Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Exercising limbs protects brain cells affected by Parkinson’s

25.10.2004


In an animal model of Parkinson’s, exercise prevents degeneration of nerve cells that are normally impaired or destroyed by the disease, according to University of Pittsburgh researchers. Based on their work, which was presented today at the Annual Meeting of the Society for Neuroscience in San Diego, a small pilot study has been initiated in patients with Parkinson’s to determine if regular exercise has an impact on the progression of their disease.



In Parkinson’s, cells in the brain that contain dopamine, a neurotransmitter essential for purposeful and facile muscle control, progressively die until only a small percentage remains. Dopamine carries signals from the nerve cells, or neurons, located deep inside the brain in an area called the substantia nigra along nerve fibers that end in the brain’s striatum, an area involved in control of movement. In the absence of dopamine, neurons can’t send the appropriate messages for smooth motor control, resulting in the telltale symptoms of Parkinson’s: uncontrollable tremors, rigidity of limbs, slow movements and stooped posture.

In one of the studies presented by Annie D. Cohen, a doctoral student in the department of neurology and Center for Neuroscience at the University of Pittsburgh School of Medicine, the researchers examined the brains of rats that had been forced to exercise for seven days before receiving a toxin that normally induces Parkinson’s disease. They found that, compared to animals that had not been exercised, significantly fewer dopamine-containing neurons died.


"Whereas a number of explanations could be offered as to why the exercised animals do so well, we have evidence that indicates it’s because exercise stimulates production of key proteins that are important for survival of neurons," said the study’s senior author, Michael J. Zigmond, Ph.D., professor of neurology, neurobiology and psychiatry, and co-director of the Parkinson’s Disease Center of Excellence at the University of Pittsburgh School of Medicine.

Called neurotrophic factors, these proteins protect neurons and promote their survival. According to the researchers’ studies, one particular neurotrophic factor, glial cell line-derived neurotropic factor, or GDNF, is increased with exercise by 40 percent. "GDNF, and probably other factors as well, may help offset the cell’s vulnerability to the effects of oxidative stress from free radical molecules that are produced by the toxin we use in our rat model," Dr. Zigmond explained.

Parkinson’s is induced by giving animals a substance called 6-hydroxydopamine (6-OHDA). The toxin results in brain pathology that mimics what is seen in human disease - a decrease of dopamine-containing neurons in the substantia nigra and of axon terminals in the striatum, the site where dopamine is usually released.

When delivered to one side of the brain, 6-OHDA causes movement deficits in the limbs on the opposite side. If a cast is placed on the animal’s left forelimb, for example, and 6-OHDA is administered to the left side of the brain, the toxin would normally cause the right forelimb to be impaired. But this is not the case. Earlier studies by Timothy Schallert, Ph.D., at the University of Texas in Austin, found that by immobilizing the left arm – the good arm – the rat has no choice but to use its right arm and does so without much difficulty.

To determine if forcing exercise of a particular limb could be protective against Parkinson’s, Dr. Zigmond’s group performed a study whereby one forelimb was immobilized in a cast for seven days, placing more physical demands on the free forelimb. After the cast was removed, 6-OHDA was administered to the brain on the same side as the limb that had been casted. The researchers observed no deficits in movement with either limb. Most importantly, the limb that had been exercised and should have been affected by the toxin was fine.

In addition, reported Ms. Cohen, an analysis of brain tissue 28 days after 6-OHDA injection found that in the animals that were forced to exercise their limb, only 6 percent of dopamine-containing neurons were lost. But in animals given the toxin without prior exercise, these neurons were reduced by 87 percent. "We looked for certain cell markers to assess to what extent exercise was protective against degeneration, and even at two days after 6-OHDA administration we saw there to be a protective effect. Our data suggest the possibility that exercise can make dopamine neurons resistant to neurotoxins and may therefore be a useful therapy for Parkinson’s disease," noted Ms. Cohen.

"Whether exercise can reduce the risk of Parkinson’s disease or can slow down its progression are intriguing questions. We are certainly encouraged that in our experimental models we can demonstrate that this sort of forced exercise improves motor function and protects the neurons affected by the disease," added Dr. Zigmond. "In a collaboration with Dr. Shallert’s lab at the University of Texas, we are now looking at more clinically relevant forms of exercise, such as running. We also plan to look at the effects of housing our rats in an enriched environment."

As an extension to their animal research, Dr. Zigmond has enlisted Anthony DeLitto, Ph.D., P.T., FAPTA, and colleagues from the University of Pittsburgh School of Health and Rehabilitation Sciences to begin a study whereby patients with Parkinson’s disease are enrolled in a 60-minute exercise program that meets three times a week. The study plans to enroll 20 patients in its initial phase.

In addition to Zigmond, other authors of the abstract presented by Ms. Cohen are Amina El Ayadi, Ph.D., and Amanda Smith, Ph.D., also from the department of neurology at the University of Pittsburgh School of Medicine. Related studies also were presented by Niklas Lindgren, Ph.D., and Eva Lin, Ph.D., both from the department of neurology; and Jane E. Cavanaugh, Ph.D., of the department of pharmacology. Their research was supported by grants from the National Institute of Neurological Disorders and Stroke, the United States Army, and the Michael J. Fox Foundation.

Lisa Rossi | EurekAlert!
Further information:
http://www.upmc.edu

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

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...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

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...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>