Quenching revisited: low level direct current inhibits amygdala-kindled seizures.
We have reported that low frequency stimulation (1 Hz for 15 min), applied after kindling stimulation of the amygdala, inhibited the development and expression of amygdala-kindled seizures, an effect we termed quenching. Subsequently, we discovered that this effect could only be achieved when certain stimulators were used that also emitted a low-level direct current (DC). The studies reported here indicate that DC, applied once daily for 15 min at intensities of 5-15 microA, produced an intensity-related attenuation of kindling development and an increase in the afterdischarge threshold. This effect persisted in some animals for at least 1 month after discontinuation of the DC. In fully kindled animals, a robust increase in seizure threshold and persistent seizure inhibition were also observed using 10 microA of DC administered for 14 days. These results clarify and extend our original findings of a quenching effect; however, the mechanisms by which low level DC induces quenching require further elucidation.
Weiss
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SR
Biological Psychiatry Branch, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
Eidsath
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A
Li
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Heynen
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Post
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RM
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004599:Electric Stimulation Therapy / Q000379:methods; D007696:Kindling, Neurologic / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000517:prevention & control*