In the last few days, it has been understood how serotonin acts on the brain. In fact, untill now, it was unclear which neurons responded to this neurotransmitter’s stimuli, nor were we able to observe the sequence of neuronal activation. The research, published in Cell Reports on 25th October 2017, may help to find new treatments against disorders of this kind of cellular signaling.
This study was conducted by two Italian research teams, guided by Alessandro Gozzi, from the Center of Neuroscience and Cognitive System in Italian Institute of Technology (CNCS-Iit based in Rovereto), and Massimo Pasqualetti, from the University of Pisa Biology departement.
An overview on the study object: serotonin
Serotonin (5-HT, 5-Hydroxytryptamine) is a tryptamine, a molecule derived from modifications of the amino acid Tryptophan. Inside the brain, serotonin is a neurotransmitter and is linked to the activity modulation of different types of neurons. It works on the control of the cerebral activities that modulate emotional sphere, sleep, body temperature and sexuality.
For these reasons, a dysfunction of this neurotransmitter causes serious damage. Not by chance, serotonin is involved in the treatment of depressive syndromes, schizophrenia and others neuropsychiatric disorders. In fact, Prozac and Dropaxin, famous anti-depressive drugs, operate on serotonin activity.
A study lasted four years
In this study, performed on lab rats, researchers used two very complexe techniques: functional Magnetic Resonance Imaging (fMRI), observing which brain areas responded first to serotonergic stimuli, and a chemogenetic technique called DREADD (designed receptors exclusively activated by designed drugs) in which they use particular drugs to make only serotonergic neurons excitable. One of the biggest problem, in fact, was the difficulty in obtaining data not linked to the activity of other types of neurons.
In this way it was possible to observe, in real time, that the action of serotonin is not distributed to all regions of the brain, but it is concentrated in particular areas.
As Professor Pasqualetti said to “La Repubblica,” a popular Italian newspaper:
Hippocampus and cerebral cortex are the areas that responded in few seconds and not by chance these are two regions involved in the regulation of the emotional behaviour; they are also the cerebral structures who show functional deficit during neuropsychiatric pathologies such as depression.
It’s clear, then, the importance of the Italian study. It will help to improve the depth comprehension of which neurons respond to serotonergic stimuli and how they do so.
Therapeutic possibilities cannot exclude knowledge of molecular, physiological, and pathophysiological mechanisms from the different system’s components: in this case, the brain.