How lack of oxygen affects the formation of memory in brain

Research has revealed the brain’s response to temporary oxygen deprivation is anoxia-induced long-term potentiation (aLTP).
In a new study published in iScience, researchers from the Okinawa Institute of Science and Technology (OIST) and their collaborators have discovered an important mechanism that may explain the memory loss seen in conditions such as stroke.
The study revealed the brain’s effects on temporary oxygen deprivation, known as anoxia-induced long-term potentiation (aLTP).
When the brain experiences a lack of oxygen, neurons release excessive amounts of the neurotransmitter glutamate. This increased glutamate stimulates the production of nitric oxide (NO) in neurons and cerebral blood vessels.
According to the researchers, this NO then increases the release of glutamate from neurons, forming a self-sustaining glutamate-NO-glutamate feedback loop.
“We want to know how oxygen depletion affects our brain and how this change occurs,” said Dr. Han-Ying Wang, lead author of the study. Nitric oxide is known to be involved in the release of glutamate in the brain during oxygen deprivation, but the mechanism is unclear. “
Hijack the secret process
The cellular processes that support ALTP are shared with those involved in memory consolidation and learning, known as long-term potentiation (LTP). If ALTP is present, it hijacks the molecular mechanism required for LTP, which can interfere with memory formation.
“Long-term maintenance of ALTP requires continuous nitric oxide synthesis. NO synthesis is self-sustaining, supported by the NO-glutamate cycle, but blocking the molecular steps for NO-synthesis or causing the release of glutamate ultimately disrupts the cycle and aLTP explained Professor Tomoyuki. Takahashi, former head of the Department Cellular and Molecular Synaptic Functions at OIST.
When the brain is deprived of oxygen during a stroke, amnesia – the loss of recent memories – can be one of the symptoms.
ALTP disruption may disrupt the brain’s process of consolidating memory and may explain the memory loss seen in some patients after stroke, researchers suggest.
“If we can figure out what happens when those neurons are deprived of oxygen, it can inform how to treat stroke patients,” said Dr. Patrick Stone, a scientist in the OIST Department of Sensory and Behavioral Neuroscience.
Prof. Takahashi says the important finding is that a positive feedback loop is formed between glutamate and NO when the brain is temporarily deprived of oxygen. It explains the long-lasting nature of ALTP and may offer a solution to memory loss caused by oxygen deprivation.
This research not only reveals the effects of oxygen deprivation on the brain, but also opens new avenues for potential therapeutic interventions to address memory loss associated with conditions such as stroke.