Table 1.

Summary of signaling and pharmacological reagents for proton-sensitive channels and GPCRs.

Gene	Location and accession number	Ion selectivity or signaling	Agonist (EC50)	Antagonist (IC50)	Modulator	References for pharmacological reagents
ASIC1	Human: 12q13.12NM_001095.4 (ASIC1a) HM991481 (ASIC1b)	Na+/Ca2+	MitTx: ASIC1a (9.4 nM) ASIC1b (23 nM)	PcTx1 (1 nM) Mambalgin ASIC1a (55 nM) Hi1aDiminazene AmilorideA-317567	Big dynorphin & dynaorphin A (EC50 ∼30 µM) Spermine	120–124 125,126
	Mouse: chr 15NM_009597.2 (ASIC1a) NM_001289791 (ASIC1b)
	Identity: ASIC1a 97.9% ASIC1b 93.8%
ASIC2	Human: 17q11.2-q12NM_001094 (ASIC2a) NM_183377.2 (ASIC2b)	Na+		Diminazene Amiloride	Zn2+	125 , 127
	Mouse: chr 11NM_001034013 (ASIC2a) NM_007384 (ASIC2b)
	Identity: ASIC2a 99.2% ASIC2b 97.2%
ASIC3	Human: 7q36.1NM_004769.4	Na+	MitTx (830 nM)	APETx2 (63 nM) AmilorideA-317567	GMQ (67 µM) Neuropeptide SF (50 µM) lactate	126,128–130
	Mouse: chr 5 NM_183000.2
	Identity: 83.3%
PAC/ASOR	Human: 1q32.3NM_001198862.2	Cl−		pregnenolone sulfate		11
	Mouse: chr 1 NM_025864.4
	Identity: 90.3%
GPR4	Human: 19q13.32NM_005282	GsG12/13Gqpossibly Gi		Compound 3b (67 nM) NE 52-QQ 57 (70 nM hGPR4; 1.8 µM rGPR4)		84 , 131
	Mouse: Chr 7NM_175668
	Identity: 91.5%
GPR65 (TDAG8)	Human: 14q31.3NM_003608	Gs			ZINC13684400 (positive) ZINC62678696 (negative)	106
	Mouse: chr 12 NM_008152.3
	Identity: 78.5%
GPR68 (OGR1)	Human: 14q32.11NM_003485	Gq, Gspossibly Giand G12/13	CARTPT (76–96) 3.2 µMOsteocrin (115–133) 0.4 µMCorticotropin (17–40) 1.8 µM	Cu2+ (µM range) Zn2+ (µM range)	Ogerin (positive modulator for Gs pathway) Lorazepam (non-specific) MS48107	72 , 106 , 132
	Mouse: Chr 12NM_175493
	Identity: 92.1%

CARTPT: cocaine- and amphetamine-regulated protein; GMQ: 2-guanidine-4-methylquinazoline; PcTx1: psalmotoxin 1.