Table 2.

Effect of ZK200775 on evoked potentials in rat cortical slice preparations and spreading depression in chicken retina

	Quisqualate	Kainate	NMDA	Glycine
Evoked potentials (EP) Ki, μM	0.0032	0.1	8.5	-
Spreading depression (SD)	0.2	0.076	13	18
IC50, μM	(0.05–0.90)	(0.015–0.379)	(7–23)	(6.68–48.25)

EP: Agonists were applied to rat (Wistar; Møllegaard) cingulate cortex slices in concentrations of 3–100 μM for quisqualate, 0.5–5 μM for kainate, and 5–40 μM for NMDA for 2 min, and the evoked potentials were recorded. K_i values represent concentrations of ZK200775, which produced a two-fold shift to the right of the agonist concentration–response curves and were calculated using linear regression analysis. SD: The posterior chamber of each chicken (3 to 6-day-old, Copenhagen Serum Institute, Denmark) eye was placed in O₂ saturated saline containing quisqualate (5 μM), kainate (5 μM), NMDA (100 μM), or glycine (100 μM) alone or with different concentrations of ZK200775 ranging from 0.25 to 75 μM. The occurrence of a white area (0.5 mm in diameter) was taken as the onset of spreading depression, and the latency to it was measured. Cut-off time was set at 60 s. An increase in the latency by 30 s was considered to represent maximal inhibition of spreading depression. The drug effects were expressed as the percentage of maximum inhibition at a given concentration. IC₅₀ values were calculated by means of linear regression analysis.