Interrelationships Between the Renin-Angiotensin-Aldosterone System and Sympathetic and Dopaminergic Activities in Elderly Subjects

Abstract

The interrelationships between the renin-aldosterone system and the sympathetic and dopaminergic activities were studied by measuring the plasma renin activity (PRA), plasma aldosterone concentration (PAC), serum prolactin (PRL) concentration, and 24 hr-urinary excretions of adrenaline (Ad), noradrenaline (NA) and dopamine (DA) in elderly normotensive subjects aged 60 to 90 yrs.

The PAC showed a significant correlation with NA in the urine (γ = 0.694, n = 24, p < 0.001). The PRA also tended to correlate with NA in the urine, although the degree was weak and not significant. The serum PRL concentration showed a significant correlation with DA in the urine (γ = 0.447, n = 24, p < 0.05). No significant correlation was observed between DA and PRA or PAC, and between the serum PRL concentration and PRA or PAC.

From these results, it is shown that the renin-aldosterone system has a relation to urinary NA excretion, and the existence of an interrelationship between the central dopaminergic activity and urinary DA excretion is suggested.

Key Words:

• Adrenaline
• noradrenaline
• dopamine
• renin-aldosterone system
• serum prolactin concentration