A Low Protein Diet Causes an Increase in the Basal Levels and Variability of Mean Arterial Pressure and Heart Rate in Fisher Rats

Abstract

The correlation between nutrition and cardiovascular related disorders is a well-established fact. Previous work from our Laboratory has suggested a significant compromise of cardiovascular reflexes in conscious rats submitted to a low-protein (LP) diet. Our working hypothesis is that the basal level of mean arterial pressure (MAP), variability of the mean arterial pressure (VMAP), heart rate (HR) and variability of heart rate (VHR) are altered in rats submitted to a protein restricted diet. Two experimental groups were used: control group (normal protein 15%, NP) and malnourished group (low-protein 6%, LP). In order to verify the efficiency of the dietary restriction we measured body weight, total blood protein, plasma albumin, urea and glucose. Our experiments demonstrated that the malnourished rats presented augment levels of basal MAP (LP 122±2 mmHg vs. NP 113±1 mmHg) and of VMAP (LP 12.8±1.5 mmHg vs. NP 9±1 mmHg) when compared to the control group. We observed similar increased levels, in the malnourished group, for both HR (LP 429±8 bpm vs. NP 381±7 bpm) and VHR (LP 67.6±8.3 bpm vs. NP 44.4±4.9 bpm). Our results suggest a correlation between the LP diet in Fisher rats and the increased basal levels of mean arterial pressure, HR and their respective variability.

Keywords:

• Protein restriction
• Arterial hypertension
• Mean arterial pressure variability
• Heart rate variability