Vitamins C and E modulate neuronal potassium currents.
We investigated the effects of vitamins C and E on the delayed-rectifier potassium current (IK(DR)), which is important in repolarizing the membrane potential, and on the transient A-type potassium current (IK(A)), which regulates neuronal firing frequency. The whole-cell patch-clamp technique was used to measure the currents from cultured Drosophila neurons derived from embryonic neuroblasts. The membrane potential was stepped to different voltages between -40 and +60 mV from a holding potential of -80 mV. IK(DR) and IK(A) measured in the vitamin C-containing solution (IK(DR) 305 +/- 16 pA, IK(A) 11 +/- 2 pA) were smaller than those measured in the control solution (488 +/- 21 pA, IK(A )28 +/- 3 pA). By contrast, IK(DR) and IK(A) measured in the vitamin E-containing solution (IK(DR) 561 +/- 21 pA, IK(A )31 +/- 3 pA) were greater than those measured in the control solution (422 +/- 15 pA, 17 +/- 2 pA). These results indicate that vitamins C and E can modulate potassium current amplitudes and possibly lead to altered neuronal excitability.
Alshuaib
Waleed B
WB
Department of Physiology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait. waleeds@hsc.edu.kw
Mathew
Mini V
MV
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D002478:Cells, Cultured; D004331:Drosophila melanogaster / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000187:drug effects; D005260:Female; D008564:Membrane Potentials / Q000187:drug effects / Q000528:radiation effects; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques / Q000379:methods; D011188:Potassium / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D014810:Vitamin E / Q000494:pharmacology*
D000975:Antioxidants; D024661:Potassium Channels, Inwardly Rectifying; D014810:Vitamin E; D001205:Ascorbic Acid; D011188:Potassium