Tryptophan and Membrane Mobility as Conditioners and Brokers of Gut–Brain Axis in Depression

The aim of this brief narrative commentary is to discuss some aspects involved in depression. It is increasingly evident that the phenomenon of mood disorders, despite its unequivocal genetic origin, slips into a multifactorial set of biochemical and molecular events that involve the whole organism. A vast literature has provided evidence that recognizes changes in serotonergic neurotransmission in the pathophysiology of depression. In addition, an increased arachidonic acid/omega-3 fatty acid ratio, which confers to mammalian cell membranes their fluidity, is associated with the depressive state. The combination of the excessive expression of kinurenine and the increased fluidity of the membrane has never been considered in the meaning of a simultaneous eect in the determinism of the depressive condition. Furthermore, various evidence supports the relationship between intestinal microbiota and depression and confirms alterations in the microbiota in depressive pathology.