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Alzheimer amyloid aβ1–42 channels: Effects of solvent, pH, and congo red
Author(s) -
Hirakura Yutaka,
Lin MengChin,
Kagan Bruce L.
Publication year - 1999
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19990815)57:4<458::aid-jnr5>3.0.co;2-4
Subject(s) - neurotoxicity , congo red , biophysics , amyloid (mycology) , chemistry , ion channel , lipid bilayer , senile plaques , biochemistry , alzheimer's disease , membrane , biology , disease , toxicity , medicine , pathology , inorganic chemistry , receptor , organic chemistry , adsorption
Substantial genetic and biochemical evidence implicates amyloid peptides (A|fg) in the etiology of Alzheimer's Disease (AD). Recent evidence indicates that A|fg1–42 is the predominant species in the hallmark senile amyloid plaque of AD. Furthermore, A|fg1–42 forms aggregates inside lysosomes of cultured neurons leading to lysosomal disruption and cell death. We report here that A|fg1–42 forms slightly cation selective, voltage‐independent ion channels with multiple conductance levels at neurotoxic concentrations in planar bilayer membranes. The channels show substantial irregularity of activity, and the size of conductances and the length of open lifetimes depend on solvent history. Formation of channels requires anionic lipids, is enhanced in acidic solutions, and is inhibited by Congo Red. These properties suggest that the channels are formed by aggregates of A|fg1–42. In addition, the channels are reversibly blocked by zinc in a voltage‐independent manner. The properties of these channels would likely render them neurotoxic to relevant neurons in vivo. These results are consistent with the channel hypothesis of A|fg neurotoxicity. J. Neurosci. Res. 57:467–478, 1999. © 1999 Wiley‐Liss, Inc.