The researchers, Marco Prado, Marc Caron, Vania Prado, and their colleagues, said their findings reveal a critical role in central nervous system (CNS) function for the component of the reloading machinery, called an acetylcholine transporter, that they knocked out.
They also said their findings suggest that the mouse model will be useful in understanding how defects in neurons that use acetylcholine to trigger one another contribute to cognitive decline in such disorders as Alzheimer's disease (AD) and aging. The researchers published their finding in the September 7, 2006, issue of the journal Neuron, published by Cell Press.
To explore the role of the acetylcholine transporter, the researchers genetically modified mice to either completely lack the transporter gene or to have reduced levels of it. Such transporters normally retrieve acetylcholine that one neuron has used to trigger another and transport it to storage sacs called vesicles that are the reservoir for neurotransmitter for subsequent use. The researchers found that such transporter-deficient mice were less able to fill such vesicles with acetylcholine.
In behavioral tests, the researchers found that the mice with lower levels of the transporter were less able to learn to hang on to a rotating rod than normal mice. Mice completely lacking the transporter were totally unable to manage the task because they lacked physical endurance. Thus, wrote the researchers, those mice might be useful models for studying the effects of reduced acetylcholine release in certain neuromuscular disorders.
Both normal mice and those with reduced transporter were equally able to learn and remember to avoid a mild shock. However, the reduced-transporter mice showed deficits in object recognition--significantly less able to remember that they had encountered specific-shaped plastic blocks before. The altered mice also showed less memory of "intruder" mice placed in their cages--evidence of reduced social recognition.
Significantly, the researchers found that when they used a drug to enhance acetylcholine in the transporter-deficient mice, those mice showed improved performance on social recognition tests, implying that the deficit in social recognition was caused by a reduction in "cholinergic tone."
Prado, Caron, and their colleagues concluded that "Our observations support the notion that reduced cholinergic tone in AD mouse models can indeed cause deficits in social memory. However, based on somewhat similar impairments found in the object and social recognition tasks, it is possible that mild cholinergic deficits may cause a more general memory deficit for recognizing previously learned complex cues, whether social or not. Future detailed investigations will be necessary to further define the specific type of cognitive processing affected by cholinergic deficits in these mutants.
"Such studies in mouse models of reduced cholinergic tone may be particularly informative for understanding the contribution of cholinergic decline to specific behavioral alterations observed in certain pathologies of the CNS and may even be helpful in understanding physiological aging," wrote the researchers.
AI-driven single blood cell classification: New method to support physicians in leukemia diagnostics
13.11.2019 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Small RNAs link immune system and brain cells
13.11.2019 | Goethe-Universität Frankfurt am Main
If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.
Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...
Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...
In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.
An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...
An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.
The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.
Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...
05.11.2019 | Event News
30.10.2019 | Event News
02.10.2019 | Event News
12.11.2019 | Machine Engineering
12.11.2019 | Power and Electrical Engineering
12.11.2019 | Physics and Astronomy