1. K 305
23 May 03
03/05/23 1

2. Regulation of E-C Coupling
SNS via the adrenergic b1 receptor
Gs- AC and PKA and phosphorylation of:
DHPR (b subunit) - increasing open probability
phospholamban -increasing SERCA2A activity
TnI - increasing off loading of Ca from TnC
RyR - increasing fractional release
03/05/23

3. E-C coupling in mammalian heart
03/05/23

4. Regulation of E-C Coupling
SNS via the adrenergic b1 receptor
Gs- AC and PKA and phosphorylation of:
DHPR (b subunit) - increasing open probability
phospholamban -increasing SERCA2A activity
TnI - increasing off loading of Ca from TnC
RyR - increasing fractional release
PNS – ACh via the muscarinic receptor
Gi – reduced AC and PKA
03/05/23

5. Regulation of E-C Coupling
Hormones (glucagon, thyroxine etc)
Drugs (may simulate SNS effects)
Ouabain or digitalis
Inhibits Na+ K+ ATPase
Increases [Na+]I
Decreases Ca2+ efflux via NCX
Increases SR Ca2+ loading / release
Positive inotropic agent
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6. 03/05/23

7. Regulation of Cardiac Output
Inotropic agents affect contractility
Chronotropic agents affect heart rate
Lusitropic agents affect relaxation
03/05/23

8. Regulation of Cardiac Output
Heart rate
Stroke Volume
Contractility
Starling Relationship
03/05/23