FIGURE 5.

Primary human Purkinje cell models. Simulated action potentials [transmembrane voltage (V_M)] and Ca²⁺ transients ([Ca²⁺]_i), model structure, simulated ion currents and fluxes, and special features are highlighted. Traces were simulated with human Purkinje cell models from Trovato 2020 (146), Sampson 2010 (145), and Stewart 2009 (143). Models were obtained from https://www.cellml.org/ or implemented based on the model equations. CaMKII, Ca²⁺/calmodulin-dependent protein kinase II; CSR, corbular sarcoplasmic reticulum; CYT, cytosol; I_Cab, background Ca²⁺ current; I_CaK, K⁺ flux through the L-type Ca²⁺ channel; I_Ca,L, L-type Ca²⁺ current; I_Ca,T, T-type Ca²⁺ current; I_f, hyperpolarization-activated cyclic nucleotide-gated “funny” current; I_K1, basal inward-rectifier K⁺ current; I_Kp, plateau K⁺ current; I_Kr, rapid delayed-rectifier K⁺ current; I_Ks, slow delayed-rectifier K⁺ current; I_Na, Na⁺ current; I_Na,late, persistent late Na⁺ current; I_Nab, background Na⁺ current; I_NaK, Na⁺-K⁺-ATPase current; I_NaCa, Na⁺/Ca²⁺ exchange current; I_pCa, plasmalemmal Ca²⁺-ATPase current; I_sus, sustained K⁺ current; I_to, transient outward K⁺ current; J_IP3R, inositol trisphosphate receptor Ca²⁺ flux; J_leak, Ca²⁺ leak from sarcoplasmic reticulum; J_rel, Ca²⁺-release flux from the sarcoplasmic reticulum; JSR, junctional sarcoplasmic reticulum; J_up, Ca²⁺ uptake flux into the sarcoplasmic reticulum; NSR, network sarcoplasmic reticulum; RyR(2/3), ryanodine receptor (type 2/3); SERCA(1/2), sarco(endo)plasmic reticulum Ca²⁺-ATPase (type 1/2); SL, subsarcolemmal space; SR, sarcoplasmic reticulum; SS, subspace Ca²⁺ domain.