L-type calcium channels mediate synchronized spontaneous Ca2+spikes in cultured cortical networks.
We have detected synchronized spontaneous Ca2+spikes in cultured cortical networks in the presence of Mg2+. The synchronized spontaneous Ca2+spikes are synaptically driven, as it is blocked by tetrodotoxin (TTX), and by the glutamate receptor antagonist CNQX/APV. The oscillatory activity is not influenced by GABA<inf>A</inf>receptor antagonist picrotoxin, suggesting that they entirely rely on glutamatergic neurotransmission. We have also found that these Ca2+spikes are dependent on an influx of extracellular Ca2+but are independent of mobilization of Ca2+from intracellular Ca2+stores. Ca2+entry occurred primarily through L-type voltage-gated calcium channels (VGCCs), since nifedipine completely blocked these Ca2+spikes.
He
Jun
J
Key Laboratory of Biomedical Photonics of Ministry of Education, Huazhong University of Science and Technology, Wuhan 430074, P.R. China (e-mail: hjytzx@163.com).
Zhou
Wei
W
Zeng
Shaoqun
S
Luo
Qingming
Q