Individual receptor variants lead to especially long and branched processes called dendrites, which the cells communicate with. The researchers also showed that the growth-promoting property of the receptors is linked to how much calcium they allow to flow into the cells. “These results allow insights into the mechanisms with which nerve cells connect during development”, says Prof. Dr. Petra Wahle from the RUB Working Group on Developmental Neurobiology. The scientists report in Development.
Growth of dendritic processes: When glutamate docks on to the AMPA receptor, calcium ions flow into the nerve cell. They cause the production of special growth molecules which trigger the extension and branching of the dendrites. AG Entwicklungsneurobiologie
Effect of a glutamate receptor: The researchers compared the architecture of special inhibitory nerve cells (interneurons) with low and high numbers of a specific glutamate receptor (GluA1(Q)-flip). Cells with a high number of GluA1(Q)-flip (right) had longer and more branched dendritic processes than cells in which the receptor only occurred rarely (left). AG Entwicklungsneurobiologie
It all depends on a few amino acids
“Nerve cells communicate with chemical and electrical signals”, explains Wahle. “The electrical activity controls many developmental processes in the brain, and the neurotransmitter glutamate plays a decisive role in this.” In two different cell classes in the cerebral cortex of rats, the researchers studied the nine most common variants of a glutamate receptor, the so-called AMPA receptor. When glutamate docks on to this receptor, calcium ions flow into the nerve cells either directly through a pore in the AMPA receptor or through adjacent calcium channels. Depending on the variant, AMPA receptors consist of 800-900 amino acid building blocks, and already the exchange of one amino acid has important consequences for the calcium permeability. Among other things, calcium promotes the growth of new dendrites.
Different cell types, different mechanisms
One at a time, the Bochum team introduced the nine AMPA receptor variants into the nerve cells and observed the impact on the cell architecture. In several cases, this resulted in longer dendrites with more branches. This pattern was demonstrated both for several receptor variants that allow calcium ions to flow directly into the cell through a pore and for those that activate adjacent calcium channels. “It was surprising that in the two cell classes studied, different receptor variants triggered the growth of the dendrites”, says Dr. Mohammad Hamad from the Working Group on Developmental Neurobiology. “In the inhibitory interneurons, only one of the nine variants was effective. Calcium signals are like a toolbox. However, different cell classes in the cerebral cortex make use of the toolbox in different ways.”
Hamad, M. I., Ma-Hogemeier, Z. L., Riedel, C., Conrads, C., Veitinger, T., Habijan, T., Schulz, J. N., Krause, M., Wirth, M. J., Hollmann, M., Wahle, P. (2011) Cell class-specific regulation of neocortical dendrite and spine growth by AMPA receptor splice and editing variants. Development 138, 4301-4313, doi: 10.1242/dev.07107
Further informationProf. Dr. Petra Wahle, AG Entwicklungsneurobiologie, Faculty of Biology and Biotechnology at the Ruhr-Universität, 44780 Bochum, Tel.: 0234/32-24367
Dr. Josef König | idw
Modern genetic sequencing tools give clearer picture of how corals are related
17.08.2017 | University of Washington
The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy