Change in membrane permeability induced by amyloid beta-protein fragment 25-35 in brain neurons dissociated from rats.
Effects of amyloid beta-protein fragment 25-35, A beta P(25-35), on the membrane permeability of organic molecules were examined in the brain neurons dissociated from rats by using an argon laser (equipped in flow cytometer and laser microscope) and a combination of two fluorescent dyes, fluo-3-AM and ethidium bromide. A beta P(25-35) at concentrations of 1 microM or greater induced both leakage of fluo-3 from the neurons and permeation of ethidium across the membrane in a dose-dependent manner, although both dyes are highly impermeant to the intact plasma membrane. Thus, A beta P(25-35) seems to increase not only membrane permeability of inorganic ions such as Ca2+, Na+ and K+, as previously suggested, but also that of organic molecules. Therefore, the brain neuron membrane is suggested to lose its integrity in the presence of A beta P(25-35) that leads to neuronal death.
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000814:Aniline Compounds; D000818:Animals; D001921:Brain / Q000166:cytology; D002118:Calcium / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002470:Cell Survival; D004074:Digitoxin / Q000494:pharmacology; D004996:Ethidium; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology; D007834:Lasers; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D014966:Xanthenes
D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D005456:Fluorescent Dyes; D010446:Peptide Fragments; D014966:Xanthenes; C074636:amyloid beta-protein (25-35); C059715:Fluo-3; D015759:Ionomycin; D012964:Sodium; D004074:Digitoxin; D004996:Ethidium; D011188:Potassium; D002118:Calcium