title: Current-voltage relationships of repetitively firing neurons.
abstract: The current-voltage curves of repetitively firing neurons show non-linearities in the subthreshold region. Microsurgically isolated molluscan neuron somata were studied under voltage clamp using ramp voltage command signals. During the depolarizing 1/2 cycle a region of negative slope conductance was observed. Ion substitution experiments suggest that this results from non-inactivating or slowly inactivating Na+ and Ca2+ currents. The hyperpolarizing 1/2 cycle reveals a hysteresis effect which results at least in part from a Ca2+ activated 5+ current. Similar characteristics have been described in bursting neurons. Their occurrence in the non-bursting neurons studied here shows that they are not unique to this class of neurons and suggests that their primary contribution is to create electrical instability necessary for repetitive firing.
mesh_terms: D000818:Animals; D004553:Electric Conductivity; D007473:Ion Channels / Q000378:metabolism; D008564:Membrane Potentials; D008959:Models, Neurological; D008974:Mollusca; D009474:Neurons / Q000502:physiology*
chemical_list: D007473:Ion Channels