Figure 6. Ligand stimulation of 5-HT and dopamine receptors activate signaling pathways in hOE cultures.

(A) 5HT receptor function. HOE cultures were incubated with DOI, a 5-HT2 agonist, at 37°C for 5 min, in the presence of 0.5 nM [³⁵S]GTPγS. To test the role of specific subtypes in 5-HT mediated activation, the cultured cells were pre-incubated with spiperone (5-HT2A receptor antagonist), SB 204741 (5-HT2B receptor antagonist) or RS 102221 (5-HT2C receptor antagonist) for 10 min. Membrane extracts were immunoprecipitated with antibodies for Gαs/olf, -Gαi, -Gαo or -Gαq/11 and the levels of [³⁵S]GTPγS within the immunoprecipitates were measured by scintillation spectrometry. Statistical differences were analyzed using Newman-Keul's test that followed ANOVA. *p < 0.01. (B) Dopamine receptor function. HOE culture cells were pre-incubated with sch23390 or sulpiride at 37°C for 10 min, which was followed by stimulation with 1 μM dopamine and 1μM ascorbic acid, at 37°C for 5 min in the presence of 0.5 nM [³⁵S]GTPγS. Isoform specific activation of G proteins was assessed for Gαs/olf, -Gαi, -Gαo or -Gαq/11 as described for 5HT receptors in A. Statistical differences were analyzed using Newman-Keul's test that followed ANOVA. *p < 0.01.