Effect of Ab_(1-40) on membrane permeability and intracellular free Ca~(2+) of nerve cells

Alzheimers disease (AD) is a kind of progressive neurodegenerative disease, characterized by intracellularfibrillar tangles and extracellular senile plaques, the main component of the plaques are b-amyloid (Ab), composed of 3943 amino acids1]. Glenner and Wong first isolated Ab peptide and determined the sequence in 1984, after-wards, a series of researches were done on its production, structure determination, aggregation, hydrophobicity, re-ceptor and cell toxicity. Ab is the abnormal fiss…

Effect of Ab_(1-40) on membrane permeability and intracellular free Ca~(2+) of nerve cells

The effects of soluble and fibrillar Ab1-40 on membrane permeability and intracellular free Ca2+ of nerve cells were investigated by the laser confocal microscopy. Results indicate that: i) Effects of soluble and fibrillar Ab1-40 on cell membrane permeability are both concentration-de- pendent. Soluble Ab1-40 increases membrane permeability only at concentration of 3 mmol/L, while the toxic effect of fibrillar Ab1-40 is much stronger, its evident effect begins from 1 mmol/L. When its concentration rose to 3 mmol/L, not only the membrane permeability increased, but also the nuclear membrane broke seriously. ii) Both soluble and fibrillar Ab1-40 at high concentrations increased the intracellular free Ca2+, and the increased amplitudes are concentration-dependent. However, the fibrillar one induces the increase of intracellular Ca2+ much quicker and synchronously. These results indicate that some correlation exists between the neurotoxicity of high concentration soluble and fibrillar Ab1-40 and the change of physico-chemical properties and intracellular Ca ion imbalance.