Ca(2+) Signaling in Astrocytes from Ip3r2(-/-) Mice in Brain Slices and During Startle Responses in Vivo

Overview

Journal Nat Neurosci

Date 2015 Apr 21

PMID 25894291

Citations 247

Authors

Rahul Srinivasan

Ben S Huang

Sharmila Venugopal

April D Johnston

Hua Chai

Hongkui Zeng

Peyman Golshani

Baljit S Khakh

Affiliations

Soon will be listed here.

Abstract

Intracellular Ca(2+) signaling is considered to be important for multiple astrocyte functions in neural circuits. However, mice devoid of inositol triphosphate type 2 receptors (IP3R2) reportedly lack all astrocyte Ca(2+) signaling, but display no neuronal or neurovascular deficits, implying that astrocyte Ca(2+) fluctuations are not involved in these functions. An assumption has been that the loss of somatic Ca(2+) fluctuations also reflects a similar loss in astrocyte processes. We tested this assumption and found diverse types of Ca(2+) fluctuations in astrocytes, with most occurring in processes rather than in somata. These fluctuations were preserved in Ip3r2(-/-) (also known as Itpr2(-/-)) mice in brain slices and in vivo, occurred in end feet, and were increased by G protein-coupled receptor activation and by startle-induced neuromodulatory responses. Our data reveal previously unknown Ca(2+) fluctuations in astrocytes and highlight limitations of studies that used Ip3r2(-/-) mice to evaluate astrocyte contributions to neural circuit function and mouse behavior.

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