| Summary: | 碩士 === 國防醫學院 === 航太醫學研究所 === 100 === BACKGROUND
Water drinking has profound hemodynamic effects. Water drinking may raises sympathetic nerve activity and blood pressure substantially in patients with autonomic dysfunction and in older subjects. Though the pressor response of water drinking was accentuated, these phenomena also have been observed in the young healthy subjects.
MOTIVATION:
This study further investigated the effects of water drinking on the cardiovascular system by constantly observing the physiology data. Also observe the tyrosine phosphorylation of aquaporin-1 on RBC membrane before and after ingestion water.
METHODS:
A total of 22 healthy subjects were enrolled in this study (with an age of 25.3±3.03 years old, a height of 165.1±8.4 centimeters, a weight of 60.5±8.4 kilograms, and a body mass index (BMI) of 22.1±1.8). In a randomized, controlled, crossover fashion, 22 young healthy subjects ingested either 500 (water session) or 50 mL of water (control). The heart rate, blood pressure, cardiac index, and total peripheral vascular resistance were measured using a Finometer hemodynamic monitor (Finapres blood pressure monitor, model 2300, Ohmeda, Madison, WI, USA), and skin blood flow were measured using DRT4 laser-Doppler perfusion and temperature monitor (Moor Instruments Inc., Wilmington, DE, USA). Blood sampling was performed at 5 minute before, 25 and 50 minutes after either water or control session. Immunoblotting for tyrosine phosphorylation of aquaporin-1 was performed before and after ingestion of either 500 mL or 50 mL water (control) session.
STATISTICAL ANALYSES:
Graphpad Prism 5 software was used to analyze the statistics and diagrams in this study. The differences between two groups were compared by the Student’s T test. The differences between drinking 50ml and 500ml of water were respectively compared to study the effects of water drinking on physiological functions and aquaporin-1 on RBC membrane tyrosine phosphorylation level. The values in diagrams were presented as MeanSD or Mean SEM, and p values <0.05 suggested that there were statistical differences between two groups.
RESULTS:
At time point of 25 minutes after ingestion of 500 mL of water, the total peripheral resistance significantly increased and plasma osmolality decreased after ingestion water. Functional expression of tyrosine phosphorylation of aquaporin-1 on RBC membrane significantly increased at 25 minutes and 50 minutes after ingestion of 500 mL of water than before ingestion of water.
CONCLUSIONS:
We found subjects drinking 500ml of water could accentuate the effect of an increase in systolic blood pressure and total peripheral resistance. And it might associate with sympathetic nervous activity. Furthermore, we also found that after ingested 500 ml water will decrease the osmolality of plasma. The hypotonic environment might upregulated the level of aquaporin-1 tyrosine phosphorylation on RBC membrane.
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