HTR1A and major depressive disorder: To investigate whether the impairment of cholesterol biosynthesis and thus the resulting changes in cellular cholesterol content have an effect on the functionality of receptors known to be involved in depression, the effect of simvastatin, water soluble cholesterol, and Ze 117 on β-arrestin 2 recruitment after 5-HT1A-receptor stimulation with serotonin was tested in transiently transfected HEK 293 cells.