Positive inotropes often work by increasing the intracellular concentration of calcium ions, which enhances the heart's ability to contract. For example, dobutamine stimulates beta-1 adrenergic receptors, leading to increased cardiac output. In contrast, negative inotropes like beta-blockers inhibit the effects of adrenaline and other stress hormones, reducing heart contractility. This mechanism is crucial in conditions like hypertension and arrhythmias.
