TABLE 14.

IC₅₀ values in micromolar for uncompetitive AMPA receptor antagonists

All data from GluA2 are from the edited form [GluA2(R)].

Uncompetitive Antagonist	GluA1	GluA2	GluA3	GluA4	GluA1/GluA2
	μM
Argiotoxin 636	0.35–3.4a,b	N.E.a	0.23a	0.43a	300b
Joro spider toxin	0.04c	N.E.c	0.03c		N.E.c
Philanthotoxin 433d			0.8		N.E.
Philanthotoxin 343	2.8b				270b
Philanthotoxin 56	3.3 pMe				5.2e
Philanthotoxin 74	0.17e				1.6e
IEM-1460	1.6f	N.E.g	1.6f
IEM-1754	6.0f		6.0f
HPP-spermined	0.5		0.08	0.5	N.E.

HPP-spermine, N-(4-hydroxyphenylpropanoyl)spermine trihydrochloride; IEM-1754, 1-ammonio-5-(1-adamantane-methylammoniopentane dibromide); N.E., no effect.

^a Herlitze et al. (1993); holding membrane potential was −70 mV.

^b Brackley et al. (1993); holding membrane potential, −80 mV.

^c Blaschke et al. (1993); holding membrane potential, −100 mV.

^d Washburn and Dingledine (1996); holding membrane potential, −70 mV. Although IC₅₀ values were not calculated, initial experiments suggested that philanthotoxin-433 had a lower affinity for GluA1 and GluA4 receptors compared with GluA3.

^e Philanthotoxin 56 has an IC₅₀ of 3.3 pM for recombinant GluA1 (Kromann et al., 2002); holding membrane potential, −80 mV.

^f Magazanik et al. (1997); holding membrane potential, −80 mV.

^g Schlesinger et al. (2005); holding membrane potential, −60 mV, recombinant human GluA2(R).