Z. Dennison et al., PERSISTENCE OF KINDLING - EFFECT OF PARTIAL KINDLING, RETENTION INTERVAL, KINDLING SITE, AND STIMULATION PARAMETERS, Epilepsy research, 21(3), 1995, pp. 171-182
The kindling effect is generally thought to be highly persistent and p
ossibly permanent, but little direct evidence is available to support
this idea. Retention of amygdala kindling was examined after a 12-wk i
nterval in groups of rats that had been electrically kindled to differ
ent seizure stages (stages 1, 3, or 5), or kindled by high intensity o
r low frequency (3 pulses per second) stimulation, or fully kindled an
d allowed a rest of 1-24 wk. The retention of hippocampal kindling aft
er a 12-wk interval was also examined. Rekindling after a 12-wk rest i
n the groups initially kindled to different seizure stages indicated t
hat although there was evidence of erosion of the kindling effect in a
ll groups, there were savings in all groups. There was also evidence o
f greater erosion in the afterdischarge response than in the convulsiv
e response to the first stimulation after the interval. Although there
was evidence of erosion of kindling during the 1-24-wk intervals, the
re was evidence of savings in all groups, none of which required more
than a mean of 2.2 afterdischarges to rekindle to stage 5. Seizures ki
ndled in the hippocampus were retained as well as those kindled in the
amygdala, and seizures kindled using low frequency stimulation were r
etained as well as those kindled using conventional 60 pulses per seco
nd stimulation. We conclude that the effects of kindling the amygdala
and hippocampus are highly persistent, and that the effects of kindlin
g with low frequency stimulation are as persistent as kindling with co
nventional stimulation.