Electroconvulsive Seizures Regulate Gene Expression of Distinct Neurotrophic Signaling Pathways

TLDR

ECT is the preferred treatment for drug‑resistant depression, yet its mechanism remains unclear; neurogenesis and plasticity pathways involving BDNF, glutamate, and cAMP‑PKA may mediate its antidepressant effects. The study seeks to identify genes up‑regulated only after chronic electroconvulsive seizures—such as neuropeptide Y and thyrotropin‑releasing hormone—to guide drug selection and replicate ECT’s rapid efficacy. Gene transcription was profiled in rat frontal cortex and hippocampus following sham, 1, or 10 electroconvulsive seizures, a model of ECT. ECS altered expression of 120 genes, with the hippocampus showing over three times more changes than cortex and many persisting chronically; 77 genes were novel, 39 validated by qRT‑PCR, and 19 highly significant low‑fold changes, with affected genes distributed across BDNF‑MAPK‑cAMP‑CREB, arachidonic acid, immediate‑early, neurogenesis, and exercise‑response pathways.

Abstract

Electroconvulsive therapy (ECT) remains the treatment of choice for drug-resistant patients with depressive disorders, yet the mechanism for its efficacy remains unknown. Gene transcription changes were measured in the frontal cortex and hippocampus of rats subjected to sham seizures or to 1 or 10 electroconvulsive seizures (ECS), a model of ECT. Among the 3500–4400 RNA sequences detected in each sample, ECS increased by 1.5- to 11-fold or decreased by at least 34% the expression of 120 unique genes. The hippocampus produced more than three times the number of gene changes seen in the cortex, and many hippocampal gene changes persisted with chronic ECS, unlike in the cortex. Among the 120 genes, 77 have not been reported in previous studies of ECS or seizure responses, and 39 were confirmed among 59 studied by quantitative real time PCR. Another 19 genes, 10 previously unreported, changed by <1.5-fold but with very high significance. Multiple genes were identified within distinct pathways, including the BDNF–MAP kinase–cAMP–cAMP response element-binding protein pathway (15 genes), the arachidonic acid pathway (5 genes), and more than 10 genes in each of the immediate-early gene, neurogenesis, and exercise response gene groups. Neurogenesis, neurite outgrowth, and neuronal plasticity associated with BDNF, glutamate, and cAMP–protein kinase A signaling pathways may mediate the antidepressant effects of ECT in humans. These genes, and others that increase only with chronic ECS such as neuropeptide Y and thyrotropin-releasing hormone, may provide novel ways to select drugs for the treatment of depression and mimic the rapid effectiveness of ECT.