Role of cardiac Ca2+ Channels Nodal cells initiate and propagate action potentials- SLOW Non nodal cells controls action potential duration contraction
22 Role of Cardiac Ca2+ Channels ➢ Nodal cells ➢ initiate and propagate action potentials- SLOW ➢ Non nodal cells ➢ controls action potential duration ➢ contraction
Ca2+CHANNEL BLOCKERS AND THE CARDIAC CELL ACTION POTENTIAL CONTROL DILTIAZEM地尔硫卓 10 uMol/L 30 30 HMOI/L CONTROL 30 MME
23 Ca2+CHANNEL BLOCKERS AND THE CARDIAC CELL ACTION POTENTIAL DILTIAZEM 地尔硫卓 10 µMol/L 30 µMol/L 10 30 10 FORCE TIME CONTROL CONTROL 30
Ion channels in atrial cells Same as for ventricular cells Less pronounced plateau due to different balance of voltage-gated Ca2+ and K channels ATRIUM Ⅴ ENTRICLE 0 -90mv -90my 24
24 Ion Channels in Atrial Cells ➢ Same as for ventricular cells ➢ Less pronounced plateau due to different balance of voltage-gated Ca2+ and K channels mv 0 -90mv mv 0 -90mv ATRIUM VENTRICLE
OVERVIEW OF SPECIFIC EVENTS IN THE VENTRICULARACNON POTENTIAL 25
25 OVERVIEW OF SPECIFIC EVENTS IN THE VENTRICULAR ACTION POTENTIAL
Activation fast Inactivation Na OUTSIDE Plasma gate At rest membrane (Em=-75mV) INSIDE Na B OUTSIDE Immediately after depolarization INSIDE OUTSIDE 5 msec after depolarization (Em=-50mV) INSIDE Choate
26 Activation & Fast Inactivation