Table 2

Correlation between synaptosomal and EAAT pharmacology

Compound	Synaptosomes		EAAT 1		EAAT 2		EAAT 3
Compound	K_i	efflux	K_m	I_max	K_morK_i^*	I_max	K_m	I_max
	μM	% of Glu	μM	% of Glu	μM	% of Glu	μM	% of Glu
l-Glutamate	4.9 ± 1	100	20 ± 3	100	18 ± 3	100	28 ± 6	100
DHK	28 ± 2	3.0 ± 1.5	n.d.	n.d.	9^*	0	n.d.	n.d.
l-trans-2,3-PDC	33 ± 6	5.0 ± 1.5	n.d.	n.d.	12^*	0	n.d.	n.d.
2,4-MPDC	6.8 ± 3	82 ± 9	87 ± 7	40 ± 4	45 ± 3	115 ± 3	85 ± 10	54 ± 2

Analogs were evaluated as inhibitors and substrates in oocytes expressing EAAT1, EAAT2, and EAAT3. In the instances where compounds exhibited no substrate activity (^*), K _i values were calculated by Schild analysis. In the heteroexchange studies, analogs were tested at concentrations ≈ 10 × greater than theK _i values for inhibition of d-aspartate uptake. Values indicating substrate activity are reported as a percentage of the activity of l-glutamate at 37°C.

n.d., not detected.