Influence of receptor antagonists and selective serotonin reuptake inhibitors on 5-HT actions against group 1 BL cells.

(A) L3055 cells were pretreated for 30 minutes with the 5-HT receptor antagonists (SDZ205-557 [10 μM], granisetron [1 μM], methysergide [1 μM]), alone or in combination, before the addition of 125 μM 5-HT (+ 5-HT) or control medium (control), and DNA synthesis was assessed as in Figure 1A. (B) As for panel A, but cells were cultured with 150 μM 5-HT alone (0; striped bar) or with 5-HT after 30-minute pretreatment with the SSRI, fluoxetine (black bars), citalopram (white bars), or paroxetine (gray bars) at concentrations indicated. Results are expressed as % control (no addition) values. Data are represented as the mean ± SEM of 3 (A) or 4 (B) separate experiments.