YS-035 is a verapamil derivative that dose-dependently blocks calcium uptake via Na+/Ca2+ exchange in diverse types of cells (Ki = 28 μM). It inhibits calcium uptake by muscle cells, brain synaptosomes, and kidney fibroblasts. YS-035 also prevents calcium release from mitochondria induced by Ruthenium Red but not by uncouplers, respiratory inhibitors, or a chelating agent. YS-035 is used to characterize the role of calcium currents in smooth muscle and neuronal electrophysiology.