Nevertheless, a possible mechanism for increased 5-HT levels in this region in HE-rats after local infusion of citalopram may be through differential activity of 5-HT1B autoreceptors, which regulate the release of 5-HT by inhibitory feedback and have been hypothesized to be supersensitive in depression and anxiety (Moreta and Briley, 2000). The gene discussed is HTR1B; the disease is major depressive disorder.