ELECTRICAL OSCILLATIONS OF ISOLATED BRAIN MICROTUBULES

GUTIERREZ BC; CANTERO MR; CANTIELLO HF

Congreso; Annual Meeting of the Biophysical Society; 2021

Microtubules (MTs) are important cytoskeletal structures engaged in a number of specific cellular activities, including vesicular traffic and cell division, as well as information transfer within neuronal processes. MTs also are highly charged polyelectrolytes. Recent in vitro electrophysiological studies indicate that different brain MT assemblies, including two-dimensional (2D) sheets (MT sheets) and macrotube bundles, generate highly synchronous electrical oscillations (Cantero et al. Sci Rep, 2016 & 2018). Although taxol-stabilized isolated MTs are capable of amplifying electrical signals, no information is heretofore available as to whether isolated they also engage in electrical oscillations. Herein we tested the effect of voltage clamping on the electrical properties of non-taxol stabilized isolated brain MTs. Electrical oscillations were observed at holding potentials between ±200 mV. Mean oscillatory currents were linear with respect to holding potential, with a change in conductance from 59.6 ± 3.6 nS to 160.8 ± 7.6 nS (n = 3) after loose-patch correction. The average change in conductance was much higher than previously reported for more complex MT structures. Spectral analysis of the electrical currents also disclosed a richer oscillatory response as compared to voltage clamped MT sheets from the same preparation. The findings are consistent with the possibility that MT assemblies (i.e. bundles, sheets) may render more coherent responses at given oscillatory frequencies such as entraining to oscillate together. The oscillatory behavior of isolated brain MTs is consistent with that of ?ionic-based? transistors whose activity is synchronized in higher MT structures. The ability of MTs to generate, propagate, and amplify electrical signals may have important implications in neuronal computational capabilities.