Intracellular calcium does not directly modulate cardiac pacemaker (if) channels.
A study on the cardiac pacemaker current if in inside-out macro-patches of sino-atrial (SA) node cells has recently demonstrated that if channels are directly activated by intracellular cAMP. Using the same preparation, here we investigate the possibility that internal Ca2+ ions play a role in the modulation of if channels. Our results indicate that Ca2+ ions do not have a direct activating effect on if.
Zaza
A
A
Università di Milano, Dipartimento di Fisiologia e Biochimica Generali, Italy.
Maccaferri
G
G
Mangoni
M
M
DiFrancesco
D
D
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D008564:Membrane Potentials; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000378:metabolism*
D007473:Ion Channels; D000242:Cyclic AMP; D002118:Calcium