Interplay between Na⁺/Ca²+ Exchangers and Mitochondria in Ca²+ Clearance at the Calyx of Held

Abstract

The clearance of Ca 2ϩ from nerve terminals is critical for determining the build-up of residual Ca 2ϩ after repetitive presynaptic activity. We found previously that K

An Essential Role for the K+-dependent Na+/Ca2+-exchanger, NCKX4, in Melanocortin-4-receptor-dependent Satiety

“…9 and 10). Previous studies have demonstrated that NCKX exchangers typically play a significant role in Ca 2ϩ homeostasis in environments where Ca 2ϩ flux is high and intracellular Ca 2ϩ levels rise substantially, in a temporally and/or spatially restricted manner (3,55). This suggests that NCKX4 may be localized in close proximity to the entry pathways that control Ca 2ϩ signaling downstream from the MC4R (see model in Fig.…”

Target Cell-Specific Involvement of Presynaptic Mitochondria in Post-Tetanic Potentiation at Hippocampal Mossy Fiber Synapses

“…2؉ buffering during HFS at large and small MFBs Mitochondria have been suggested as a Ca 2ϩ sequestration mechanism at the axon terminals of many synapses (Tang and Zucker, 1997;David et al, 1998;David and Barrett, 2000;Billups and Forsythe, 2002;Suzuki et al, 2002;Kim et al, 2005;GarciaChacon et al, 2006 (Fig. 3Aa,Ab, black traces).…”

Cytosolic Ca2+ Buffers

“…The comparison is primarily focused on excitable cells, mostly neurons (for a more detailed role on mitochondria and Ca 2þ signaling, see Rimessi et al 2008 andSzabadkai andDuchen 2008). In the large glutamatergic presynaptic terminals of the calyx of Held, mitochondria contribute to increase the rate in [Ca 2þ ] i decay, when peak [Ca 2þ ] i is .2.5 mM (Kim et al 2005). This mitochondria-mediated increase in [Ca 2þ ] i decay closely resembles the action of the "slow buffer" PV in the same terminals (Muller et al 2007).…”