Power Spectral Density Analysis of Purkinje Cell Tonic and Burst Firing Patterns From a Rat Model of Ataxia and Riluzole Treated

Zebrafish-Based Screening of Antiseizure Plants Used in Traditional Chinese Medicine: Magnolia officinalis Extract and Its Constituents Magnolol and Honokiol Exhibit Potent Anticonvulsant Activity in a Therapy-Resistant Epilepsy Model

With the aim to discover interesting lead compounds that could be further developed into compounds active against pharmacoresistant epilepsies, we first collected 14 medicinal plants used in traditional Chinese medicine (TCM) against epilepsy. Of the six extracts that tested positive in a pentylenetetrazole (PTZ) behavioral zebrafish model, only the ethanol and acetone extracts from Magnolia officinalis (M. officinalis) also showed effective antiseizure activity in the ethylketopentenoate (EKP) zebrafish model. The EKP model is regarded as an interesting discovery platform to find mechanistically novel antiseizure drugs, as it responds poorly to a large number of marketed anti-epileptics. We then demonstrated that magnolol and honokiol, two major constituents of M. officinalis, displayed an effective behavioral and electrophysiological antiseizure activity in both the PTZ and the EKP models. Out of six structural analogues tested, only 4-O-methylhonokiol was active and to a lesser extent tetrahydromagnolol, whereas the other analogues (3,3'-dimethylbiphenyl, 2,2'-biphenol, 2-phenylphenol, and 3,3',5,5'-tetra-tert-butyl-[1,1'-biphenyl]-2,2'-diol) were not consistently active in the aforementioned assays. Finally, magnolol was also active in the 6 Hz psychomotor mouse model, an acute therapy-resistant rodent model, thereby confirming the translation of the findings from zebrafish larvae to mice in the field of epilepsy. We also developed a fast and automated power spectral density (PSD) analysis of local field potential (LFP) recordings. The PSD results are in agreement with the visual analysis of LFP recordings using Clampfit software and manually counting the epileptiform events. Taken together, screening extracts of single plants employed in TCM, using a combination of zebrafish- and mouse-based assays, allowed us to identify allyl biphenol as a chemical scaffold for the future development of compounds with potential activity against therapy-resistant epilepsies.

Ultrasensitive System for Electrophysiology of Cancer Cell Populations: A Review

Bioelectricity is the electrical activity produced by living organisms. Understanding the role of bioelectricity in a disease context is important as it contributes to both disease diagnosis and therapeutic intervention. Electrophysiology tools work well for neuronal cultures; however, they are limited in their ability to detect the electrical activity of non-neuronal cells, wherein the majority of cancers arise. Electronic structures capable of detecting and modulating signaling, in real-time, in electrically quiescent cells are urgently required. One of the limitations to understanding the role of bioelectricity in cancer is the inability to detect low-level signals. In this study, we review our latest advances in devising bidirectional transducers with large electrode areas and concomitant low impedances. The resulting high sensitivity is demonstrated by the extracellular detection of electrical activity in Rat-C6 glioma and prostate cancer (PC-3) cell populations. By using specific inhibitors, we further demonstrated that the large electrical activity in Rat-C6 glioma populations is acidosis driven. For PC-3 cells, the use of a calcium inhibitor together with the slowly varying nature of the signal suggests that Ca²⁺ channels are involved in the cohort electrogenicity.