Pharmaco-genetic inhibition of pyramidal neurons retards hippocampal kindling-induced epileptogenesis

Abstract

Aims: Pharmaco-genetics emerges as a new promising approach for epileptic seizures. Whether it can modulate epileptogenesis is still unknown.

Methods: Here, parvalbumin neurons and pyramidal neurons of the seizure focus were transfected with engineered excitatory Gq-coupled human muscarinic receptor hM3Dq and engineered inhibitory Gi-coupled human muscarinic receptor hM4Di, respectively. And their therapeutic value in mouse hippocampal kindling-induced epileptogenesis was tested.

Results: Pharmaco-genetic activating parvalbumin neurons limitedly retarded the progression of behavioral seizure stage and afterdischarge duration (ADD) during epileptogenesis induced by kindling. Activating parvalbumin neurons delayed seizure development only in the early stage, but accelerated it in late stages. On the contrary, pharmaco-genetic inhibiting pyramidal neurons robustly retarded the progression of seizure stages and ADDs, which greatly delayed seizure development in both early and late stages. Although both pharmaco-genetic therapeutics efficiently alleviated the severity of acute kindling-induced seizures, pharmaco-genetic inhibiting pyramidal neurons were able to reverse the enhanced synaptic plasticity during epileptogenesis, compared with that of pharmaco-genetic activating parvalbumin neurons.

Conclusion: Our results demonstrated that pharmaco-genetic inhibiting pyramidal neurons retard hippocampal kindling-induced epileptogenesis and reverse the enhanced synaptic plasticity during epileptogenesis, compared with that of pharmaco-genetic activating parvalbumin neurons. It suggests that pharmaco-genetics targeting pyramidal neurons may be a promising treatment for epileptogenesis.

Keywords: epilepsy; parvalbumin neurons; pharmaco-genetics; pyramidal neurons; synaptic plasticity.