title: Estimate of the chloride concentration in a central glutamatergic terminal: a gramicidin perforated-patch study on the calyx of Held.
abstract: The function of presynaptic terminals is regulated by intracellular Cl-, the levels of which modify vesicular endocytosis and transmitter refilling and mediate the effects of presynaptic ligand-gated Cl- channels. Nevertheless, the concentration of Cl- in a central nerve terminal is unknown, and it is unclear whether terminals can regulate Cl- independently of the soma. Using perforated-patch recording in a mammalian synapse, we found that terminals accumulate Cl- up to 21 mm, between four and five times higher than in their parent cell bodies. Changing [Cl-] did not alter vesicular glutamate content in intact terminals, unlike in vitro experiments. Thus, glutamatergic terminals maintain an elevated Cl- concentration without compromising synaptic transmission.
authors.affiliation: Oregon Hearing Research Center, Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA.
authors.forename: Gareth D
authors.initials: GD
authors.lastname: Price
authors.forename: Laurence O
authors.initials: LO
authors.lastname: Trussell
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology*; D002712:Chlorides / Q000032:analysis / Q000502:physiology*; D018698:Glutamic Acid / Q000502:physiology*; D005998:Glycine / Q000494:pharmacology; D006096:Gramicidin / Q000494:pharmacology*; D066298:In Vitro Techniques; D051379:Mice; D008813:Mice, Inbred ICR; D018408:Patch-Clamp Techniques / Q000379:methods*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002712:Chlorides; D006096:Gramicidin; D018698:Glutamic Acid; D005998:Glycine