Neuron-silicon junction with voltage-gated ionic currents.
We recorded the signals of firing Retzius neurons from Hirudo medicinalis by field-effect transistors. The axon stump of dissociated cells was attached to an open gate coated with concanavalin A. We observed a new type of neuron-transistor coupling: the extracellular voltage transients beneath the neuron were dominated by a negative peak during the rising phase of the action potential with a weaker positive transient in the falling phase. The biphasic response was opposite to the signal of capacitive coupling. We simulated the junction on the basis of the Hodgkin-Huxley equations. We found that the negative transient corresponded to an inward flow of sodium and the positive response to an outward flow of potassium. The field-effect transistors are able to probe the local flow of ionic currents in a membrane which is hidden in the region of cell adhesion. They may become a novel tool in neuroscience.
Schätzthauer
R
R
Department Membrane and Neurophysics, Max-Planck-Institute for Biochemistry, Martinsried/München, Germany.
Fromherz
P
P
D000818:Animals; D003208:Concanavalin A; D004594:Electrophysiology / Q000295:instrumentation; D005110:Extracellular Space / Q000502:physiology; D015640:Ion Channel Gating / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology*; D007865:Leeches; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D012825:Silicon; D014014:Tissue Adhesives; D014173:Transistors, Electronic
D007473:Ion Channels; D014014:Tissue Adhesives; D003208:Concanavalin A; D012825:Silicon