For people with depression, gastrointestinal distress is a common additional burden, and a new study suggests that for some, the two conditions arise from the same glitch in neuron chemistry — low serotonin.
The study, conducted in mice, shows that a shortage of serotonin in the neurons of the gut can cause constipation, just as a serotonin shortage in the brain can lead to depression.
The study also found that a treatment that raises serotonin in the gut and the brain may alleviate both conditions.
Up to a third of people with depression have chronic constipation, and a few studies report that people with depression rate their accompanying bowel difficulties as one of the biggest factors reducing their quality of life.
Full story at Science Daily
L-5 hydroxytryptophan is a natural chemical in the body that people can also take as a nutritional supplement. Some people believe that taking the supplement can improve certain aspects of health, including mental health and sleep quality.
The compound is a natural precursor to a neurotransmitter called serotonin, which helps produce “feel-good” chemicals in the brain and body.
However, there is little significant research to prove that L-5 hydroxytryptophan (5-HTP) can offer such benefits.
Full story at Medical News Today
A new area in depression research suggests dysfunction in mitochondria — the main source of energy for cells — could lead to major depression. Published in Frontiers in Neuroscience, this new insight to long-held theories on the causes of depression could lead to the development of novel and more effective antidepressant drugs.
Depression is a highly prevalent disorder affecting up to 20% of the population. It is commonly thought to be caused by a chemical imbalance in the brain, yet the specific biological mechanisms which lead to depression are not fully understood.
“Until now, most theories about the biological causes of depression have focused on the idea that depression is caused by an imbalance in neurotransmitters like serotonin,” says Dr Lisa E. Kalynchuk, co-author of the review from the University of Victoria, Canada.
Full story at Science Daily
NIH-funded scientists revealed the types of neurons supporting alertness, using a molecular method called MultiMAP in transparent larval zebrafish. Multiple types of neurons communicate by secreting the same major chemical messengers: serotonin (red), dopamine and noradrenaline (yellow) and acetylcholine (cyan).
Source: Karl Deisseroth, M.D., Ph.D., Stanford University
Using a molecular method likely to become widely adopted by the field, researchers supported by the National Institutes of Health have discovered brain circuitry essential for alertness, or vigilance – and for brain states more generally. Strikingly, the same cell types and circuits are engaged during alertness in zebra fish and mice, species whose evolutionary forebears parted ways hundreds of millions of years ago. This suggests that the human brain is likely similarly wired for this state critical to survival.
“Vigilance gone awry marks states such as mania and those seen in post-traumatic stress disorder and depression,” explained Joshua Gordon, M.D., Ph.D., director of the NIH’s National Institute of Mental Health (NIMH), which along with the National Institute on Drug Abuse, co-funded the study. “Gaining familiarity with the molecular players in a behavior – as this new tool promises – may someday lead to clinical interventions targeting dysfunctional brain states.”
Full story at NIHM
Millions of people suffer from the constant sensation of ringing or buzzing in the ears known as tinnitus, creating constant irritation for some and severe anxiety for others. Research by scientists at OHSU shows why a common antidepressant medication may worsen the condition.
The study, to be published Aug. 22 in the journal Cell Reports, focused on the action of serotonin, an important neuromodulator in the brain. Researchers examined brain tissue in mice, specifically the dorsal cochlear nucleus where sensory integration and tinnitus occurs. Researchers discovered that neurons known as fusiform cells within this portion of the brain become hyperactive and hypersensitive to stimuli when exposed to serotonin.
Full story at Science Daily
Depression and anxiety disorders are the most common psychiatric disorders. Over the last few years, molecular brain imaging using Positron Emission Tomography (PET) has helped us to identify important mechanisms involved in the development and treatment of these disorders, particularly those associated with the serotonin neurotransmitter system. The drugs that are used for these conditions (SSRIs) were developed 30 years ago. To celebrate this anniversary, a team from MedUni Vienna, led by Siegfried Kasper, Director of the University Department of Psychiatry and Psychotherapy, has summarised the latest status of global research in this field in The Lancet Psychiatry.
“People laughed at us when we started treating depression with SSRIs (selective serotonin reuptake inhibitors) 30 years ago,” explains Siegfried Kasper, who is also one of the pioneers of this method of treatment. “Today it is State of the Art and we are able to quantify disturbances in serotonin signal transmission in the brain as the cause of depression and anxiety disorders.” 80% of those suffering from depression are treated with SSRIs — the success rate is around 70%. Kasper: “Their quality of life is enhanced and there is a significant and lasting improvement in their motivation and mood.”
Full story of depression and serotonin signal disturbances at Science Daily
About 15 percent of women in the United States suffer from anxiety disorders and depression during their pregnancies, and many are prescribed antidepressants. However little is known about how early exposure to these medications might affect their offspring as they mature into adults.
The answer to that question is vital, as 5 percent of all babies born in the U.S. — more than 200,000 a year — are exposed to antidepressants during gestation via transmission from their mothers.
Now, a UCLA team has studied early developmental exposure to two different antidepressants, Prozac and Lexapro, in a mouse model that mimics human third trimester medication exposure. They found that, although these serotonin-selective reuptake inhibiting antidepressants (SSRIs) were thought to work the same way, they did not produce the same long-term changes in anxiety behavior in the adult mice.
Full story of antidepressants for adult anxiety at Science Daily
A lot of research has shown that poor regulation of the serotonin system, caused by certain genetic variations, can increase the risk of developing psychiatric illnesses such as autism, depression, or anxiety disorders. Furthermore, genetic variations in the components of the serotonin system can interact with stress experienced during the fetal stages and/or early childhood, which can also increase the risk of developing psychiatric problems later on.
In order to better understand serotonin’s influence in the developing brain, Alexandre Dayer’s team in the Psychiatry and Fundamental Neuroscience Departments of UNIGE’s Faculty of medicine examined a particular receptor for this neurotransmitter, and its role in the formation of brain circuits. The researchers were able to show that this receptor, which is expressed in inhibitory interneurons (cells that regulate excitement in order to avoid potentially pathological cerebral over activity), was indispensable in order for neurons to find their correct location in the developing cortex.
Full story on serotonin’s role in brain circuits at Science Daily