Prof. Fabio Benfenati
(University of Genoa, Italy)
Optical technologies allowing modulation of neuronal activity at high spatio-temporal resolution are becoming paramount in neuroscience. We synthesized a novel light-sensitive azobenzene flanked by an azepane and two alkyl chains terminated with a pyridinium salt (Ziapin2). We demonstrate that Ziapin2 stably partition into the plasma membrane with affinity for lipid rafts, and causes thinning of the bilayer through trans-dimerization in the dark, resulting in an increased membrane capacitance at steady state. In neurons loaded with the compound, millisecond pulses of visible light induce a transient hyperpolarization followed by a delayed depolarization that triggers action potential firing. The fast hyperpolarization is attributable to a light-dependent decrease in capacitance due to membrane relaxation that follows azobenzene isomerization. The physiological effects are persistent and can be evoked in vivo up to 7 days after initial labelling of the mouse somatosensory cortex. The data demonstrate the possibility to trigger neural activity in vitro and in vivo by modulating membrane capacitance in the millisecond time scale, without directly affecting ion channels or local temperature.
Join Meeting: https://rediris.zoom.us/j/85645658116