The authors suggest this could be due to the drug - use causing progressive damage
of serotonin neurons.
Prostaglandin signaling
in serotonin neurons was not required for aversive responses to high temperatures, suggesting that this pain - aversive signaling pathway is specific to inflammatory pain.
To better understand the link between GABA and the development of stress resilience, Berton, Beck, and colleagues also devised an optogenetics - based approach to directly manipulate levels: Lifting GABA inhibition of
serotonin neurons reduced social and anxiety symptoms in mice exposed to bullies and also fully prevented neurobiological changes due to stress.
People think of serotonin as related to happiness, but
serotonin neurons appear to send a message that is not good or bad but more «oops» or surprise — my old expectations are not right any more.
As serotonin neuron axons branch out through the brain, they can recognize other axons carrying identical IDs and spread out to keep out of each other's paths.
Further experiments showed that
descending serotonin neurons, coming from the brain and spinal cord, contact a type of neuron that expresses gastrin - dependent peptide receptors.
In this study, Xu and colleagues identified a neural circuit where a group of
serotonin neurons project to and activate dopamine neurons.
«This work reveals how
diverse serotonin neurons are at the molecular level, which may help to explain how, collectively, they are able to perform so many distinct functions,» said Benjamin Okaty, a postdoctoral researcher in the Dymecki lab and co-first author of the paper.
42: Politis M, Wu K, Loane C, Quinn NP, Brooks DJ, Oertel WH, Björklund A, Lindvall O, Piccini
P. Serotonin neuron loss and nonmotor symptoms continue in Parkinson's patients treated with dopamine grafts.
To better understand the link between GABA and the development of stress resilience, Berton, Beck, and colleagues also devised an approach to directly manipulate levels: Lifting GABA inhibition
of serotonin neurons reduced social and anxiety symptoms in mice exposed to bullies and also fully prevented neurobiological changes due to stress.
«When
the serotonin neuron is turned on, the worm is active and wants to do a specific behavior, such as locomotion or lays its eggs.
The idea for Smith's study was inspired by the work of co-author Alena Savonenko, M.D., Ph.D., associate professor of pathology, and her colleagues who showed that loss of
serotonin neurons was associated with more protein clumps, or amyloid, in mouse brain.
Previous studies from Johns Hopkins and other centers have shown that people with Alzheimer's disease and severe cognitive decline have severe loss of
serotonin neurons, but the studies did not show whether those reductions were a cause or effect of the disease.
Normally, as people age,
the serotonin neurons are especially vulnerable to neurodegeneration, so the transporters are lost when these neurons die and serotonin levels go down.
Of those two, only the protein coded by the Pcdhαc2 gene was found in
the serotonin neurons.