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Activity of S-adenosylmethionine decarboxylase, a key regulatory enzyme in polyamine biosynthesis, is increased in
L D Morrison1, A L Sherwin, L Carmant
1Human Neurochemical Pathology Laboratory, Clarke Institute of Psychiatry, Toronto, Ontario.
Objective:
We measured the activity of S-adenosylmethionine decarboxylase, a key regulatory enzyme of polyamine biosynthesis, in the temporal cortex of patients with epilepsy.
Design:
Cortical surgical specimens were obtained following anterior temporal lobe resection for intractable epilepsy. Enzyme activity was compared in nonepileptogenic (n = 16) and epileptogenic (spontaneously discharging; n = 19) regions.
Results:
Mean enzyme activity was increased by 44% in samples from epileptogenic cortex compared with samples from nonepileptic regions. The S-adenosylmethionine decarboxylase activity in regions of focal epileptogenic discharges was also increased in five patients compared with paired samples from the nonepileptogenic portion of the same gyrus (+55%).
Conclusions:
Elevated activity of S-adenosylmethionine decarboxylase in regions of active epileptogenic cortical discharges suggests that a disturbance of the polyamine system may be involved in the maintenance of hypersynchronous discharges, perhaps through a modulatory action at the excitatory N-methyl-D-aspartate-preferring glutamate receptor.