Excess noise in modified conductance states following the interaction of ryanoids with cardiac ryanodine receptor channels.
The interaction of ryanodine with the ryanodine receptor (RyR) produces profound changes in channel function. Open probability increases dramatically and conductance is reduced. In this report we describe differences in the properties of reduced conductance states produced by the interaction of ryanodine derivatives with RyR channels. Some reduced conductance states are considerably noisier than the normal open state of the RyR channel. Inspection and analysis of these events reveals that the excess noise arises from transitions between two conductance states. Following the interaction of certain ryanodine derivatives, RyR channels undergo transitions between two conformations with slightly different ion-handling properties.
Tanna
Bhavna
B
Cardiac Medicine, National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Dovehouse Street, SW3 6LY, London, UK. t.bhavna@ic.ac.uk
Welch
William
W
Ruest
Luc
L
Sutko
John L
JL
Williams
Alan J
AJ
D000818:Animals; D004553:Electric Conductivity; D066298:In Vitro Techniques; D008081:Liposomes; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D011487:Protein Conformation / Q000187:drug effects; D012433:Ryanodine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D012756:Sheep
C113821:21-amino-9-hydroxyryanodine; D008081:Liposomes; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine