Plasticity at axon initial segment of hippocampal CA3 neurons in rat after status epilepticus induced by lithium-pilocarpine.
BACKGROUND
The axon initial segment (AIS) is a specialized membrane region in the axon of neurons wherein numerous specific voltage-gated sodium channels (VGSCs) are clustered and action potentials are initiated. The AIS is currently considered as a new plastic hotspot.


METHODS
We investigated the alterations in Nav1.6 (SCN8A) and its adapter protein ankyrin G in the AIS of the hippocampal cornu ammonis 3 (CA3) pyramidal cells of rat after status epilepticus induced by lithium-pilocarpine (PISE).


RESULTS
Nav1.6 and ankyrin G were colocalized in the AIS of hippocampal CA3 pyramidal neurons. Compared with the control group, the protein and mRNA expression of Nav1.6 increased within 24 h and 60 days after PISE. By contrast, ankyrin G protein expression decreased slightly within 24 h but increased within 60 days, whereas ankyrin G mRNA increased within 24 h and 60 days after PISE. However, the protein and mRNA expression levels of Nav1.6 and ankyrin G within 7 days after PISE did not differ significantly with those of the control.


CONCLUSIONS
Nav1.6 and ankyrin G may participate in the plastic changes in the AIS of hippocampus CA3 neurons after PISE and play potential roles in epileptogenesis by regulating neuronal excitability.
Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, 410008, China.
Li
L
Feng
Ai-Ping
AP
Li
Mei-Ping
MP
Wang
Dan-Ni
DN
Sun
Ye-Lan
YL
Wang
Li-Li
LL
Long
Bo
B
Xiao
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001369:Axons / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects* / Q000503:physiopathology; D018020:Lithium Compounds / Q000633:toxicity*; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects*; D010862:Pilocarpine / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013226:Status Epilepticus / Q000139:chemically induced / Q000503:physiopathology*
D018020:Lithium Compounds; D010862:Pilocarpine