Study sheds light on nerve regeneration following spinal cord injury

November 21, 2013
McClellan discovered how the sea lamprey, an eel-like fish, regrows the neurons that comprise the long nerve "highways" that link the brain to the spinal cord. Credit: MU News Bureau

Fish, unlike humans, can regenerate nerve connections and recover normal mobility following an injury to their spinal cord. Now, University of Missouri researchers have discovered how the sea lamprey, an eel-like fish, regrows the neurons that comprise the long nerve "highways" that link the brain to the spinal cord. Findings may guide future efforts to promote recovery in humans who have suffered spinal cord injuries.

"There is a lot of attention to why, following a injury, neurons regenerate in lower vertebrates, such as the , and why they don't in higher vertebrates, such as humans," said Andrew McClellan, professor of biological sciences in the College of Arts and Science and director of the MU Spinal Cord Injury Program.

The study focuses on the regrowth of a particular group of called reticulospinal neurons, which are necessary for locomotion. These neurons are found in the hindbrain, or the brainstem, and send signals to the spinal cord of all vertebrates to control movements of the body, such as locomotor behavior. When these nerve cells are damaged by a spinal cord injury, the animal is unable to move below the level of injury. While humans and other higher vertebrates would be permanently paralyzed, the sea lamprey and other lower vertebrates have the ability to regrow these neurons and recover the ability to move within a few short weeks.

In the study, McClellan and his colleagues isolated and removed injured reticulospinal neurons from sea lamprey and grew them in cultures. They applied chemicals that activated a group of molecules, called second messengers, to see what effects they had on these neurons' growth. They discovered that activation of cyclic AMP, a molecule that relays chemical signals inside cells, acted somewhat like an "on" switch—essentially converting neurons from a non-growing state to a growing one. However, it had no effect on that had already begun to grow.

McClellan says that the information learned from the study may shed light on studies of in mammals, including humans.

"In mammals, cyclic AMP does appear to enhance neural regeneration within the central nervous system in an environment that normally inhibits regeneration," McClellan said. "Cyclic AMP seems to be able to overcome some of these inhibitory factors and promotes at least some regeneration. Hopefully our studies with the lamprey can provide a list of conditions that are important for neural regeneration to help guide therapies in higher vertebrates, and possibly in humans."

Explore further: Scientists find genes linked to human neurological disorders in sea lamprey genome

More information: "Cyclic AMP stimulates neurite outgrowth of lamprey reticulospinal neurons without substantially altering their biophysical properties," Neuroscience, 2013.

Related Stories

Scientists find genes linked to human neurological disorders in sea lamprey genome

February 24, 2013
Scientists at the Marine Biological Laboratory (MBL) have identified several genes linked to human neurological disorders, including Alzheimer's disease, Parkinson's disease and spinal cord injury, in the sea lamprey, a vertebrate ...

Stem cell scarring aids recovery from spinal cord injury

October 31, 2013
In a new study, researchers at Karolinska Institutet in Sweden show that the scar tissue formed by stem cells after a spinal cord injury does not impair recovery; in fact, stem cell scarring confines the damage. The findings, ...

Technique to promote nerve regeneration after spinal cord injury restores bladder function in rats

June 25, 2013
Using a novel technique to promote the regeneration of nerve cells across the site of severe spinal cord injury, researchers have restored bladder function in paralyzed adult rats, according to a study in the June 26 issue ...

Researcher focuses on the repair of spinal cords

November 11, 2013
A spinal cord injury can be a devastating condition, often resulting in life-long disability and a range of secondary complications.

Scientists identify clue to regrowing nerve cells

November 7, 2013
Researchers at Washington University School of Medicine in St. Louis have identified a chain reaction that triggers the regrowth of some damaged nerve cell branches, a discovery that one day may help improve treatments for ...

Zebrafish reveal promising mechanism for healing spinal cord injury

July 6, 2012
Scientists in Australia are studying the mechanisms of spinal cord repair in zebrafish, which unlike humans and other mammals can regenerate their spinal cord following injury. Their findings suggest a family of molecules ...

Recommended for you

In witnessing the brain's 'aha!' moment, scientists shed light on biology of consciousness

July 27, 2017
Columbia scientists have identified the brain's 'aha!' moment—that flash in time when you suddenly become aware of information, such as knowing the answer to a difficult question. Today's findings in humans, combined with ...

Scientists block evolution's molecular nerve pruning in rodents

July 27, 2017
Researchers investigating why some people suffer from motor disabilities report they may have dialed back evolution's clock a few ticks by blocking molecular pruning of sophisticated brain-to-limb nerve connections in maturing ...

Social influences can override aggression in male mice, study shows

July 27, 2017
Stanford University School of Medicine investigators have identified a cluster of nerve cells in the male mouse's brain that, when activated, triggers territorial rage in a variety of situations. Activating the same cluster ...

Scientists become research subjects in after-hours brain-scanning project

July 27, 2017
A quest to analyze the unique features of individual human brains evolved into the so-called Midnight Scan Club, a group of scientists who had big ideas but almost no funding and little time to research the trillions of neural ...

Researchers reveal unusual chemistry of protein with role in neurodegenerative disorders

July 27, 2017
A common feature of neurodegenerative diseases is the formation of permanent tangles of insoluble proteins in cells. The beta-amyloid plaques found in people with Alzheimer's disease and the inclusion bodies in motor neurons ...

Mother's brain reward response to offspring reduced by substance addiction

July 27, 2017
Maternal addiction and its effects on children is a major public health problem, often leading to high rates of child abuse, neglect and foster care placement. In a study published today in the journal Human Brain Mapping, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.