Repeated electroconvulsive stimulation impairs long-term depression in the neostriatum.
BACKGROUND
Increasing and consistent findings of structural and functional abnormalities in patients with mood disorders demonstrate a clear involvement of the neostriatum. Therefore, the beneficial effect of electroconvulsive stimulation (ECS) treatment of acute state of mood disorder may relate to changes in striatal synaptic plasticity.


METHODS
We studied the effect of ECS treatment on the reported long-term depression (LTD) of synaptic excitatory afferents to striatal medium spiny neurons. Stimulation of the white matter between the cortex and the striatum elicited excitatory postsynaptic potentials (EPSPs) in medium spiny neurons in rat corticostriatal slices while recording using the whole-cell patch-clamp technique.


RESULTS
The EPSPs evoked in striatal neurons undergo LTD with repeated stimulation trains, and LTD of this pathway is impaired in rats after ECS treatment for 1 week, similar to what is reported in chronic lithium treatment. Electroconvulsive stimulation did not affect intrinsic membrane properties or the occurrence of spontaneous EPSCs. Dose-dependent inhibition of the EPSPs by a nonselective agonist of metabotropic glutamate receptor did not change in rats after ECS treatment.


CONCLUSIONS
Our data suggest that the effectiveness of electroconvulsive therapy in mood disorders may be a consequence of LTD impairment of excitatory cortical afferents to striatal projecting neurons.
De Murtas
Marco
M
Clinica Psichiatrica II Universitá di Roma la Sapienza (MDM, RT, PG), Rome, Italy.
Tatarelli
Roberto
R
Girardi
Paolo
P
Vicini
Stefano
S
D000818:Animals; D004565:Electroconvulsive Therapy; D004830:Epilepsy, Tonic-Clonic / Q000378:metabolism* / Q000628:therapy*; D019706:Excitatory Postsynaptic Potentials; D036881:Long-Term Synaptic Depression / Q000502:physiology; D017072:Neostriatum / Q000166:cytology / Q000378:metabolism*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism
D018094:Receptors, Metabotropic Glutamate