Epileptogenesis induced by alternate-site kindling in bilateral hippocampi.
OBJECTIVE
Alternate-site kindling (AK), which has been known to induce so-called kindling antagonism, was performed in the bilateral hippocampi to reveal neural mechanisms underlying hippocampal kindling.


METHODS
Ten adult rabbits were used. Daily kindling stimulation consisted of a 1- s train of 50 pulses (pulse duration, 1 ms) of 80 to 200 microA (base-to-peak), which was higher than the afterdischarge (AD) threshold. The concurrent alternating stimulations were delivered to the right and left hippocampus once every 24 h.


RESULTS
All animals developed a stage 5 convulsion with a mean of 28.1 +/- 3.3 (mean +/- SEM) stimulations. The right and left hippocampus received 14.8 +/- 1.7 and 14.6 +/- 1.6 stimulations, respectively. Behavioral stages induced by stimulation of the right or left hippocampus evolved to generalized seizures along a similar course. Kindling antagonism was not observed. The two sides showed similar increases in AD duration, and similar chronologic changes in interictal discharge (IID) frequency. Simple A-type IID and complex types of IID appeared at higher rates, whereas simple B-type IID remained at a relatively low level.


CONCLUSIONS
The present AK procedure did not induce kindling antagonism, but it induced progression of kindling manifestations. The origin of simple B-type IID is known to be in the contralateral side, and its intracellular counterpart corresponds to a sequence of small depolarization followed by large hyperpolarization, suggesting that plastic changes in the feed-forward inhibitory system play an important role in hippocampal kindling.
Matsuda
Yoshiki
Y
Department of Neuropsychiatry, Saitama Medical School, Saitama, Japan.
Yano
Michiko
M
Kitayama
Masaomi
M
Kogure
Shinichi
S
Yamauchi
Toshio
T
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D004195:Disease Models, Animal; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000209:etiology* / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology* / Q000503:physiopathology; D007696:Kindling, Neurologic / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D011817:Rabbits; D012640:Seizures / Q000209:etiology / Q000503:physiopathology