Actions of G-strophanthin, adrenaline and acetylcholine on bullfrog ventricular muscle in the sodium-free lithium solution.
The actions of g-strophanthin, adrenaline and acetylcholine on the action potential of bullfrog ventricular muscle were studied in the Na+ -free Li+ solution, in order to examine if these actions are associated with the change of active Na+ transport. The action of g-strophanthin on the action potential, being observed in the Ringer solution, completely disappeared in the Na+-free Li+ solution. On the other hand, the actions of adrenaline and acetylcholine remained unchanged in the Na+ -free Li+ solution, except the hyperpolarizing action of adrenaline on the resting membrane. These results suggest that changes of the action potential by g-strophanthin are secondary events caused by the change of active Na+ transport, whereas those by adrenaline and acetylcholine are primary events due to the change of membrane permeability.
D000109:Acetylcholine / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001001:Anura; D004837:Epinephrine / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008094:Lithium / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology*; D011892:Rana catesbeiana; D012964:Sodium / Q000502:physiology
D010042:Ouabain; D008094:Lithium; D012964:Sodium; D000109:Acetylcholine; D004837:Epinephrine