Aβ5～35 and Apo E4 enhance neuronal intracellular free Ca2+ / 中国药理学通报

ABSTRACT

AIM　To study the effects of Aβ25～35 and Apo E4 on neuronal intracellular free Ca2+(［Ca2+］i). METHODS　Hippocampal and cortical neurons suspension of newborn(0～3 days) SD rats was produced. After incubated with fura-2/AM,the neurons suspension was divided into four groups control, Aβ25～35, Apo E4, Aβ25～35+Apo E4. Each groups ［Ca2+］i was measured using a RF-5000 dual wavelength spectrofluorometer after incubated with double distilled water, Aβ25～35, Apo E4, Aβ25～35+Apo E4 for 3 min, respectively. The neurons outocorrelation function(ACF) of the scattering light intersity was analyzed by the microscope quasi-elastic light scattering(MQLS) technique The frequency shift line width by ACF. The Γ can sympolize the cell menbrane flilidity. RESULTS　Both Aβ25～35 and Apo E4 could significantly enhance hippocampal and cortical neurons rest ［Ca2+］i, furthermore, the effect of 5 μmol*L-1 Aβ25～35 was higher than the effect of 1 μmol*L-1 Aβ25～35 (P<0.05), and they also amplified KCl-induced rise in ［Ca2+］i in hippocampal and cortical neurons(P<0.05). The interaction of Aβ25～35 and Apo E4 could also significantly enhance hippocampal and cortical neurons rest ［Ca2+］i andamplified KCl-induced rise in ［Ca2+］i in hippocampal and cortical neurons(P<0.05), but they had no synergic or additive effect.The frequency shift line widith Γ of both hippocampal and cortical neurons were decreased by both Aβ25-35 and ApoE4. CONCLUSION　Aβ25～35 and Apo E4 could enhance neuronal intracellular free Ca2+, amd decrease meirpma; ,e,brame f;iodotu. But their interaction had no synergic or additive effect. It suggested that the amplified effect of Aβ25～35 and Apo E4 on neuronal ［Ca2+］i and membane fluidity may be relative to their neurotoxity.