Table 2.

Electrophysiological activity of sea anemone toxins of structural class 1b on homomeric acid-sensing ion channels (ASICs).

Peptide	ASIC1a	ASIC3
APETx2	-	↓ IC50 0.063 μM	[32]
		↓ IC50 0.175 μM *
Hcr 1b-1	no data	↓ IC50 5.5 ± 1.0 μM *	[24]
Hcr 1b-2	↓ IC50 4.8 ± 0.3 μM	↓ IC50 15.9 ± 1.1 μM	[25]
Hcr 1b-3	↓ IC50 4.95 ± 0.19 μM	↓ IC50 17 ± 5.8 μM	this work
Hcr 1b-4	↓ IC50 1.25 ± 0.04 μM	↑ EC50 1.53 ± 0.07 μM	this work

* IC₅₀ values for APETx2 and Hcr 1b-1 were obtained toward human ASIC3 expressed in simian-kidney-derived COS-7 cells [32] and X. laevis oocytes [24], respectively. All other electrophysiological experiments were performed with rat ASIC1a and ASIC3 channels expressed in X. laevis oocytes. Inhibitory and potentiating effects are shown as ↓ and ↑, respectively.