title: Calcium currents in a vertebrate presynaptic nerve terminal: the chick ciliary ganglion calyx.
abstract: Ca currents (ICa) were recorded from presynaptic nerve terminals in the chick ciliary ganglion. Ciliary neurons are innervated by a single nerve terminal that extends over a wide area of the neuron surface to form a 'calyx'. The neurons were dissociated enzymatically with the calyx intact and the patch clamp technique was used in the whole cell mode to record ion currents. A small inward ICa (peak current 20-80 pA) was recorded that was blocked by external Cd. Only one component of ICa was detected. This was recruited at positive membrane potentials, exhibited no evidence of inactivation during a 25-ms depolarizing pulse, and deactivated rapidly. Thus, the ICa recorded in this vertebrate presynaptic nerve terminal was similar to the high-voltage activated, fast deactivating, current reported in other neurons.
authors.affiliation: NINDS Biophysics Laboratory, Bethesda, MD 20892.
authors.forename: E F
authors.initials: EF
authors.lastname: Stanley
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology*; D002642:Chick Embryo; D005726:Ganglia, Parasympathetic / Q000378:metabolism / Q000502:physiology*; D008564:Membrane Potentials; D009411:Nerve Endings / Q000502:physiology*
chemical_list: D002118:Calcium