What does eplerenone specifically bind to?

Eplerenone is a selective aldosterone receptor antagonist (SARA) that specifically binds to aldosterone receptors. By doing so, it blocks the action of aldosterone, a hormone that regulates sodium and potassium levels in the body. Aldosterone binds to its receptors in the kidneys, leading to sodium reabsorption and potassium secretion; therefore, by inhibiting this process, eplerenone is effective in treating conditions such as hypertension and heart failure.

In the context of the other answer options, renin receptors are involved in the regulation of blood pressure and fluid balance through the renin-angiotensin-aldosterone system but are not the target of eplerenone. Sodium receptors are not a recognized specific receptor type in this context, and while they relate to the actions of aldosterone, they do not represent the direct binding target of eplerenone. Angiotensin receptors are involved in the effects of angiotensin II, another important hormone in blood pressure regulation, but eplerenone does not bind to these receptors either. The specificity of eplerenone for aldosterone receptors is what results in its pharmacological effects.