Serotonin 2C receptor antagonists induce fast-onset antidepressant effects

Area of Science:

• Neuroscience
• Pharmacology
• Molecular Biology

Background:

• Current antidepressants, like SSRIs, require weeks for therapeutic effects.
• The need for faster-acting antidepressant treatments is critical.

Purpose of the Study:

• To investigate the potential of selective serotonin 2C (5-HT2C) antagonists as fast-onset antidepressants.
• To elucidate the underlying molecular and neural mechanisms of 5-HT2C antagonist action.

Main Methods:

• Administered 5-HT2C antagonists and SSRIs (citalopram) to mice in behavioral models (cFST, CMS, olfactory bulbectomy).
• Assessed molecular markers (CREB, BDNF, mTOR, eEF2) in the medial prefrontal cortex (mPFC).
• Utilized local infusions and receptor antagonists to probe neural pathways.

Main Results:

• 5-HT2C antagonists produced antidepressant behavioral effects and molecular changes (CREB, BDNF activation) within 5 days, unlike SSRIs.
• 5-HT2C antagonists enhanced mesocortical dopaminergic signaling, activating mTOR and eEF2.
• These antagonists reversed stress-induced neuronal atrophy in the mPFC.

Conclusions:

• 5-HT2C antagonists represent promising candidates for fast-onset antidepressant therapies.
• Their mechanism involves enhancing mesocortical dopaminergic signaling, distinct from SSRI onset pathways.