Model is underconstrained. The following variables couldn't be defined: * CaPr in component free_protein_calcium_binding_sites * Pr in component free_protein_calcium_binding_sites * J_ch in component flux_through_the_channels * J_leak in component leak_flux * J_pump in component calcium_pump * Ca_ER in component ER_calcium * delta_psi in component potential_difference * a in component potential_difference * b in component potential_difference * c in component potential_difference * E_Ca in component calcium_reversal_potential * g_Ca in component flux_through_the_channels * k_ch in component flux_through_the_channels * d/dt Pr in component free_protein_calcium_binding_sites * d/dt Ca_cyt in component cytosolic_calcium