Lactate can aid brain cell production
Whether you're a weekend exerciser or a sports professional, lactate build-up in your muscles is a painful reminder that you're pushing a little too hard. But new research shows the compound is vital and can contribute to the generation of neurons in the brain.
The burn that comes from an intense workout, when your thighs just can’t take any more, is a signal that your body is producting lactate, which builds up in your muscles and makes it harder to keep going.
Lactate is actually a waste product that results when you're working out so hard your body can't deliver enough oxygen to your muscles, and your body is forced to burn glucose anaerobically. But it turns out that while you might not want lactate to build up in your muscles, a little lactate is actually good for your brain.
“In order to function optimally the brain needs lactate,” says Professor Linda H. Bergersen, from the University of Oslo. “Lactate can actually be a signal for the creation of new neurons and synapses in the brain.”
First to find lactate receptors
A little lactate is always circulating in our blood, but when we work our muscles we produce more. Lactate, like sugars, is known to be a source of energy for the brain and necessary for memory.
Scientists also know that the compound can provide protection against brain damage. But Bergersen and the university's Brain and Muscle Energy Group were the first to find dedicated lactate receptors in mice brains.
“This discovery represents a big change in our perception of the function of lactate in the brain. It indicates that lactate is of even greater importance to brain functionality than we thought,” she said. “Now that we’ve found the receptors and identified their effect in the cells, we can ascertain that lactate is a transmitter which triggers essential processes in neurons.”
Implications with regard to Alzheimer’s
The University of Oslo professor thinks the results offer new possibilities in the quest for delaying or preventing dementia. It may also help explain why people who are physically active tend to get Alzheimer’s later in life than others.
“Because the brain cells of people who exercise appear to function better, it can take longer for dementia to have noticeable consequences in daily life. You can die of something else before requiring care for dementia.”
“One conclusion after a host of studies is that exercise can delay dementia and have a positive effect on the brain,” says Bergersen.
But this doesn’t prove that lactate is a direct reason why people who work out tend not to be stricken by dementia as early as inactive people.
Bergersen says this research is still in stage.
Not all good?
What is clear, however, is that lactate is found in our blood and brains all the time, but at different concentrations. When we exercise we produce more lactate than when we are at rest.
Bergersen says previous studies have shown that the way lactate is produced in the body is a crucial factor.
“If it comes from physical training, it’s good for the brain. But if the lactate levels are elevated by illness, such as colon cancer, that’s not so good.”
“The variation in levels might be the reason for the difference between beneficial and deleterious effects,” she says.
Of mice and men
The new Norwegian study was conducted on the brains of mice.
The researchers linked 10 nanometre (a billionth of a metre) particles of gold to equally small protein particles and used an electron microscope to help find lactate receptors.
One area where these receptors were concentrated were in the neurons of the cerebral cortex, where they help control the activity of neurons.
Although this was a study of lab mice, Bergersen says it is readily applicable to humans.
“Human and mice brains share lots of similarities, so we can acquire basic knowledge by studying mice,” says Bergersen.
Translated by: Glenn Ostling
- Knut H. Lauritzen et.al., Lactate receptor sites link neurotransmission, neurovascular coupling, and brain energy metabolism, Cereb Cortex, May 21. 2013