Table 1

Effect of treatment of C6 glioma cells with 5-HT or ketanserin on the stimulation of IP accumulation by quipazine

Treatment	n	EC₅₀	E_max
		μM	% of control
Vehicle	6	0.51 ± 0.06
10-min 5-HT	6	0.48 ± 0.05	61 ± 4.5
2-h 5-HT	6	0.47 ± 0.10	24 ± 8.2
24-h 5-HT	6	0.48 ± 0.20	26 ± 4.4
Vehicle	4	0.54 ± 0.09
10-min ketanserin	4	0.80 ± 0.18	54 ± 4.2
30-min ketanserin	4	0.83 ± 0.18	63 ± 5.6
2-h ketanserin	4	0.55 ± 0.08	66 ± 6.9

Cells were treated with 5-HT (10 μM) and ketanserin (50 nM) for indicated times. Accumulation of [³H]IP was measured in triplicate after a 20-min incubation with quipazine, as described in Fig. 1. Shown are the mean ± S.E.M. EC₅₀ values were analyzed by analysis of variance.