engleski

Adrenergic system responses to acute salt loading in healthy individuals

Increased activation of renin-angiotensin system (RAS) and elevated sympathetic nervous activity (SNA) are well-established hallmarks of arterial hypertension (AH). Also, there is a strong positive correlation between high-salt (HS) intake and elevated blood pressure (BP) levels, which consequently leads to the development and progression of AH. A growing body of evidence indicates that HS intake is highly detrimental to vascular and endothelial function, even in the absence of arterial BP changes. Studies in healthy individuals reported that inhibition of the RAS and oxidative dis-balance have important role in HS diet-induced impairment of endothelial and microvascular function. Still, how the HS intake affects autonomic nervous system (ANS) activity in healthy individuals (inhibits or potentiate SNA), and whether these changes could be functionally associated with altered microvascular and endothelial function is still not elucidated. A set of experiments that included both functional and biochemical assessment of the ANS activity by 5-minute measurement of heart rate variability (HRV) and measurement of catecholamine’s concentration in a 24h urine sample was performed before and after a 7-day HS diet (around 14 g of salt/day) in healthy young individuals. The 7-day HS diet did not induce a statistically significant change in the parameters obtained by time-domain analysis of HRV measurement (SDNN, RMS-SD, pNN50). The frequency-domain interpretation of HRV measurement (considered more suitable for 5-min HRV) showed a slightly reduced (but not statistically significant) LF/HF ratio (ratio of sympathetic and parasympathetic activity) following the HS diet (trend?). 24h urine adrenaline, metanephrine, and normetanephrine concentrations were significantly reduced following 7-day HS diet in healthy individuals. These results may suggest that the 7-day HS diet has tendency to modulate ANS balance by shifting it towards parasympathetic dominance. Still, what is the potential mechanisms that mediate this change, and whether this modulation of ANS balance is potentially associated with changes in endothelial microvascular function in healthy individuals remains to be elucidated in further studies. (HRZZ IP-2016-06-8744 RAS-AdrenOX).

high salt diet ; adrenergic system ; heart rate variability ; catecholamines

nije evidentirano