The role of the substantia nigra pars reticulata anterior in amygdala-kindled seizures.

BACKGROUND

It has been reported that the substantia nigra pars reticulata (SNr) is of regional differences and involved in the initiation, generalization, and cessation of seizures. However, neuropharmacological investigations into the role of the SNr anterior (SNr) in temporal lobe epilepsy (TLE) have been inconsistent, suggesting that electrophysiological investigations are needed to elucidate the role of the SNr in TLE.

METHODS

Local field potentials (LFPs) and single-unit activities were simultaneously obtained from the basolateral amygdala (BLA) and the SNr in amygdala-kindled mice. The electrophysiological characteristics of the neuronal activities in the BLA and SNr were investigated. Directionality index was used to measure information flow between LFPs in the two areas during kindled seizures. The effects of electrical lesion of the SNr on the kindled seizures were analyzed in fully-kindled mice.

RESULTS

The information flow was predominantly from the SNr to the BLA during the clonic-like periods of stage 5 seizures, but this phenomenon was not found during other kindled seizures. In fully-kindled mice, SNr lesions facilitated the kindled seizures. After lesions were inflicted, the afterdischarge durations and clonic-like periods of stage 5 seizures increased significantly.

CONCLUSION

The electrophysiological and lesion results show that the SNr may play an anti-convulsant role in amygdala-kindled seizures.