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carlos marques-neves, sofia vaz, isabel rocha; Cardiovascular, Ocular And Autonomic Characterization Of The Water Drinking Test In The Anesthetized Rat. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1522.
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Develop an experimental model to evaluate the responses triggered by the water drinking test (WDT) in terms of the cardiovascular, ocular and autonomic systems
43 Wistar rats, aged 4 months ± 2 weeks.The animals were anaesthetized, and neuromuscular blockage, with artificial ventilation.The blood pressure was monitoring by femoral artery catheterization and Intraocular pressure by direct manometric measurement.EKG was taken, An orogastric probe was inserted for the administration of the water bolus.A water bolus of 2.85 ml per kg of body weight water (38 ° C) was administrated, with intervals of 10 minutes.The signals analysis was performed off-line, with LabChart 6 ®. For the time-frequency domain analysis, MatLab R2009b ® and FisioSinal ® software were used. The statistical analysis were performed with GraphPad InStat ® and GraphPad Prism ®. The t -Student test was used for paired data and values were considered significant when p <0.05.Results were expressed as mean ± standard deviation.
In 43 experiences, 55 boluses were validated. The early response occurred approximately 4.5 seconds after the bolus and it was maintained for 10 seconds. The IOP response reached its maximum value during the bolus first than BP, but IOP took longer to return to baseline.The BP change from 122.18 to 156.57 mmHg (p<0.0001) and IOP from 14.88 to 16.02 mmHg (p<0.0001). The Perfusion pressure increased from 102.87 to 121.74 mmHg (p<0.0001). The HR went from 430.34 to 423.09 ppm (p<0.0001). At baseline, there was a moderate correlation (ρ> 0.30) and a significant p-value between BP and IOP, PP and HR. During the bolus, the correlation between IOP and BP and HR was also moderate, but there was a strong correlation (ρ> 0.70) between BP and PP. Since there was a positive correlation between BP and IOP, PP and HR, these variables are dependent and therefore vary similarly. By linear regression analysis, the variation of PP and HR was very dependent on the PA, as r approaches 1. Considering the time-frequency analysis the BP balance LF/HF (low frequency / high frequency) (symphatetic/parasympathetic activity) after the bolus analyzed by FFT and Wavelet determined a positive relationship with an increase of 132.32% (p = 0.0032) and 163.90% (p <0.0001), respectively. The analysis of IOP by FFT and Wavelet revealed that the LF/HF ratio increases with the water bolus 7.50% (p = 0.0013) and 58.54% (p = 0.0235), respectively.
The WDT causes cardiovascular, ocular and autonomic changes in rats,The increase in BP and IOP is due to a possible sympathetic activation
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