Single calcium channels on a cholinergic presynaptic nerve terminal.
The calyx-type synapse of the chick ciliary ganglion was used to examine single calcium channels in a vertebrate cholinergic presynaptic nerve terminal by means of the cell-attached, patch-clamp technique. Calcium channels were recorded on the internal, transmitter-release face of the nerve terminal, but were not detected on the external face. These channels were recruited at -30 mV, with maximum activation at about +30 mV, and were sometimes clustered at high densities. Single-channel conductance estimates with voltage-pulse or -ramp techniques gave values of 11-14 pS with 110 mM barium, which is in the intermediate, N-type range for calcium channels on a control neuron. This nerve terminal calcium channel, termed the NPT-type, may link action potentials to transmitter release at many vertebrate fast-transmitting synapses.
Stanley
E F
EF
National Institutes of Neurological Diseases and Stroke, Laboratory of Biophysics, National Institutes of Health, Bethesda, Maryland 20892.
D000818:Animals; D001464:Barium / Q000502:physiology; D015220:Calcium Channels / Q000378:metabolism* / Q000502:physiology; D002642:Chick Embryo; D004553:Electric Conductivity; D005726:Ganglia, Parasympathetic / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D009411:Nerve Endings / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D012583:Schwann Cells / Q000378:metabolism; D013569:Synapses / Q000502:physiology*
D015220:Calcium Channels; D001464:Barium