BACKGROUND: Water drinking elicits a sympathetically mediated pressor response in multiple-system atrophy patients through an unknown mechanism. We reasoned that gastrointestinal distention, hyposomotic stimulation, or both contribute to the water-induced pressor response. METHODS: We compared the response to normal saline and water on blood pressure in 10 patients with probable multiple-system atrophy. Patients featured moderate to severe autonomic dysfunction. EKG and finger arterial blood pressure were recorded continuously, and 500 mL normal saline and distilled water were each given in a single-blinded fashion. Fluids were applied through a previously inserted nasogastric tube within a 5-minute period. RESULTS: Blood pressure began to increase within 10 minutes after water administration and reached a maximum after 20 minutes. Blood pressure did not change after saline administration. The blood pressure change after 20 minutes was 8 +/- 9/2 +/- 5 mmHg with water and -1 +/- 11/-1 +/- 7 mmHg with normal saline administration (p = 0.02 between interventions). Heart rate did not change with either intervention. CONCLUSION: Ingestion of water elicits a greater pressor response than the ingestion of normal saline. Thus, gastric distention is probably not the crucial mechanisms for the water-induced pressor response. Instead, the response may be mediated through osmosensitive afferent structures in the gastrointestinal tract, portal vein, and liver.
BACKGROUND:Water drinking elicits a sympathetically mediated pressor response in multiple-system atrophypatients through an unknown mechanism. We reasoned that gastrointestinal distention, hyposomotic stimulation, or both contribute to the water-induced pressor response. METHODS: We compared the response to normal saline and water on blood pressure in 10 patients with probable multiple-system atrophy. Patients featured moderate to severe autonomic dysfunction. EKG and finger arterial blood pressure were recorded continuously, and 500 mL normal saline and distilled water were each given in a single-blinded fashion. Fluids were applied through a previously inserted nasogastric tube within a 5-minute period. RESULTS: Blood pressure began to increase within 10 minutes after water administration and reached a maximum after 20 minutes. Blood pressure did not change after saline administration. The blood pressure change after 20 minutes was 8 +/- 9/2 +/- 5 mmHg with water and -1 +/- 11/-1 +/- 7 mmHg with normal saline administration (p = 0.02 between interventions). Heart rate did not change with either intervention. CONCLUSION: Ingestion of water elicits a greater pressor response than the ingestion of normal saline. Thus, gastric distention is probably not the crucial mechanisms for the water-induced pressor response. Instead, the response may be mediated through osmosensitive afferent structures in the gastrointestinal tract, portal vein, and liver.
Authors: Lauro C Vianna; Ricardo B Oliveira; Bruno M Silva; Djalma R Ricardo; Claudio Gil S Araújo Journal: Eur J Appl Physiol Date: 2007-10-10 Impact factor: 3.078
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Authors: Andrea Galli; Franca Barbic; Marta Borella; Giorgio Costantino; Francesca Perego; Franca Dipaola; Francesco Casella; Pier Giorgio Duca; Andrè Diedrich; Satish Raj; David Robertson; Alberto Porta; Raffaello Furlan Journal: PLoS One Date: 2011-07-27 Impact factor: 3.240
Authors: Marcus May; Faikah Gueler; Hannelore Barg-Hock; Karl-Heinz Heiringhoff; Stefan Engeli; Karsten Heusser; André Diedrich; André Brandt; Christian P Strassburg; Jens Tank; Fred C G J Sweep; Jens Jordan Journal: PLoS One Date: 2011-10-07 Impact factor: 3.240