Summary: Two recent studies indicate that ezogabine, a drug previously approved for epilepsy, may relieve depressive symptoms by acting on potassium channels in the brain. The research shows ezogabine can normalize activity in reward-related regions—most notably the ventral tegmental area (VTA)—and reduce abnormal communication between reward circuits and brain regions linked to negative thinking, suggesting potassium channel openers could become a new biology-based treatment approach for depression and anhedonia.
Ezogabine decreased excessive connectivity between reward centers and areas associated with internal, negative thought patterns such as the posterior cingulate cortex. Together, these findings point to KCNQ channel openers as a promising strategy to directly target neural circuits involved in motivation, pleasure, and rumination in major depressive disorder (MDD).
Key Facts:
- New mechanism: Ezogabine modulates KCNQ (Kv7) voltage-gated potassium channels to influence neural excitability.
- Reward circuitry: The drug appears to reduce hyperactivity in dopamine-related regions, including the VTA, which are implicated in motivation and pleasure.
- Cognitive shift: Treatment with ezogabine lowers connectivity between reward regions and networks tied to negative thought, which correlates with clinical improvement.
Source: Mount Sinai Hospital
A mechanism involving potassium channels that regulate neuronal activity could offer a fundamentally different route to treating depressive symptoms in adults with major depressive disorder, according to two complementary papers from researchers at the Icahn School of Medicine at Mount Sinai.
Published recently in Biological Psychiatry and Molecular Psychiatry, these studies examine how ezogabine—a KCNQ channel opener—affects human brain function and connectivity to improve symptoms of depression, especially anhedonia (the reduced ability to experience pleasure).
“Depression is a devastating public health problem, and our understanding of the specific brain changes that cause the illness remains limited,” says James Murrough, MD, PhD, Director of the Depression and Anxiety Center for Discovery and Treatment at Mount Sinai and senior author on both studies. “Our work represents an important step toward identifying how targeting the KCNQ channel complex might lead to new treatment options.”
Ezogabine was approved by the U.S. Food and Drug Administration in 2011 as an anticonvulsant for partial-onset seizures in adults. Preclinical work at the Friedman Brain Institute suggested that enhancing KCNQ channel function could reduce aberrant activity of VTA dopamine neurons and produce antidepressant-like effects in animal models.
Building on that translational foundation, Murrough and colleagues were the first to test ezogabine’s effects in people with depression. An earlier randomized clinical trial reported in 2021 in the American Journal of Psychiatry found that ezogabine produced greater reductions in depressive symptoms and anhedonia than placebo. The two new papers present detailed analyses of the functional brain imaging collected during that trial, revealing potential neural mechanisms underlying clinical benefit.
The Molecular Psychiatry paper focused on VTA function during a monetary anticipation task measured with functional magnetic resonance imaging (fMRI). The investigators found that ezogabine significantly reduced task-related VTA activation over the course of treatment compared with placebo, consistent with the hypothesis that KCNQ channel openers can normalize VTA hyperactivity seen in depressed individuals with marked anhedonia.
“Up to half of people with depression do not respond to first-line treatments, which may reflect a shortage of therapies that directly target the neurobiology of symptoms like anhedonia,” says Laurel S. Morris, PhD, Adjunct Professor of Psychiatry at the Icahn School of Medicine and first author on the Molecular Psychiatry article. “By modulating VTA activity and its connectivity, ezogabine could improve outcomes for patients who struggle with motivation and pleasure.”
The complementary Biological Psychiatry paper examined resting-state functional connectivity (RSFC) of key striatal reward regions—such as the ventral caudate and nucleus accumbens—and their interactions with broader brain networks. Compared with placebo, ezogabine reduced connectivity between these striatal seeds and mid/posterior cingulate regions, including the posterior cingulate cortex (PCC) and precuneus. Importantly, decreases in this striatal–cingulate connectivity correlated with improvements in depressive symptoms and anhedonia scores.
Together, the two studies suggest a coherent mechanism: KCNQ channel openers can both quell excessive VTA activation and weaken the coupling between reward circuits and brain regions involved in internally focused negative thought, such as rumination. This dual effect—modulating local reward-related activity and altering large-scale network connectivity—may underlie the observed clinical improvements.
“These findings indicate that drugs targeting KCNQ channels may exert antidepressant effects by reducing interactions between reward centers and networks linked to negative emotion and self-focused thought,” Dr. Murrough explains. He notes that these results will need confirmation in larger, more definitive clinical trials.
Dr. Murrough is a named inventor on a pending patent application related to the use of ezogabine and other KCNQ channel openers for depression and related disorders.
About this psychopharmacology and depression research news
Author: Elizabeth Dowling
Source: Mount Sinai Hospital
Contact: Elizabeth Dowling – Mount Sinai Hospital
Image: The image is credited to Neuroscience News
Original Research: Closed access. “Effects of KCNQ potassium channel modulation on ventral tegmental area activity and connectivity in individuals with depression and anhedonia” by James Murrough et al., Molecular Psychiatry.
Closed access. “Effects of the KCNQ (Kv7) Channel Opener Ezogabine on Resting-State Functional Connectivity of Striatal Brain Reward Regions, Depression, and Anhedonia in Major Depressive Disorder: Results From a Randomized Controlled Trial” by James Murrough et al., Biological Psychiatry.
Abstract — Molecular Psychiatry paper
Effects of KCNQ potassium channel modulation on ventral tegmental area activity and connectivity in individuals with depression and anhedonia
Many individuals with major depressive disorder fail to respond adequately to standard treatments, in part because available therapies do not always target the specific neural mechanisms that sustain key symptoms like anhedonia. Translational research has proposed that aberrant VTA dopamine neuron activity contributes to these symptoms and that modulation of KCNQ channels offers a potential corrective mechanism.
In this randomized study, adults with MDD and elevated anhedonia received five weeks of ezogabine (up to 900 mg/day) or placebo. Participants completed fMRI during a monetary anticipation task and resting-state scans before and after treatment. Analyses showed a significant drug-by-time interaction: VTA activation during anticipation decreased from pre- to post-treatment with ezogabine compared with placebo. Baseline mesocortical connectivity (VTA to ventromedial prefrontal cortex) was higher in depressed participants relative to healthy controls and correlated with VTA hyperactivity; this mesocortical connectivity also decreased following ezogabine treatment. These results align with preclinical data implicating VTA hyperactivity in depression and suggest KCNQ channel openers can normalize that hyperactivity in people with depression and anhedonia.
Abstract — Biological Psychiatry paper
Effects of the KCNQ (Kv7) Channel Opener Ezogabine on Resting-State Functional Connectivity of Striatal Brain Reward Regions, Depression, and Anhedonia in Major Depressive Disorder: Results From a Randomized Controlled Trial
Background
Major depressive disorder is a global cause of disability, and treatment responses are often incomplete. Targeting specific neurobiological features of depression—such as disrupted reward processing—may improve therapeutic outcomes. This study evaluated whether ezogabine, a KCNQ channel opener, alters resting-state connectivity of reward circuitry and relieves depressive symptoms including anhedonia.
Methods
A double-blind, randomized, placebo-controlled trial enrolled adults with MDD (ages 18–65) and elevated anhedonia. Participants received daily ezogabine (n=19) or placebo (n=21) for five weeks. Functional MRI assessed RSFC of striatal reward regions (ventral caudate, nucleus accumbens) at baseline and posttreatment. Clinical outcomes were measured with validated scales including the Snaith-Hamilton Pleasure Scale (SHAPS) and the Montgomery–Åsberg Depression Rating Scale (MADRS).
Results
Treatment with ezogabine significantly reduced RSFC between striatal reward seeds and the posterior cingulate cortex/precuneus compared with placebo, and these reductions were associated with decreases in depression severity. Improvements in anhedonia and depressive symptoms correlated with decreased connectivity between reward regions and mid/posterior cingulate areas (midcingulate cortex, PCC, precuneus).
Conclusions
The data indicate ezogabine’s antidepressant and anti-anhedonic effects may be mediated by modulation of striatal–mid/posterior cingulate connectivity. These findings support further investigation of KCNQ-targeted therapies in larger clinical trials to confirm efficacy and clarify mechanisms in MDD.