Published Online
on April 28, 2003

A more recent version of this article appeared on June 1, 2003

This Article Full Text (PDF) All Versions of this Article: 41/6/1234    most recent 01.HYP.0000070957.08219.C9v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tank, J. Articles by Jordan, J. Search for Related Content PubMed PubMed Citation Articles by Tank, J. Articles by Jordan, J. Related Collections Other hypertension Autonomic, reflex, and neurohumoral control of circulation

Submitted on February 10, 2003
Revised on February 28, 2003

Pressor Effect of Water Drinking in Tetraplegic Patients May Be a Spinal Reflex

Jens Tank; Christoph Schroeder; Mandy Stoffels; André Diedrich; Arya M. Sharma; Friedrich C. Luft; and Jens Jordan^*

From Helios-Kliniken-Berlin, Franz Volhard Cardiovascular Research Center, Medical Faculty of the Charité, Humboldt-University (J.T., C.S., M.S., A.M.S., F.C.L., J.J.), Berlin, Germany; and Autonomic Dysfunction Service, Vanderbilt University (A.D.), Nashville, Tenn.

^* To whom correspondence should be addressed. E-mail: jordan{at}fvk-berlin.de.

Abstract--Water drinking elicits a profound sympathetically mediated pressor response in patients with autonomic failure. To further elucidate the mechanism of the response, we assessed the acute effect of drinking water on supine blood pressure and heart rate in 13 tetraplegic patients (12 men, 1 woman; 39±4 years of age; body mass index, 25±1 kg/m²) with complete spinal cord injury (C2 to C7). Heart rate and finger blood pressure were recorded continuously. Brachial blood pressure was measured every 5 minutes. Baroreflex sensitivity was assessed by the sequence method. Stroke volume was calculated by use of transthoracic bioimpedance. Patients were placed in the supine position with the upper body elevated by 15°. After 30 minutes, supine patients ingested 500 mL of water and the following 60 minutes were monitored. Finger blood pressure at baseline was 123±8/65±4 mm Hg. Water drinking elicited a pressor response that was apparent within 5 minutes and reached a maximum of 138±8/73±4 mm Hg after 35 to 40 minutes (P<0.05). Heart rate decreased from 64±2 bpm at baseline to 60±2 bpm (P<0.001). The mean area under the curve for brachial systolic blood pressure changes differed significantly from zero (364±151 mm Hg/min). Total peripheral resistance increased by 15±4% (P<0.05). Baroreflex sensitivity increased from 18±5 ms/mm Hg at baseline to 23±6 ms/mm Hg at 35 minutes after water drinking (P<0.01). Water drinking elicits a pressor response even if the direct connection between brain stem cardiovascular centers and spinal sympathetic neurons is interrupted. This observation might suggest that water drinking activates postganglionic sympathetic neurons either directly or through a spinal reflex mechanism.

Key words: blood pressure • autonomic nervous system • pressoreceptors • reflex

This article has been cited by other articles:

				M. Boschmann, J. Steiniger, G. Franke, A. L. Birkenfeld, F. C. Luft, and J. Jordan Water Drinking Induces Thermogenesis through Osmosensitive Mechanisms J. Clin. Endocrinol. Metab., August 1, 2007; 92(8): 3334 - 3337. [Abstract] [Full Text] [PDF]

				S. R. Raj, I. Biaggioni, B. K. Black, A. Rali, J. Jordan, I. Taneja, P. A. Harris, and D. Robertson Sodium Paradoxically Reduces the Gastropressor Response in Patients With Orthostatic Hypotension Hypertension, August 1, 2006; 48(2): 329 - 334. [Abstract] [Full Text] [PDF]

				A. Lipp, J. Tank, G. Franke, G. Arnold, F. C. Luft, and J. Jordan Osmosensitive mechanisms contribute to the water drinking-induced pressor response in humans Neurology, September 27, 2005; 65(6): 905 - 907. [Abstract] [Full Text] [PDF]

				M. Boschmann, J. Steiniger, U. Hille, J. Tank, F. Adams, A. M. Sharma, S. Klaus, F. C. Luft, and J. Jordan Water-Induced Thermogenesis J. Clin. Endocrinol. Metab., December 1, 2003; 88(12): 6015 - 6019. [Abstract] [Full Text] [PDF]