title: [Predominant blocking of fast potassium current channels in mollusk neurons by 4-aminopyridine].
abstract: Blocking effects of 4-aminopyridine (4-AP) on ionic currents were studied in Lymnaea stagnalies neurones using the suction pipette method for voltage clamp and internal perfusion. When applied externally, 4-AP blocks transient potassium current as well as early inward and delayed outward currents, apparent dissociation constants being 0.4 mM (E = -40-- -30 mV); 6.5 mM (E = -10-- -20 mV); 24 mM (E = 20 mV), resp. Intracellular 4-AP changes the constants to 0.85, 77, 55 mM. An experimental study of a possible role of the transient potassium channels in the regulation of molluscan unit activity seems to be effective when 4-AP is applied internally as it blocks then the transient potassium channels in a selective manner.
mesh_terms: D015761:4-Aminopyridine; D000631:Aminopyridines / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005724:Ganglia / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D007700:Kinetics; D008195:Lymnaea; D011188:Potassium / Q000378:metabolism*
chemical_list: D000631:Aminopyridines; D007473:Ion Channels; D015761:4-Aminopyridine; D011188:Potassium
vernacular_title: Preimushchestvennoe blokirovanie 4-aminopiridinom kanalov bystrogo kalievogo toka neĭronov molliuska.