Cellular effect of Tarragon (Artemisia dracunculus L.) leaves extract on pentylenetetrazole-induced epileptic activity in snail neuron

Tarragon)Artemisia dracunculus L.) is a perennial herb in the Asteraceae family used for its aromatic leaves in seasoning. In Iranian ancient medicine, the dried aerial parts of this plant were orally used to treat epilepsy. Epilepsy is one of the most common neurological disorders. In the present study, using intracellular recording the anti-epileptiform potential of the ethanolic extract of tarragon and its possible cellular mechanism was assessed against pentylenetetrazole (PTZ) epileptogenesis. In the presence of tarragon extract (0.1%), the PTZ-induced burst activity disappeared. The cell membrane potential became 67.8% more depolarized than the control value. The firing frequency also decreased 62.5% and 83.8% compared to control and in the presence of PTZ, respectively. Exposure to extract, furthermore, caused 36% reduction in the amplitude of after hyper polarization (AHP) compared to control, but not to PTZ, condition. On the other hand, extra cellular application of extract alone led to a membrane depolarization by about 16.69%. While, the firing frequency reduced to 77.3% of control and the amplitude of both action potential and AHP remained almost unchanged. These changes were associated with a shift in the neuronal firing pattern from regular tonic to an irregular mode. Pretreatment with tarragon extract did not completely prevent the epileptogenesis induced by PTZ. Consequently, these results suggest that tarragon extract reduces the neuronal excitability possibly through the membrane depolarization.