Alteration of NMDA receptor-mediated synaptic interactions in the lateral amygdala associated with seizure activity in a mouse model of chronic temporal lobe epilepsy.
OBJECTIVE
Because results from both animal models and human temporal lobe epilepsy (TLE) have pointed to synaptic network alterations in the amygdala, we have tested the hypothesis that glutamatergic transmission in the lateral amygdala (LA) is critically involved.


METHODS
Using the pilocarpine mouse model, LA slices were prepared ex vivo in the recurrent phase of TLE (Pilo group), and LA projection neurons (PNs) were recorded using patch-clamp techniques. Intrinsic and synaptic properties of LA PNs were analyzed and compared with those in age-matched saline-injected controls.


RESULTS
Only mild changes were observed in intrinsic properties of LA PNs, whereas both spontaneous excitatory postsynaptic currents (sEPSCs) and miniature EPSCs (mEPSCs) were significantly increased in Pilo as compared to saline controls. This difference was sensitive to AP5, but persisted during action of NBQX, indicating mediation by N-methyl-d-aspartate (NMDA) receptors. Moreover, these changes were associated with an increase in frequency but not amplitude of mEPSCs, indicative of a contribution of presynaptic mechanisms.


CONCLUSIONS
In conclusion, dynamic changes seem to occur in glutamatergic transmission within the amygdala during TLE, to which a functional upregulation of presynaptic NMDA receptors in LA PNs makes a significant contribution.
Graebenitz
Stéphanie
S
Institute for Physiology I, Westfälische Wilhelms-Universität, Münster, Germany.
Lesting
Jörg
J
Sosulina
Ludmila
L
Seidenbecher
Thomas
T
Pape
Hans-Christian
HC
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D002908:Chronic Disease; D004195:Disease Models, Animal; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006801:Humans; D051379:Mice; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D010862:Pilocarpine; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D012640:Seizures / Q000139:chemically induced / Q000503:physiopathology; D009435:Synaptic Transmission / Q000502:physiology
D016194:Receptors, N-Methyl-D-Aspartate; D010862:Pilocarpine