minneapolis, Minnesota. This work was carried out during Dr. Goldsmith's tenure as a recipient of Clinical Investigator Award #K08HL00895 from the National Heart, Lung, and Blood Institute, which provided support for this research. The author would like to thank Ms. Donna Dodge-Brown for help in conducting the studies, Dr. Allen Cowley for providing the ~aso pressin assays and for his review of the manuscript, Dr. Ada SImon for performing the norepinephrine assay and Rebecca Hennessey for preparing of the manuscript. . . Reprints: Steven Goldsmith, MD, Hennepin County MedIcal Center, 701 Park Avenue South, Minneapolis, MN 55415.