Icariin Inhibits the Increased Inward Calcium Currents Induced by Amyloid-beta(25-35) Peptide in CA1 Pyramidal Neurons of Neonatal Rat Hippocampal Slice

Overload of intracellular calcium caused by amyloid-beta peptide has been implicated in the pathogenesis of neuronal damage in Alzheimer's disease. Voltage-gated calcium channels (VGCCs) provide one of the major sources of Ca2+ entry into cells. Here, we investigated whether icariin had effect on the changes of calcium currents induced by A beta(25-35) in hippocampal pyramidal neurons. Using whole-cell patch-clamp, we showed that A beta(25-35) enhanced the inward Ba2+ and Ca2+ currents. The currents were partially inhibited by Ni2+ and completely suppressed by Cd2+, indicating that A beta(25-35) disrupts intracellular calcium homeostasis via the modulation of both L-and T-type channels. Furthermore, icariin nearly complete suppressed the abnormal inward calcium currents induced by A beta(25-35) in a dose-dependant manner. Our findings suggest that the potential neuroprotective effect of icariin on A beta(25-35)-induced neurotoxicity via the balance intracelluar calcium homeostasis.