Nitric Oxide Signaling in Antidepressant Activity

Depression is a multifactorial disorder in which classical monoamine theories have gradually expanded to encompass modulatory roles for gaseous neurotransmitters. Nitric oxide (NO) has emerged as a pivotal regulator of synaptic plasticity, neurogenesis and cerebral blood flow, all of which are impaired in depressive states. Endogenously produced by nitric oxide synthase (NOS) enzymes from the substrate L-arginine, NO diffuses to activate soluble guanylate cyclase, elevating cyclic guanosine monophosphate (cGMP) levels and triggering downstream protein kinases. These cascades interact with glutamatergic NMDA receptors and monoaminergic pathways to influence neuronal excitability, dendritic remodelling and gene transcription. Preclinical models demonstrate that modulation of the L-arginine–NO–cGMP axis can both reproduce and reverse behaviours analogous to despair. Clinically, adjunctive strategies that inhibit excessive NO production or harness NO donors in a controlled fashion are under investigation to enhance response to established antidepressants. The global significance of this research lies in its potential to deliver faster onset of effect, greater efficacy in treatment-resistant cases and novel targets for pharmacotherapy.

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Nitric Oxide Signaling in Antidepressant Activity publication trend

The graph below shows the total number of articles in nitric oxide signaling in antidepressant activity across all publications each year (not limited to Nature Index journals).

Technical terms

Nitric oxide synthase (NOS): Enzyme family that converts L-arginine to nitric oxide and citrulline, comprising neuronal (nNOS), endothelial (eNOS) and inducible (iNOS) isoforms.

L-arginine–NO–cGMP pathway: Signalling cascade in which NO activates guanylate cyclase to synthesise cyclic guanosine monophosphate, a second messenger regulating protein kinases and ion channels.

NMDA receptor: N-methyl-D-aspartate subtype of glutamate receptor whose activation permits calcium influx and drives synaptic plasticity.

Monoaminergic system: Neural circuits that utilise serotonin, dopamine or noradrenaline to regulate mood, arousal and cognition, often targeted by conventional antidepressants.

References

1. Antidepressant Potentials of Components from Trichilia monadelpha (Thonn.) J.J. de Wilde in Murine Models. Evidence-based Complementary and Alternative Medicine (2018).
2. Monoaminergic and L-arginine-no-cGMP pathways mediate the antidepressant–like action of alkaloids from the stem bark of Trichilia monadelpha. Scientific African (2020).
3. NMDA receptors and L-arginine/nitric oxide/cyclic guanosine monophosphate pathway contribute to the antidepressant-like effect of Yueju pill in mice. Bioscience Reports (2019).
4. Potential strategies to optimize the efficacy of antidepressants: Beyond the monoamine theory. Electronic Journal of General Medicine (2023).