TABLE 1.

Genetically encoded indicators for measuring astrocyte function^a

Available indicators for readout of neuron-astrocyte signaling
Indicator type	Indicator name(s)	Available color variants	References
Acetylcholine	iAChSnFR, GRABACh	Green	Borden et al., 2020; Jing et al., 2020
Adenosine	GRABAdo	Green	Peng et al., 2020
ATP	iATPSnFR, GRABATP	Green	Lobas et al., 2019; Wu, He, et al., 2021
Dopamine	dLight, GRABDA	Green, yellow, red	Patriarchi et al., 2018; Patriarchi et al., 2020; Sun et al., 2018
D-Serine	D-serFSb	Cyan-yellowb	Vongsouthi et al., 2021
Endocannabinoid	GRABeCB	Green	Dong, He, et al., 2021
GABA	iGABASnFR	Green	Marvin et al., 2019
Glutamate	iGluSnFR	Blue, cyan, green, yellow	Marvin et al., 2018
Glycine	GlyFSb	Cyan-yellowb	Zhang et al., 2018
Nicotine	iNicSnFR	Green	Shivange et al., 2019
Norepinephrine	nLight, GRABNE	Green	Feng et al., 2019; Oe et al., 2020
Serotonin	sLight, iSeroSnFR, GRAB5–HT	Green	Patriarchi et al., 2018; Unger et al., 2020; Wan et al., 2021
Available indicators for readout of intracellular signaling
ATP/ADP	Perceval	Green	Berg et al., 2009
ATP	ATeamsb	Cyan-yellowb	Imamura et al., 2009
Calcium	X-CaMP series, X-GECO series	Blue, green, yellow, red, near-infrared	Dalangin et al., 2020; Dana et al., 2016; Dana et al., 2019; Inoue et al., 2019; Qian et al., 2020; Shemetov et al., 2021; Shen et al., 2018
cAMP	Flamindo series, R-FlincA, cAMPr	Yellow, red	Hackley et al., 2018; Harada et al., 2017; Kim, Shin, & Bae, 2021; Odaka et al., 2014; Ohta et al., 2018
Chloride	SuperClomeleonb, ClopHensorNb	Cyan-yellowb, green-redb	Grimley et al., 2013; Raimondo et al., 2013
ERK	RAB-EKARevb	Green-redb	Ding et al., 2015
Glucose	iGlucoSnFR, FLIPglub, Green Glifons	Green, cyan-yellowb	Díaz-García et al., 2019; Fehr et al., 2003; Keller et al., 2021; Mita et al., 2019
IP3	IRIS-1b	Cyan-yellowb	Matsu-ura et al., 2006
Lactate	eLACCO, Laconicb	Green, cyan-yellowb	Nasu et al., 2021; San Martín et al., 2013
NADH/NAD+	Peredoxb	Green-redb	Hung et al., 2011
NADPH	iNapb	Cyan-yellowb	Tao et al., 2017
pH	pHRedb, ClopHensorNb	Red, green-redb	Raimondo et al., 2013; Tantama et al., 2011
PKA	ExRai-AKAR	Green	Zhang et al., 2021
Potassium (K+)	GEPIIb, KIRINb, GINKO2, KRaION	Cyan-yellowb, green-redb, green	Bischof et al., 2017; Torres Cabán et al., 2021; Wu, Wen, et al., 2021
ROS (H2O2)	FROG/Bb, HyPer7b, HyPerRed	Blue-greenb, greenb, red	Ermakova et al., 2014; Pak et al., 2020; Sugiura et al., 2020
Available indicators for readout of astrocyte-neuron signaling
ATP, GABA, glutamate, etc. See above		See above	See above

Abbreviations: cAMP, cyclic adenosine monophosphate; cGMP, cyclic guanosine monophosphate; IP₃, inositol-trisphosphate; PKA, protein kinase A; ROS, reactive oxygen species.

^aThis table does not cover existing synthetic indicators (e.g., CoroNa Green AM for sodium), which may be helpful in acute experiments. For additional genetically encoded indicators (e.g., for cAMP), see the cited reviews. For an overview of additional genetically encoded metabolite sensors, see Koveal et al., 2020; San Martin et al., 2014; Zhang et al., 2020; San Martin et al., 2022.

^bRatiometric indicator.