The mouse sino-atrial node expresses both the type 2 and type 3 Ca(2+) release channels/ryanodine receptors.
Ca(2+) released from intracellular Ca(2+) stores is shown to be involved in pacemaker activity in the sino-atrial (SA)-node. However, little is known about the molecular identity of the Ca(2+) release channel/ryanodine receptor (RYR) involved in pacemaker activity. We examined the mRNA distribution of three different RYR isoforms (RYR1, RYR2, and RYR3) in the mouse SA-node. RNase protection assay and in situ hybridization revealed that RYR2 mRNA expresses widely in the heart including the SA-node, while RYR3 mRNA expression is limited to the SA-node and to the right atrium. Thus, not only RYR2 but also RYR3 may participate in pacemaker activity.
Masumiya
Haruko
H
Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Japan. h-masumiya.bip@mri.tmd.ac.jp
Yamamoto
Hideyuki
H
Hemberger
Myriam
M
Tanaka
Hikaru
H
Shigenobu
Koki
K
Chen
S R Wayne
SR
Furukawa
Tetsushi
T
D000200:Action Potentials / Q000187:drug effects; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006325:Heart Atria / Q000378:metabolism; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D018408:Patch-Clamp Techniques; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics* / Q000378:metabolism; D012849:Sinoatrial Node / Q000378:metabolism*
D020033:Protein Isoforms; D012333:RNA, Messenger; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D002118:Calcium