Which neurotransmitter is responsible for shortening the time
it takes for cardiac cells to repolarize?
dopamine
epinephrine
norepinephrine

Epinephrine, also known as adrenaline, plays a crucial role in the fight-or-flight response and is responsible for shortening cardiac repolarization time. It binds to beta-adrenergic receptors in the heart, increasing heart rate and contractility, which also affects the duration of the repolarization phase of cardiac action potentials.

Norepinephrine, another important neurotransmitter, also impacts cardiac function. It primarily influences heart rate by acting on similar receptors, but its effects are generally more prolonged compared to epinephrine. In a high-stress situation, both neurotransmitters work in concert, ensuring that your heart can respond quickly to perceived threats!