|
KMID : 0811720050090000063
|
|
Korean Journal of Physiology & Pharmacology
2005 Volume.9 No. 0 p.63 ~ p.0
|
|
|
Spatial Profile of Back-propagating Action Potential-induced Calcium Transients in Apical and Basal Dendrites
|
|
Cho Kwang-Hyun
Jang Hyun-Jong
Lee Eun-Hui
Yoon Shin-Hee
Hahn Sang-June
Jo Yang-Hyeok
Kim Myung-Suk
Rhie Duck-Joo
|
|
|
Abstract
|
|
|
Most of studies on bAP-induced calcium increase in the neocortex and the hippocampus have been focused on apical dendrites even though basal dendrites receive ～60% of total synaptic inputs in cortical pyramidal neurons. To characterize the detailed spatial profile of bAP-evoked calcium transients in basal dendrites, we measured the calcium transients evoked by somatic APs in both apical and basal dendrites of layer II/III pyramidal neurons in the visual cortex using whole-cell recording and confocal calcium imaging. Cells were loaded with a high affinity calcium indicator, Oregon Green BAPTA-1 (50μM, Kd = 170 nM). bAP-induced calcium transients were evoked by current injection into the soma in single APs or spike trains. In apical dendrites, calcium transients were increased with distance from the soma, reaching a maximum at ～80μm from the soma and then declining to undetectable levels at more distal dendrites (＞250μm from the soma). There were no differences between single APs and bursts up to 5 APs in spatial calcium profiles. Calcium signals were measured as far as 90% of entire length (～130μm) of basal dendrites. In contrast to apical dendrites, calcium transients at basal dendrites were gradually incremental with distance from the soma. The amplitude of calcium transients by bursts was larger than that by single APs in whole basal dendrites (up to 115μm). However, the calcium profile was not different between bursts and single APs. These results indicate that bAPs induce calcium transients in both apical and basal dendrites with different spatial kinetics, suggesting that the forthcoming synaptic inputs could be modulated by bAP-induced calcium increases differentially by their dendritic locations (Supported by the Neurobiology Research Program from the Korea Ministry of Science and Technology).
Source: Korean Journal of Physiology & Pharmacology.2005 Oct;9(Suppl I):S86-S86
|
|
|
KEYWORD
|
|
|
Basal dendrite, Pyramidal neuron, Synaptic input, Back-propagating AP, Confocal calcium imaging
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
  
|