Anticonvulsant effects of sevoflurane on amygdaloid kindling and bicuculline-induced seizures in cats: comparison with isoflurane and halothane.
OBJECTIVE
We compared the anticonvulsant effects of sevoflurane with those of isoflurane and halothane in amygdaloid kindling and bicuculline-induced seizures in cats.


METHODS
In a crossover design, the effects of 70% nitrous oxide, and 0.3, 0.6, and 1.5 minimum alveolar concentration (MAC) of volatile anesthetics were studied in five cats in which the amygdala was electrically stimulated at the current used for establishing the kindled state. The effects of 0.6 and 1.5 MAC of volatile anesthetics were studied in another five cats, in which 0.2 mg.kg(-1) of bicuculline was administered i.v..


RESULTS
In the amygdaloid kindling model, all four anesthetics decreased the duration of after-discharge (AD), the rise of multiunit activity in midbrain reticular formation (R-MUA), and the behavior scores compared with findings without anesthetics. Halothane, at 1.5 MAC, significantly decreased the number of cats showing AD ( P < 0.05). In the bicuculline-induced seizure model, all five cats showed repetitive spikes during 1.5 MAC of sevoflurane, whereas only two and three cats, respectively, showed the repetitive spikes during 1.5 MAC of isoflurane and halothane. All three volatile anesthetics decreased the rise of R-MUA, the duration of the repetitive spikes, and the behavior scores. The suppression of the rise in R-MUA and the behavior scores with 1.5 MAC of sevoflurane was significantly less than that with 1.5 MAC of isoflurane.


CONCLUSIONS
The anticonvulsant effects of sevoflurane were less potent than those of halothane in the amygdaloid kindling model and less potent than those of isoflurane in the bicuculline-induced seizure model.
Murao
Kohei
K
Department of Anesthesiology, Kansai Medical University, 10-15 Fumizono-cho Moriguchi, Osaka 570-8507, Japan.
Shingu
Koh
K
Miyamoto
Etsuko
E
Ikeda
Sakahiro
S
Nakao
Shin-ichi
S
Masuzawa
Munehiro
M
Yamada
Makiko
M