Heart Wall - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 315

Table 6.13. Regulation of pacemaker currents (Source: [ 601 ]).

Effector Target Effect

Ca 2 + Na + -Ca 2 + exchanger Activation

Delayed rectifier K + channel Activation

H + Inward rectifier K + channel

Inhibition

Ca 2 + channel Inhibition

Na + -HCO 3 cocarrier

β

-Adrenergic Gs-ACase-cAMP-PKA

agonist Ca V 1.2 channel Activation

Delayed rectifier K + channel Activation

α 1-Adrenergic Gq-PLC-DAG-PKC

Delayed rectifier K + channel

agonist Activation

Muscarinic Gi-ACase Inhibition

Ach-activated K + channel agonist Activation

Adenosine ACase

Adenosine-sensitive K + channel Activation

ATP-sensitive K + channel ATP Inhibition

Ca 2 + pump Activation

Na + -K + pump Activation

IKr

IKs IKur

IKto

IfNa

IfK

INa

IKb

INab

IKACh

INaK

IKATP

INaCa

ICaT

ICab

ICaL

ICap

Fig. 6.4 Main ionic currents across the sarcolemma of sinoatrial node and atrial cells, associated
with the action potential (Sources: [ 602 , 603 ]; ICaL [ i Ca , L ]: L-type Ca 2 + current; ICaT [ i Ca , T ]: T-
type Ca 2 + current; ICap [ i Ca , p ]: sarcolemmal Ca 2 + pump current; ICab [ i Ca , b ]: background Ca 2 +
current; IfK [ i f K ]: hyperpolarization-activated K + “funny” current; IKur, IKr, IKs [ i K , ur , i K , r , i K , s ]:
ultrarapid, rapid, and slow K + delayed rectifier current; IKb [ i K , b ]: background K + current; INa
[ i Na ]: inward Na + current; INab [ i Na , b ]: background Na + current; INaCa [ i NaCaX ]: Na + -Ca 2 +
exchanger current; INaK [ i NaK AT P ]: Na + -K + pump current; IfNa [ i f Na ]: hyperpolarization-activated
Na + “funny” current).