title: 9-Amino-1,2,3,4-tetrahydroacridine (THA) is a potent blocker of cardiac potassium channels.
abstract: 1. 9-Amino-1,2,3,4-tetrahydroacridine (THA) is a compound with structural similarity to the K+ channel blocker 4-aminopyridine. It was investigated for its effects on myocardial membrane currents in guinea-pig isolated ventricular myocytes. 2. THA prolonged the transmembrane action potential and decreased the amplitude of its plateau in a reversible manner. 3. Voltage-clamp experiments showed that THA reduced the inwardly rectifying and the time-dependent outward K+ currents as well as the slow inward Ca2+ current. 4. The degree of block of the inwardly rectifying K+ current depended on the membrane potential, being more pronounced at more positive potentials.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000609:Aminoacridines / Q000494:pharmacology*; D000818:Animals; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D013619:Tacrine / Q000494:pharmacology*
chemical_list: D000609:Aminoacridines; D007473:Ion Channels; D013619:Tacrine; D011188:Potassium