Article

Inhibition of calcium/calmodulin kinase II alpha subunit expression results in epileptiform activity in cultured hippocampal neurons

Department of Neurology, Virginia Commonwealth University, Medical College of Virginia, Richmond, VA 23298, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 06/2000; 97(10):5604-9. DOI: 10.1073/pnas.080071697
Source: PubMed

ABSTRACT Several models that develop epileptiform discharges and epilepsy have been associated with a decrease in the activity of calmodulin-dependent kinase II. However, none of these studies has demonstrated a causal relationship between a decrease in calcium/calmodulin kinase II activity and the development of seizure activity. The present study was conducted to determine the effect of directly reducing calcium/calmodulin-dependent kinase activity on the development of epileptiform discharges in hippocampal neurons in culture. Complimentary oligonucleotides specific for the alpha subunit of the calcium/calmodulin kinase were used to decrease the expression of the enzyme. Reduction in kinase expression was confirmed by Western analysis, immunocytochemistry, and exogenous substrate phosphorylation. Increased neuronal excitability and frank epileptiform discharges were observed after a significant reduction in calmodulin kinase II expression. The epileptiform activity was a synchronous event and was not caused by random neuronal firing. Furthermore, the magnitude of decreased kinase expression correlated with the increased neuronal excitability. The data suggest that decreased calmodulin kinase II activity may play a role in epileptogenesis and the long-term plasticity changes associated with the development of pathological seizure activity and epilepsy.

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    • "Consistent with a role for reduced CaMKII activity in the etiology of seizures, mice lacking CaMKIIa exhibit epileptiform activity in response to normally subconvulsive brain stimuli (Butler et al., 1995). What's more, in dissociated cultures of hippocampus or cerebral cortex, inhibition of CamKIIa expression (Churn et al., 2000b) or a generalized reduction in CaMKII activity (Ashpole et al., 2012) produced eplileptic-like activity. "
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