Researchers at Karolinska Institutet have now traced the brain's lower plasticity to reduced functionality in its support cells, and believe that learning more about these cells can pave the way for radical new therapies for depression.
"We were able to cure memory dysfunction in 'depressed' rats by giving them doses of D-serine," says Mia Lindskog, biologist and Assistant Professor at Karolinska Institutet's Department of Neuroscience.
Dr Lindskog and her team used FSL rats, which are rats that have been specially bred with a disposition for 'depression'. The rats were first put through two tests to confirm that they had the symptoms that are also characteristic of human depression. In the first, the rats' memories were checked by repeatedly being exposed to different objects; in the second, the team assessed their level of apathy by releasing them in a container of water and observing whether they merely stayed floating in the container or immediately tried to climb out (non of the rats had to stay in the water for more than five minutes). In both cases the FSL rats' results were compared with normal laboratory rats, and memory disorders and apathy could be confirmed.
The researchers then injected the rats with D-serine. This substance improved their memories but had no effect on the apathy.
"We have shown that there are two symptoms here that can be influenced independently of one another, which means they could be treated in tandem in patients with depression," says Dr Lindskog.
The researchers also studied the synaptic activity in the hippocampus of the rats, a part of the brain which plays an important part in the memory. They found that there was a much higher degree of synaptic activity in the brains of the depressed rats than in the controls. However, when the researchers tried to increase the level of signal transmission, they found the brains of the depressed rats to be unresponsive, which indicated that they had a lower plasticity that rendered them unable to increase neuronal activity when needed - unlike the brains of the healthy rats. When the brain samples were soaked in D-serine, the plasticity of the depressed rats' brains improved.
D-serine is a substance secreted by astrocytes, which are support cells for brain neurons.
"We don't actually know very much about these glial cells, but it's very likely that they perform a very important function in the brain," says Dr Lindskog.
It is hoped that their discoveries will eventually lead to new therapies for depression.
"D-serine doesn't pass the blood-brain barrier particularly well, so it's not really a suitable candidate on which to base a drug, but the mechanism that we've identified, whereby it's possible to increase plasticity and improve the memory, is a feasible route that we might be able to reach in a way that doesn't involve D-serine," says Dr Lindskog.
Marta Gómez-Galán, Dimitri De Bundel, Ann Van Eeckhaut, Ilse Smolders & Maria Lindskog
Dysfunctional Astrocytic Regulation of Glutamate Transmission in a Rat Model of Depression
Molecular Psychiatry, online 28 February 2012For further information, please contact:
Katarina Sternudd | EurekAlert!
Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital
Highly precise wiring in the Cerebral Cortex
21.09.2017 | Max-Planck-Institut für Hirnforschung
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
21.09.2017 | Physics and Astronomy
21.09.2017 | Life Sciences
21.09.2017 | Health and Medicine