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 accumul ation in RPE cells pretreated with tritiated inositol. This increase was si gnificantly (p < 0.01) attenuated by 1 mu M spiperone, ketanserin, mesulerg ine and metergoline while the same concentration of spiroxatrine or yohimbi ne had no effect, suggesting the involvement of 5-HT2A receptors. Using rev erse transcriptase-polymerase chain reaction the presence of 5-HT2A recepto r mRNA was demonstrated in total RNA isolated from rat RPE cell cultures. A mplification of a 5-HT2A receptor mRNA-derived product was additionally con firmed by Southern blot analysis. The combined data demonstrates the existe nce of functional 5-HT2A receptors in rat RPE cells.