Aim and methods: Whole-cell recording technique was used to observe the changes of voltage-dependent ion channels and NMDA receptor currents of rat hippocampal neurons during primary culture.
Results: There was no significant difference of voltage-dependent Na+ current (I(Na)) at 7 d, 14 d and 21 d in culture. It's the same for delayed rectifier K+ current (Ik). However, voltage-dependent Ca2+ current (I(Ca)) and its density were continuously and markedly increased. Further studies showed that the increase of I(Ca) was resulted from the increase of L-type voltage-dependent Ca2+ channels (L-VDCC). NMDA receptor current was also significantly increased with time of culture.
Conclusion: Ca2+ influx through VDCC and NMIDA receptor is the fatal factor in the aging and death of hippocampal neurons.