Amyloid β protein-induced irreversible current in rat cortical neurones

THE effect of amyloid β protein (AβP) was examined in neurones dissociated from rat cortex using the nystatin perforated patch-clamp technique. AjSP at concentrations >10 nM induced an irreversible slow inward current associated with an increase in membrane conductance. The time lag until the appearance of the effect of AβP shortened in a concentration-dependent manner. When extracellular Na⁺ and Cl_-, and intracellular K⁺ were replaced by equimolar N-methyl glucamine, isothionate and Cs⁺, respectively, the membrane conductance and the reversal potential were not affected. Even when an internal solution including 1,2-bis(0-aminophenoxy)eth- ane-N,N,N’N’-tetraacetic acid (20 mM) was used, the effect of AβP did not alter. It is suggested that AβP binds to the neuronal membrane and opens non-selective ion channels, resulting in neuronal degeneration.