Na⁺/Ca²⁺ Exchanger Expression and Function in a Rabbit Model of Myocardial Infarction

Abstract

In conclusion, reduced sorcin expression may be linked to the lower NCX activity in the rabbit model of LVD. Reduced NCX activity during diastole increases SR Ca(2+) content and Ca(2+) transient amplitude.

KB‐R7943, an inhibitor of the reverse Na+/Ca2+ exchanger, blocks N‐methyl‐D‐aspartate receptor and inhibits mitochondrial complex I

“…+80 mV) (Convery and Hancox, 1999;Watanabe and Kimura, 2000). For comparison, we evaluated Ni 2+ -sensitivitiy of the ramp currents ( Figure 3D), which has been previously attributed to NCX activity (Smith et al, 2006;Reppel et al 2007). Memantine (10 mM), an NMDA receptor inhibitor (Chen et al, 1992), did not affect the ramp currents (not shown).…”

“…The NCX-mediated ion currents were recorded using voltage ramp protocol as described previously (Convery and Hancox, 1999). The composition of the electrode solution used for recording voltage ramp currents mediated by NCX was as follows: 20 mM KCl, 100 mM K-aspartate, 20 mM tetraethylammonium-Cl, 10 mM HEPES, 0.01 mM K-EGTA, 4.5 mM MgCl2 and 4 mM Na-ATP, pH 7.3 adjusted with KOH (Smith et al, 2006). The external solution used for recording ramp currents was as follows: 129 mM NaCl, 10 mM CsCl (to block K + channels), 3 mM KCl, 0.8 mM MgCl2, 1.8 mM CaCl2, 5 mM glucose, 10 mM Na-HEPES, pH 7.2, 65 mM sucrose, 0.01 mM nifedipine (to block voltagegated Ca 2+ channels), 0.02 mM ouabain and 0.001 mM TTX (to block Na + channels).…”

Collapsin Response Mediator Protein 2 (CRMP2) Interacts with N-Methyl-d-aspartate (NMDA) Receptor and Na+/Ca2+ Exchanger and Regulates Their Functional Activity

“…Data were collected using the Pulse program (HEKA Elektronik, Lambrecht/Pfalz, Germany). The electrode solution used for recording voltage ramp currents mediated by NCX rev contained 20 mM KCl, 100 mM potassium aspartate, 20 mM tetraethylammonium-Cl, 10 mM HEPES, 0.01 mM K-EGTA, 4.5 mM MgCl 2 , and 4 mM Na-ATP, pH 7.3, adjusted with KOH (24). The external solution used for recording currents contained 129 mM NaCl, 10 mM CsCl (to block K ϩ channels), 3 mM KCl, 0.8 mM MgCl 2 , 1.8 mM CaCl 2 , 5 mM glucose, 10 mM Na-HEPES, pH 7.2, 65 mM sucrose, 10 M nifedipine (to block voltage-gated Ca 2ϩ channels), 20 M ouabain (to inhibit Na ϩ /K ϩ -ATPase), and 1 M tetrodotoxin (to block Na ϩ channels).…”

“…Na ϩ /Ca 2ϩ exchange is electrogenic; therefore, it is possible to record ion currents mediated by NCX (32,33). Previously, this approach was used in experiments with cardiomyocytes (24,34). We successfully adapted this technique to neurons in culture (12,23) and have previously provided a detailed explanation as to why NCX rev activity, but not voltage-gated Ca 2ϩ channel activity, is the main contributor in generating these currents (30).…”

“…Consequently, in addition to Ca 2ϩ imaging, we used an electrophysiological, whole-cell, voltage ramp protocol to demonstrate NCX rev inhibition by TAT-CBD3. Ni 2ϩ , an NCX inhibitor (24,34), was used as a positive control. Ni 2ϩ (5 mM) significantly decreased (by 62 Ϯ 7%, n ϭ 5) the peak ion current generated by the voltage ramp, indicating that this current is predominantly mediated by NCX rev (Fig.…”