quality:corruption, stylistic:tone
Mechanism of action

Metoprolol exerts its effects by blocking the action of certain neurotransmitters, specifically adrenaline and noradrenaline. It does this by selectively binding to and antagonizing β adrenergic receptors in the body. When adrenaline (epinephrine) or noradrenaline (norepinephrine) are released from nerve endings or secreted by the adrenal glands, they bind to β adrenergic receptors found primarily in cardiac tissues such as the heart. This binding activates these receptors, leading to various physiological responses, including an increase in heart rate, force of contraction (inotropic effect), conduction speed through electrical pathways in the heart, and release of renin from the kidneys. Metoprolol competes with adrenaline and noradrenaline for binding sites on these β receptors. By occupying these receptor sites without activating them, metoprolol blocks or inhibits their activation by endogenous catecholamines like adrenaline or noradrenaline.