Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
J Physiol. 2010 Apr 15;588(Pt 8):1281-92. doi: 10.1113/jphysiol.2009.185645. Epub 2010 Mar 1.
Synaptic activity in the medial prefrontal cortex (mPFC) is fundamental for higher cognitive functions such as working memory. The present study shows that small conductance (SK) calcium-activated potassium channels attenuate excitatory synaptic transmission at layer 2/3 and layer 5 inputs to layer 5 pyramidal neurons in the mPFC. SK channels are located postsynaptically at synapses where they are activated during synaptic transmission by calcium influx through NMDA receptors, L-type calcium channels, R-type calcium channels and by calcium release from IP(3)-sensitive stores. Removal of the SK channel-mediated shunt of synaptic transmission reveals significant NMDA receptor-mediated activation during basal synaptic transmission, which is greater at layer 5 inputs (approximately 30%) than at layer 2/3 inputs (approximately 20%). These findings show that interactions between NMDA receptors, SK channels and voltage-gated calcium channels play a critical role in regulating excitatory synaptic transmission in layer 5 pyramidal neurons in the mPFC.
前额叶皮质（mPFC）中的突触活动对于工作记忆等高级认知功能至关重要。本研究表明，小电导（SK）钙激活钾通道可减弱 mPFC 中第 2/3 层和第 5 层输入到第 5 层锥体神经元的兴奋性突触传递。SK 通道位于突触后，在突触处，它们通过 NMDA 受体、L 型钙通道、R 型钙通道内流的钙以及 IP3 敏感储存器内的钙释放而在突触传递过程中被激活。去除 SK 通道介导的突触传递分流会揭示基础突触传递过程中 NMDA 受体介导的显著激活，而在第 5 层输入（约 30%）中比在第 2/3 层输入（约 20%）中更为明显。这些发现表明，NMDA 受体、SK 通道和电压门控钙通道之间的相互作用在调节 mPFC 中第 5 层锥体神经元的兴奋性突触传递中起着关键作用。
