Mechanism of Action
Blood pressure and fluid and electrolyte homeostasis is regulated by the renin-angiotensin-aldosterone-system. Renin, an enzyme released from the kidneys, converts the inactive plasma protein angiotensinogen into angiotensin I (Ang I). Then Ang I is converted to Ang II with angiotensin converting enzyme (ACE), see figure 2. Ang II in plasma then binds to AT-receptors.
ARBs are blocking the last part of the renin-angiotensin pathway and block the pathway more specifically than ACE inhibitors.
The AT1 receptor mediates Ang II to cause increased cardiac contractility, sodium reabsorption and vasoconstriction which all lead to increased blood pressure. By blocking AT1 receptors, ARBs lead to lower blood pressure.
An insurmountable inhibition of the AT1 receptor is achieved when the maximum response of Ang II cannot be restored in the presence of the ARB, no matter how high the concentration of Ang II is. The angiotensin receptor blockers can inhibit the receptor in a competitive surmountable, competitive insurmountable or noncompetitive fashion, depending upon the rate at which they dissociate from the receptor.
Read more about this topic: Discovery And Development Of Angiotensin Receptor Blockers
Famous quotes containing the words mechanism of, mechanism and/or action:
“A mechanism of some kind stands between us and almost every act of our lives.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 3, ch. 2 (1962)
“A mechanism of some kind stands between us and almost every act of our lives.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 3, ch. 2 (1962)
“Not rarely, and this is especially true of wives and mothers, the motive behind assuming a disproportionate share of work and responsibility is completely unselfish. We want to protect, to spare those of whom we are fond. We forget that, regardless of the motive, the results of such action are almost always destructive and unproductive.”
—Hortense Odlum (1892–?)