Abstract
Background
It is uncertain how electroconvulsive therapy (ECT)-induced generalized seizures exert their potent therapeutic effects on various neuropsychiatric disorders. Adenosine monophosphate-activated protein kinase (AMPK) plays a major role in maintaining metabolic homeostasis, and activates autophagic processes via unc-51-like kinase (ULK1). Evidence supports the involvement of autophagy system in the action mechanisms of antidepressants and antipsychotics. The effect of ECT on autophagy-related signaling requires further clarification.
Methods
The effect of electroconvulsive seizure (ECS) on autophagy, and its association with the AMPK signaling pathway, were investigated in the rat frontal cortex. ECS was provided once per day for 10 days (E10X), and compound C or 3-methyadenine was administered through an intracerebroventricular (i.c.v.) cannula. Molecular changes were analyzed with immunoblot, immunohistochemistry, and transmission electron microscopy (TEM) analyses.
Results
E10X increased p-Thr172-AMPKα immunoreactivity in rat frontal cortex neurons. E10X increased phosphorylation of upstream effectors of AMPK, such as LKB1, CaMKK, and TAK1, and of its substrates, ACC, HMGR, and GABABR2. E10X also increased p-Ser317-ULK1 immunoreactivity. At the same time, LC3-II and ATG5–ATG12 conjugate immunoreactivity increased, indicating activation of autophagy. An i.c.v injection of the AMPK inhibitor compound C attenuated the ECS-induced increase in ULK1 phosphorylation, as well as the protein levels of LC3-II and Atg5–Atg12 conjugate. TEM clearly showed an increased number of autophagosomes in the rat frontal cortex after E10X, which was reduced by i.c.v treatment with the autophagy inhibitor 3-methyadenine and compound C.
Conclusions
Repeated ECS treatments activated in vivo autophagy in the rat frontal cortex through the AMPK signaling pathway.
Effects of systemically administered ceruletide on dopamine metabolism in the rat frontal cortex: an in vivo microdialysis study
