In a new study published in The Journal of Neuroscience and presented at the American Physiology Summit earlier this month, graduate student Nikolaus Bueschke, postdoctoral fellow Dr. Lara Amaral-Silva and Dr. Joseph Santin (University of Missouri, Columbia) together with researchers Min Hu and Alvaro Alvarez (University of North Carolina at Greensboro), explored how bullfrogs (Lithobates catesbeianus) emerging from hibernation tolerate hypoxia while they kickstart physiological functions in ice-covered ponds. This tolerance is in stark contrast to many other vertebrates, and non-hibernating bullfrogs, that can only tolerate hypoxia for several minutes.

When the brain experiences severe energy stress, such as low environmental oxygen (i.e. hypoxia), it responds initially with overly excited neuronal responses, which are quickly followed by cell death. This loss of brain compensation and homeostasis during energy stress is thought to be related to malfunctioning NMDA receptors, which move calcium across cell membranes.

Hibernating bullfrogs, on the other hand, exhibit remarkable resilience to hypoxia-induced stress, as their brainstem permits them to regain motor function necessary for breathing as they awake from hibernation in ice-covered ponds, without resulting in overactive neurons and cell death. This new study provides evidence showing that hibernation makes the neurons less excitable and suppresses calcium signaling by the NMDA receptor.

Information learned from these studies may help inform clinical research and uncover novel ways to protect the brain in hypoxic environments as well as during hypoxic events, such as strokes.

Source:

N Bueschke, L Amaral-Silva, M Hu, A Alvarez, JM Santin. Plasticity in the functional properties of NMDA receptors improves network stability during severe energy stress. The Journal of Neuroscience. 44(9): e0502232024, 2024.

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Categories: Comparative Physiology, Environment, Extreme Animals, Hibernation and Hypoxia, Intelligence and Neuroscience, Nature's Solutions, Physiology on the Road

Tags: American Physiological Society, American Physiology Summit, brain, Bullfrog, health, hypoxia, mental-health, neuroscience, science, stroke