Electrophysiological investigation of the cellular effect of anethole, the chief constitute of anise, on F1 neuronal excitability in garden snail

Introduction: Anethole is the main constituent of Pimpinella anisum L. (anise), a herbaceous annual plant which has several therapeutic effects. In the folk medicine, anise is employed as an antiepileptic drug. Specifically, this study was focused on the cellular effect of anethole, an aromatic compound in essential oils from anise and camphor. Anethole has various physiological effects on the cardiovascular system and smooth and skeletal muscles. However, despite these persistent effects, there is little information available about the actions of anethole on nerve cells. Therefore, a major goal of the present research was to investigate the possible cellular mechanisms underlying the effect of anethole on the neural excitability and action potential characteristics in snail neurons. Methods: Intracellular recordings were made under the current clamp condition on F1 cells of Helix aspersa. Following extracellular application of anethole (0.5% or 2%), changes in the firing pattern and action potential parameters were assessed and compared to control condition. Results: Application of anethole (0.5% and 2%) led to a significant increase in the action potential amplitude and a reduction in the peak area and time to peak. In the presence of 0.5% anethole, the after hyperpolarization (AHP) amplitude was significantly decreased, while the firing frequency of neurons was increased. However, 2% anethole did not affect the AHP amplitude, but significantly reduced the firing frequency of action potentials. Conclusion: Based on the effect of anethole on the action potential parameters, it can be concluded that it probably affects the voltage gated ion channels function, including Ca2+ channels and/or Ca2+ dependent K+ channels activity.