PT - JOURNAL ARTICLE AU - Price, Gareth D. AU - Trussell, Laurence O. TI - Estimate of the Chloride Concentration in a Central Glutamatergic Terminal: A Gramicidin Perforated-Patch Study on the Calyx of Held AID - 10.1523/JNEUROSCI.1660-06.2006 DP - 2006 Nov 01 TA - The Journal of Neuroscience PG - 11432--11436 VI - 26 IP - 44 4099 - http://www.jneurosci.org/content/26/44/11432.short 4100 - http://www.jneurosci.org/content/26/44/11432.full SO - J. Neurosci.2006 Nov 01; 26 AB - 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.