Final answer:
Beta blockers work by inhibiting the beta-1 receptors in the heart, slowing down the heart rate, and are used to treat cardiovascular conditions like hypertension. Overuse can cause bradycardia or cardiac arrest. Potassium channel blockers, on the other hand, affect repolarization in the heart's action potential to manage arrhythmias.
Step-by-step explanation:
Beta blockers are a class of medications used to treat cardiovascular diseases like hypertension and cardiac dysrhythmias. One way they work is by blocking the effects of the neurotransmitter norepinephrine (NE) at the beta-1 receptor in the heart, which can slow down the heart rate (HR). Metoprolol, for example, is selective for the beta-1 receptor and is commonly used for this purpose. Overprescription can result in side effects such as bradycardia or even cardiac arrest. In contrast, potassium channel blockers, like amiodarone and procainamide, target voltage-gated K+ channels during the action potential, specifically during repolarization, to treat arrhythmias.
Negative inotropic agents, including several beta blockers and calcium channel blockers, decrease the strength of heart contraction and stroke volume (SV), impacting treatable conditions like angina pectoris. The cardioinhibitor centers can also reduce cardiac function by stimulating the vagus nerve, which releases acetylcholine to decrease HR and SV.