Effects of gallium chloride on changes in action potentials and contraction in guinea pig ventricular muscle.
The electrophysiological effects of gallium chloride (Ga ) and its activity on arrhythmias induced by digitalis were investigated in guinea pig papillary muscle. KCl microelectrodes were used to record transmembrane electrical activity from Purkinje cells from the papillary muscle of guinea pig hearts during superfusion and electrical stimulation in vitro at 37 degrees C. Myocardial contractility was continuously monitored. Ga was superfused alone in cumulative concentrations(4.5 . 10(-5) to 3.6 . 10(-4) M). Arrhythmias were induced by a superfusion of Digitoxin (7.5 . 10 (-7) M). A superfusion of Ga (4.5 . 10(-5), 9 . 10(-5), 1.8 . 10(-4) M and 3.6 . 10(-4) M) was started 20 min later and maintained for 70 min. Ga alone produced a dose dependent reduction of action potential duration and contractility. Ga potentiated the decrease in the amplitude and duration of the action potential induced by Digitoxin. The incidence of arrhythmias was immediately reduced by two concentrations of Ga (4.5 . 10(-5) and 9 . 10(-5) M) in the digitalized papillary muscles. It is concluded that Ga inhibits calcium movements and has negative inotropic and antidysrhythmic effects.
Kantelip
J P
JP
Laboratorie de Pharmacologie Fondamentale, Faculté de Médecine, Besançon, France.
Millart
H
H
Leperre
A
A
Mougin
F
F
Didier
J M
JM
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D003864:Depression, Chemical; D004072:Digitonin / Q000633:toxicity; D004347:Drug Interactions; D005069:Evaluation Studies as Topic; D005708:Gallium / Q000494:pharmacology*; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006352:Heart Ventricles / Q000187:drug effects; D066298:In Vitro Techniques; D007202:Indicators and Reagents / Q000633:toxicity; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects / Q000502:physiology
D000889:Anti-Arrhythmia Agents; D007202:Indicators and Reagents; C034163:gallium chloride; D005708:Gallium; D004072:Digitonin