Research indicates that neurotransmitter systems can influence not only mood and perception but also physiological responses. The most well-known neurotransmitters include dopamine, serotonin, and norepinephrine, each associated with distinct functions and implications for mental health. A unique characteristic of these neurotransmitters is their interaction with specific receptors, which can lead to different outcomes. For example, dopamine is often linked to reward pathways, while serotonin is associated with mood regulation. Considering these roles, which neurotransmitter is primarily involved in the modulation of arousal and alertness through its action on adrenergic receptors?