Serotonin-2A receptor mRNA expression in rat retinal pigment epithelial cells.

Previous studies have shown that rat retinal pigment epithelial (RPE) cells in culture express 5-HT2-type serotonin receptors coupled to phospholipase C activity. The presented data confirm this observation where it is shown that serotonin induced increases in radioactive inositol phosphates accumulation in RPE cells pretreated with tritiated inositol. This increase was significantly (p < 0.01) attenuated by 1 microM spiperone, ketanserin, mesulergine and metergoline while the same concentration of spiroxatrine or yohimbine had no effect, suggesting the involvement of 5-HT2A receptors. Using reverse transcriptase-polymerase chain reaction the presence of 5-HT2A receptor mRNA was demonstrated in total RNA isolated from rat RPE cell cultures. Amplification of a 5-HT2A receptor mRNA-derived product was additionally confirmed by Southern blot analysis. The combined data demonstrates the existence of functional 5-HT2A receptors in rat RPE cells.