title: Rapid calcium-current kinetics in synaptic terminals of goldfish retinal bipolar neurons.
abstract: Onset and offset of calcium current in response to short, depolarizing voltage pulses were studied in giant synaptic terminals of goldfish bipolar neurons. Tail-current decays were extremely rapid (80 micros at -70 mV), and exponentially slowed at more positive repolarization potentials. The amplitude of tail current following voltage pulses varied with the pulse amplitude, according to a Bolzmann distribution with a V1/2 of -27.6 mV and a slope factor of 13.8 mV. When interpreted with a Hodgkin-Huxley model, calcium-current onset was best described by m2 kinetics and a time constant (tau(m)) of 0.62 ms at -10 mV. The kinetics of calcium-current onset and offset are at least two- to threefold faster than those described in other native cells. Combined with other recent data, the results suggest that the rapid kinetics may participate in a fast signaling mode in the goldfish ON-center pathway.
authors.affiliation: Department of Neurobiology and Behavior, State University of New York, Stony Brook, USA.
authors.forename: S
authors.initials: S
authors.lastname: Mennerick
authors.forename: G
authors.initials: G
authors.lastname: Matthews
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D004553:Electric Conductivity; D006054:Goldfish / Q000502:physiology*; D007700:Kinetics; D008959:Models, Neurological; D009474:Neurons / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000378:metabolism*; D013997:Time Factors
chemical_list: D015220:Calcium Channels