Noradrenaline acts as a neurotransmitter between sympathetic postganglionic nerves and the organs they innervate. When an action potential reaches the nerve terminal, noradrenaline is released into the synaptic cleft and binds to alpha adrenoreceptors on nearby cells. This causes vasoconstriction and increases both systolic and diastolic blood pressure, raising mean arterial pressure. Noradrenaline interacts with various other drugs and medications and can cause side effects like anxiety, dizziness, and tremors. It should be used cautiously in patients with certain medical conditions.