Epinephrine increases hea rate by its action on:
Phospholamban is a SERCA-associated protein in the cardiac muscle. Epinephrine/NE (or b-agonists), act their receptors on the cardiac muscle cells, increase cAMP -->increases cAMP-dependent protein kinases--> phosphorylation of phospholamban-->rapid removal of sarcoplasmic Ca++ by the SERCA. The rate of relaxation increases, diastole duration is shoened and hea rate increases. This is in addition to the direct effect of epinephrine on the pacemaker cells. Calsequestrin and calreticulin are Ca++-binding proteins in all types of muscles. They bind and buffer the Ca++ which is removed from sarcoplasm during relaxation of the muscle. Calmodulin is Ca++-binding protein in the smooth muscle. When Ca++ binds with calmodulin, there is activation of myosin light chain kinase (MLCK), as a consequence of which there would be actin-myosin interaction (contraction).
Calmodulin
Calsequestrin
Calreticulin
Phospholamban
Cell Membrane and transpo protiens