Suppression of channel conductance by diacetyl monoxime in guinea pig and embryonic chick cardiomyocytes.
OBJECTIVE
To examine the effects of diacetyl monoxime (DAM), and putative dephospohrylating agent, on conductance of the cardiac Ca, Na, and K channels.


METHODS
The Ca (ICa), Na (INa), and K (IK) currents were recorded in single ventricular myocytes from guinea pigs and chick embryos before and after addition of DAM using the whole-cell voltage-clamp technique.


RESULTS
DAM 10 mmol.L-1 reduced rapidly the amplitudes of ICa (by about 30%), INa (by about 25%), and IK (by 25%-50%) without alterations of the voltage-dependence.


CONCLUSIONS
DAM was a channel inhibitor of the unique type having nonselective phosphatase activities.
Sada
H
H
Department of Pharmacology, Yamaguchi University, College of Medicine, Ube, Japan.
Ban
T
T
Sperelakis
N
N
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D002801:Cholinesterase Reactivators / Q000494:pharmacology*; D003931:Diacetyl / Q000031:analogs & derivatives* / Q000494:pharmacology; D006168:Guinea Pigs; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials; D009206:Myocardium / Q000166:cytology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects; D015222:Sodium Channels / Q000187:drug effects
D015220:Calcium Channels; D002801:Cholinesterase Reactivators; D007473:Ion Channels; D015221:Potassium Channels; D015222:Sodium Channels; C004717:diacetylmonoxime; D003931:Diacetyl