Wood frog brains produce ketone bodies locally during metabolic depletion

Scientists at the University of Missouri have discovered that the brains of amphibians, specifically those in the "bolovnyaki" (a colloquial term for certain amphibians), can produce their own ketone bodies when glucose levels drop. This finding challenges the long-held belief that the brain relies solely on external glucose for energy. Previously, it was understood that a decline in blood glucose could lead to neuron dysfunction and tissue damage.

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Frog in the pond

Amphibian Brains Bypass Traditional Energy Pathways

Normally, ketone bodies are synthesized by the liver and then transported by the bloodstream to the brain. However, the amphibians studied in this research exhibit a unique mechanism: their nervous systems generate energy locally, directly at the sites of glucose deficiency. Joseph Santin, the lead researcher, likens this process to a backup generator kicking in for a building that was thought to be entirely dependent on the main power grid.

A Lifeline During Hibernation

This internal energy production system is crucial for the survival of these amphibians during their hibernation period. As they enter an amphibian-like dormant state, their metabolism slows down, and energy reserves dwindle. By the spring, oxygen and fuel supplies are minimal. The brain must rapidly activate essential functions without suffering irreversible damage, a feat this newly discovered pathway facilitates.

Santin's laboratory has dedicated years to this area of study. Previous research from the team demonstrated that this dormant state protects amphibian neurons from hypoxia. This latest discovery adds another layer to that understanding, revealing how the brain maintains activity even when its primary fuel source, glucose, is compromised.

Unanswered Questions and Future Implications

While the precise trigger for this shift to a ketogenic energy pathway remains unknown, researchers have established that it functions as an emergency reserve, activated only when glucose is scarce. The exact duration of this backup energy mode is also yet to be determined, but it is understood not to be a constant state.

Given that amphibians and humans share fundamental biological processes, this research holds significant implications for human neurobiology. Understanding how brains adapt to energy scarcity could provide new insights into metabolic disorders. The study offers a potential framework for analyzing conditions such as Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and schizophrenia, all of which are associated with metabolic dysfunctions.

The findings were published in the Proceedings of the National Academy of Sciences.

Source: This commentary was adapted from an original Russian-language publication by Pravda.Ru.