Through the ramification of its fiber-like axon, a single neuron can send branches and thus transmit information into several target areas at the same time. In principle, neurobiologists distinguish between two kinds of axonal branching: branching of the growth cone at the tip of an axon and the sprouting of collaterals (interstitial branching) from the axon shaft.
Both forms of axonal branching can be observed in sensory neurons, which transmit the sensation of touch, pain and temperature, among others. When the axons of these neurons reach the spinal cord, their growth cones first split (bifurcate) and consequently the axons divide into two branches growing in opposite directions. Later new branches sprout from the shaft of these daughter axons which penetrate the gray matter of the spinal cord.
Through investigations on sensory neurons, Dr. Hannes Schmidt and his colleagues were able to identify a protein which triggers the splitting of the growth cone of the sensory axons: the peptide CNP (the abbreviation stands for C-type natriuretic peptide). In transgenic mice the scientists were able to show that CNP is formed in the spinal cord precisely when sensory neurons grow into it. In the absence of CNP bifurcation can no longer occur which results in reduced neuronal connectivity in the spinal cord.
The new findings supplement earlier discoveries of the research group of Professor Rathjen according to which a cGMP-signaling cascade is responsible for the bifurcation of sensory axons. When CNP binds to its receptor Npr2 (natriuretic peptide receptor 2) on the surface of the axons, this signaling cascade is set in motion, which in turn induces the formation of the secondary messenger molecule cGMP. This messenger molecule then activates the protein kinase cGKI (cGMP-dependent protein kinase I), which can switch on and off a whole series of target proteins. The cytoskeleton of the neurons is thus altered in such a way that their growth cone splits into two daughter axons.
Next, the researchers want to identify these target proteins. Further analyses should clarify whether the cGMP signaling cascade likewise regulates the branching of other axon systems and whether this impacts the sensation of pain.*C-type natriuretic peptide (CNP) is a bifurcation factor for sensory neurons
Correspondence to F.G. Rathjen: email@example.comBarbara Bachtler
Barbara Bachtler | idw
‘Farming’ bacteria to boost growth in the oceans
24.10.2016 | Max-Planck-Institut für marine Mikrobiologie
Calcium Induces Chronic Lung Infections
24.10.2016 | Universität Basel
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy