HTR1A and Anxiety: 5-HT1A receptors (mainly in raphe nuclei, and the hippocampus, cortex and limbic system) have been implicated in behavior and emotion and their modulatory role in anxiety-related behaviors is supported from studies with 5-HT1A receptor knockout mice (exhibiting anxiety-like behavior)60,61 and transgenic mice overexpressing 5-HT1A receptors (demonstrating decreased anxiety-like behavior)62.