Glutamate-dependent neuroglial calcium signaling differs between young and adult brain (Science, 2013, 339:197-200)

報告日期: 2014/05/16
報告時間: 5:10/6:00
報告學生: 鄭向帆
講評老師: 吳豐森
附件下載: 下載[1410-1396957783-1.pdf] 

Glutamate-Dependent Neuroglial Calcium signaling Differs Between Young and Adult Brain

Wei Sun,1* Evan McConnell,1* Jean-Francois Pare,2* Qiwu Xu,1* Michael Chen,1 Weiguo Peng,1 Ditte Lovatt,1 Xiaoning Han,1 Yoland Smith,2 Maiken Nedergaard1

Science 339, 197 (2013)

 

Reporter: 基醫博一鄭向帆 s58021129

Commentator: 吳豐森 Ph. D

Date: 2014/5/16

Place: Room 602

 

Abstract

Tripartite synapse has been proposed as a model that illustrates the role of astrocyte mediated in neuron synaptic transmission. The key concept of this model is the astrocyte metabotropic glutamate receptor 5 (mGluR5) dependent calcium activation in response to glutamateric transmission. However, all literatures supporting the theory were performed in young mice brain slice or culture cells, while no direct evidence is obtained from the adult in vivo model. The authors hypothesize that the mGluR5 expression patterns are different in young and adult animals. The results showed that mGluR3 was the main glutamateric receptor in the astrocytes of adult cortex and hippocampus. The electron micrographic analysis revealed that mGluR5 was barely expressed on astrocytes but abundantly expressed on post synaptic spines. In mice pup slice or young living mice model, mGluR5 agonist elicited astrocytic calcium transmission but failed to produce astrocyte activation. Despite mGluR3 was the main glutamateric receptor in the adult astrocyte, it failed to trigger calcium activation in astrocytes, suggesting that glutamate activation alone is insufficient to trigger astrocytic calcium signaling. These results suggest that the model of electrochemical transmission between neurons and astrocytes should be modified. The physiological meaning of different astrocytic transmission pattern needs to be further investigated.