Effects of sodium metabisulfite on potassium currents in acutely isolated CA1 pyramidal neurons of rat hippocampus.
The effects of sodium metabisulfite (SMB), a food preservative mostly used in food and drug industries, on voltage-dependent potassium currents in acutely isolated hippocampal CA1 pyramidal neurons of rat were studied using the whole-cell patch-clamp techniques. SMB increased transient outward potassium current (IA) and delayed rectifier potassium current (IK) in a concentration-dependent manner. 10 microM SMB shifted the steady-state activation curve of IK to more negative potentials, and the steady-state inactivation curves of IA and IK to more positive potentials. Time to peak of IA was not affected, but the decay of IA was delayed by SMB. However, the activation and inactivation time constants of IK were both decreased by SMB. These results suggested that SMB differently affected IA and IK, and it would decrease the excitability of hippocampal neuron by increasing potassium currents.
Meng
Ziqiang
Z
Institute of Environmental Medicine and Toxicology, Research Center of Environmental Science and Engineering, Shanxi University, Wucheng Road 36, Taiyuan 030006, PR China. zqmeng@sxu.edu.cn
Nie
Aifang
A
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005520:Food Preservatives / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000493:pharmacokinetics*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013447:Sulfites / Q000494:pharmacology*
D005520:Food Preservatives; D015221:Potassium Channels; D013447:Sulfites; C005200:sodium metabisulfite; D011188:Potassium