Rapid effects of cytochalasin-D on contraction and intracellular calcium in single rat ventricular myocytes.
Contraction and intracellular calcium ([Ca2+]i) transients were recorded using a video edge detector and fluorescence spectrophotometry, respectively, in rat ventricular myocytes at 22-24 degreesC stimulated at a frequency of 1 Hz. Application of the F-actin disrupter cytochalasin-D (Cyt-D) caused a large reduction in the amplitude of contraction and a small increase in the [Ca2+]i transient. These responses began within a few seconds of application and were complete after 2 min of exposure. Phase-plane relationships of contraction and [Ca2+]i were consistent with cytochalasin-D causing a decrease in myofilament responsiveness to Ca2+.
Howarth
F C
FC
Department of Physiology, University of Leeds, Leeds, LS2 9NQ, UK.
Boyett
M R
MR
White
E
E
D000199:Actins / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology*; D004558:Electric Stimulation; D005260:Female; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects*; D007424:Intracellular Fluid / Q000737:chemistry / Q000187:drug effects*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D013050:Spectrometry, Fluorescence
D000199:Actins; D015638:Cytochalasin D; D002118:Calcium