serotoninnorepinephrine

Serotonin-norepinephrine refers to the two monoamine neurotransmitters, serotonin (5-HT) and norepinephrine (noradrenaline, NE), and the ways they interact within brain networks. Serotonin is produced primarily in the dorsal raphe nucleus, while norepinephrine arises mainly from the locus coeruleus; both systems project widely to cortical and subcortical regions. Together, these neurotransmitters regulate mood, arousal, attention, pain perception, sleep-wake cycles, appetite, and cognitive function.

In physiological terms, serotonin and norepinephrine modulate neural activity through multiple receptor subtypes and circuits. Serotonin is closely linked to mood stabilization, social behavior, and impulse control, whereas norepinephrine modulates vigilance, environmental monitoring, and the stress response. The two systems interact in ways that can amplify or dampen signals, and dysregulation of their balance is implicated in mood and anxiety disorders, chronic pain, and sleep disturbances.

Pharmacologically, many antidepressants target these pathways. Serotonin-norepinephrine reuptake inhibitors (SNRIs), such as venlafaxine, duloxetine, and levomilnacipran, increase extracellular levels of both serotonin and norepinephrine and are used for major depressive disorder, generalized anxiety disorder, panic disorder, and certain chronic pain conditions. Other antidepressants may affect one system more than the other (for example, SSRIs mainly affect serotonin), and some older agents influence both systems as part of a broader pharmacologic profile. Side effects can include hypertension, tachycardia, insomnia, and gastrointestinal symptoms, with withdrawal symptoms possible on discontinuation.

Research on serotonin-norepinephrine explores how these systems coordinate to regulate mood, cognition, and pain, aiming to optimize treatment strategies for related conditions.