I_Ca I_K I_SK I_DA C lambda n_infinity n tau_n 1 1 vn V sn gK n V VK 1 1 vm V sm gCa m_infinity V VCa gSK s_infinity V VK Ca 2 Ca 2 ks 2 1 1 va V sa h_infinity h tau_h 1 1 V vh sh I_A gA a_infinity h V VK fc alpha I_Ca kc Ca kPRL Ca 4