The inhibitory effects of nano-Ag on voltage-gated potassium currents of hippocampal CA1 neurons

The application of the nano-sized materials continues to grow at a rapid rate in the fields of medicine, biotechnology, and environmental technology. Voltage-gated potassium currents play a key role in excitable cellular viability and function, especially in the central nervous system. The aim of this study was to investigate the actions of silver nano-particles (nano-Ag) on voltage-activated potassium currents in hippocampal CA1 neurons using whole cell patch-clamp technique. The hydrodynamic mean diameter of nano-Ag (10(-5) g mL(-1)) was 223.9 nm in artificial cerebrospinal fluid (ACSF). Both types, transient potassium (I-A) and delayed rectifier potassium (I-K) current amplitudes were inhibited by the nano-Ag (10(-5) g mL(-1)). The nano-Ag particles produced a hyperpolarizing shift in the activation-voltage curve of I-K and inactivation-voltage curve of I-A and also delayed the recovery of I-A from inactivation. The results suggest that nano-Ag may have potential to alter the excitability of neurons by depressing the potassium channels. (C) 2010 Wiley Periodicals, Inc. Environ Toxicol 26: 552-558, 2011.