[Pharmacologic and metabolic dependence of the delayed inactivated potassium outward current in the somatic membrane of snail neurons].
Peculiarities of pharmacological and metabolic sensitivities of delayed potassium outward current depending on extracellular calcium ions (IK(Ca(out)) have been studied in experiments on isolated intracellularly perfused Helix neurons. It is shown that verapamil depresses the amplitude and accelerates the inactivation of this current. Blocking effect of verapamil increases with extracellular Ca2+ concentration. Functioning of IK(Ca(out)) channels depends on the intracellular metabolic processes. The current amplitude decreases during the neuron perfusion. Lowering of the intracellular solution temperature to +10 degrees C brings about the analogous result. Addition of ATP (2 mmol/l) and Mg2+ (3 mmol/l) to the intracellular perfusate prevents a decrease of potassium current; intracellular introduction of the exogenous protein kinase C restores the amplitude of this current. Polymyxin B (10(-4) mol/l), a blocker of protein kinase C, depresses the potassium current sensitive to extracellular calcium ions. The possible mechanism of Ca2+ action on IK(Ca(out)) through phosphatidyl-inositol metabolism is discussed.
Martyniuk
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AE
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D006372:Helix, Snails / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D008274:Magnesium / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D010716:Phosphatidylinositols / Q000378:metabolism; D011112:Polymyxin B / Q000494:pharmacology; D011188:Potassium / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D010716:Phosphatidylinositols; D000255:Adenosine Triphosphate; D014700:Verapamil; D011493:Protein Kinase C; D008274:Magnesium; D011112:Polymyxin B; D011188:Potassium
Issledovanie farmakologicheskoĭ i metabolicheskoĭ zavisimosti zaderzhannogo inaktiviruiushchegosia kalievogo vykhodiashchego toka v somaticheskoĭ membrane neĭronov molliuskov.