Abstracts

RATIONALE: The mechanism of action of electroconvulsive therapy (ECT) is unknown, however ECT[ssquote]s anti-convulsant effect have been proposed to play a roll. Seizure threshold increases during the typical course of ECT and animal studies have suggested an anticonvulsant property of the cerebrospinal fluid (CSF) following electroconvulsive shock. The present study investigated whether or not this property exists in human CSF following one ECT treatment, 9 ECT treatments or a spontaneous first seizure.
METHODS: Male Sprague-Dawley rats were placed in a sealed 12.6 liter plastic container. Flurothyl was infused into the container on to a piece of filter paper at the rate of 0.1ml/minute using an infusion pump. A timer was begun at the start of flurothyl infusion and the time was recorded at two points: 1.) when the rat started to have myoclonic jerks; and 2.) when there was a generalized tonic seizure. The infusion was then immediately stopped and the animal removed from the container. This process was repeated once per day for up to four consecutive days. There were 5 experimental groups:
Group 1 (n=5) artificial CSF (aCSF) intraventricular injected.
Group 2 (n=9) control human CSF intraventricular injected.
Group 3 (n=9) post 9 sessions ECT human CSF intraventricular injected
Group 4 (n=4) post 1 session ECT human CSF intraventricular injected
Group 5 (n=5) post first seizure human CSF intraventricular injected
Data was analyzed using ANOVA with repeated measures and t-tests.
RESULTS: Decrease in seizure threshold over time (4 days) was highly significant (p[lt]0.001) for all groups, for both myoclonic and tonic seizures, demonstrating a kindling effect.
For myoclonic seizures, latencies to seizure onset were not significantly different than control in any of the four treatment groups verses control.
For the tonic seizures, the first seizure group (F=15.19; p=0.001) was significantly different than control CSF group over time (4 days). Additionally, on day 3 the first seizure group was significantly different than control CSF (p=0.024) when measuring the onset of tonic seizure.
There was no significant [dsquote]group x time[dsquote] interaction compared to control CSF for any of the 4 groups verses control for either myoclonic or tonic seizures.
(figures 1 & 2)
CONCLUSIONS: The results of this first study ever to assess human post-ictal CSF for an anticonvulsive property suggest that:
1.) There is no anticonvulsant property in the CSF of humans following ECT.
2.) Human CSF following a first generalized seizure may have a neuroprotective property which prevents kindling.[figure1][figure2]
[Supported in part by the National Institutes of Mental Health (MH57980).]