HTR1A and major depressive disorder: This activity was associated with the inhibition of GABAergic neurons of the limbic pathway that express 5-HT1A, which, once activated, induces neuronal hyperpolarization, inhibiting the release of the γ-aminobutyric acid (GABA), an inhibitory neurotransmitter involved in the development of depression and mood disorders, increasing the glutamatergic influence.