Bisoprolol is a drug belonging to the group of beta blockers, a class of medicines used primarily in cardiovascular diseases. More specifically, it is a selective type β1 adrenergic receptor blocker. Bisoprolol is cardioprotective because it selectively and competitively blocks catecholamine (adrenalin) stimulation of β1 adrenergic receptors (adrenoreceptors), which are mainly found in the heart muscle cells and heart conduction tissue (cardio specific) but also found in juxtaglomerular cells in the kidney. Normally adrenalin and noradrenalin stimulation of the β1 adrenoreceptor activates a signalling cascade (Gs protein and cAMP) which ultimately lead to increased contractility and increased heart rate of the heart muscle and heart pacemaker respectively. Bisoprolol competitively blocks the activation of this cascade and therefore decreases the adrenergic tone/stimulation of the heart muscle and pacemaker cells.
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