Calcium action potentials restricted to distal apical dendrites of rat neocortical pyramidal neurons

被引:361
作者
Schiller, J [1 ]
Schiller, Y [1 ]
Stuart, G [1 ]
Sakmann, B [1 ]
机构
[1] Max Planck Inst Med Forsch, Zellphysiol Abt, D-69120 Heidelberg, Germany
来源
JOURNAL OF PHYSIOLOGY-LONDON | 1997年 / 505卷 / 03期
关键词
D O I
10.1111/j.1469-7793.1997.605ba.x
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
1. Simultaneous whole-cell voltage and Ca2+ fluorescence measurements were made from the distal epical dendrites and the soma of thick tufted pyramidal neurons in layer 5 of 4-week-old (P28-32) rat neocortex slices to investigate whether activation of distal synaptic inputs can initiate regenerative responses in dendrites. 2. Dual whole-cell voltage recordings from the distal apical trunk and primary tuft branches (540-940 pm distal to the soma) showed that distal synaptic stimulation (upper layer 2) evoking a subthreshold depolarization at the soma could initiate regenerative potentials in distal branches of the apical tuft which were either graded or all-or-none. These regenerative potentials did not propagate actively to the soma and axon. 3. Calcium fluorescence measurements along the apical dendrites indicated that the regenerative potentials were associated with a transient increase in the concentration of intracellular free calcium ([Ca2+](i)) restricted to distal dendrites. 4. Cadmium added to the bath solution blocked both the all-or-none dendritic regenerative potentials and local dendritic [Ca2+](i) transients evoked by distal dendritic current injection. Thus, the regenerative potentials in distal dendrites represent local Ca2+ action potentials. 5. Initiation of distal Ca2+ action potentials by a synaptic stimulus required coactivation of AMPA-and NMDA-type glutamate receptor channels. 6. It is concluded that in neocortical layer 5 pyramidal neurons of P28-32 animals glutamatergic synaptic inputs to the distal apical dendrites can be amplified via local Ca2+ action potentials which do not reach threshold for axonal AP initiation. As amplification of distal excitatory synaptic input is associated with a localized increase in [Ca2+](i) these Ca2+ action potentials could control the synaptic efficacy of the distal cortico-cortical inputs to layer 5 pyramidal neurons.
引用
收藏
页码:605 / 616
页数:12
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