What is Natriuresis: Mechanism and Modulation

It is the excretion of an excessively large amount of sodium in the exceptionally salty urine .

Which is similar to diuresis (excretion of an unusual large amount of urine). It occurs with some diuretics and in some diseases (such as the adrenal glands), leading the person to a loss of salt, a syndrome characterized by dehydration, vomiting, low blood pressure, and the risk of sudden death.

The natriuresis pressure appears dominant physiological mechanism that connects the changes in systemic blood pressure changes in the total amount of sodium in the body.

It also acts by increasing the renal excretion of sodium at the time of entering the blood pressure to the kidneys. The mechanism works completely autonomously within the kidneys and independently of the external hormonal regulation mechanisms.

Its great importance in the connection of renal transport of sodium to blood pressure makes pressure natriuresis the dominant mechanism.

Mechanism

The mechanism of pressure natriuresis is not yet completely clear, however changes in peritubular capillary transport probably underlie its functioning.

As the blood pressure entering the kidneys increases, the hydrostatic pressure within the peritubular capillaries also increases. This causes the Starling force to be reduced due to the resorption of fluid in the capillaries from the renal interstitial fluid.

With the diminution of the peritubular capillary resorption of water and salt a leak appears in the tubule, producing the improved urinary sodium excretion.

Modulation

The relationship between incoming blood pressure and urinary renal sodium excretionin an isolated kidney is quite gradual, therefore pressure natriuresis alone can not explain the accuracy in volume regulation that is normally observed.

It seems that the system of renin, angiotensin, aldosterone (RAAS) is responsible for the provision of pressure natriuresis much more sensitive to blood pressure responses.

Consequently, natriuresis modulated by the RAAS is likely to be the basis of long-term volume and regulation of systemic blood pressure .