Embodiments of calcium channel agonists, as well as methods of making and using the calcium channel agonists, are disclosed. The disclosed calcium channel agonists and corresponding salt forms have a structure according to general formula I:wherein each bond depicted as “” is a single bond or a double bond as needed to satisfy valence requirements； Z1, Z2, Z3, Z4, and Z5 independently are nitrogen or carbon； R1 and R3 are alkyl； R2 is alkyl, aryl, heteroaryl, arylalkyl, or heteroarylalkyl； and R4 is alkyl or hydroxyalkyl.
