In fact, in animal models of depression cortisol has been shown to negatively regulate the 5-HT1A receptor in a dose-dependent manner [256], and other research has shown in lymphocytes from MDD patients a decrease in the density of the 5-HT transporter [23] and inhibition of 5-HT1A receptor function [22]. The gene discussed is HTR1A; the disease is major depressive disorder.