Outline Research Education Lectures & Courses
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Staffs

Title Name Researcher information
Professor TANAKA Kohichi
Assistant Professor HIRAOKA Yuuichi
Assistant Professor OHNISHI Tetsuo
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Outline

The final goal of our research is to understand molecular, cellular, and neuronal ensemble mechanisms underlying higher order brain functions including learning and memory. For that purpose, we combine molecular genetics, physiological and behavioral methods. The laboratory also studies the mechanism that underlies neuronal cell death and regeneration.
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Research

1. Functions of glutamate transporters in the brain
Glutamate is a major excitatory neurotransmitter and plays an important role in neuronal plasticity and neurotoxicity in the central nervous system. Glutamate transport proteins provide the mechanism by which synaptically released glutamate is inactivated and kept below toxic levels in the extracellular space. By now, five subtypes of high-affinity glutamate transporters have been identified in the mammalian brain. Our lab studies the physiological and pathological roles of glutamate transporter subtypes using subtype-specific knockout mice.
Migraines affect millions of people worldwide, often lasting days and severely disrupting lives. More than simply super-intense headaches, some migraines actually result from pathological excitation of neurons in the brain. We show that susceptibility to migraines could be related to a molecular transporter that normally works to prevent excessive excitation of neurons. Migraines are related to a condition called cortical depression, in which a large wave of hyperactivity spreads across the brain, followed by a wave of inhibition, or depressed brain activity. We hypothesized that susceptibility to cortical spreading depression (CSD) is related to disrupted transport of glutamate, the most common excitatory neurotransmitter. We found that when mice lacked the GLT-1 transporter, cortical spreading depression occurred more frequently and spread more quickly than in control mice or in the other knockout mice. If GLT-1 proves to be disrupted in people who have migraines, drug therapy that acts to increase glial reuptake of glutamate could be a reasonable therapeutic approach.

2. In vivo genome editing using AAV-CRISPR system
Genetically modified animals play critical roles in understanding neuronal development, function and disease. Conventional methods to establish transgenic animals have been a time- and labor-intensive process. To overcome these limitations, we developed a viral vector-mediated gene knock-out strategy using CRISPR/Cas9. Using this method, we found that a dopamine receptor D1R ablation in the nucleus accumbens (NAc) region effectively increased the active coping behavior in animals under stress, suggesting that the reduced dopamine release in the NAc region initiated an active coping behavior.

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Education

Goals/Outline:
Students should generate genetically modified animals to comprehensively understand the cognitive mechanisms at the level of molecule to behavior. Then, students should analyze cognitive deficits of mutant animals and those molecular mechanisms.

Available programs:
Participation in the ongoing research project; as needed
Training for cell biology: five times a year 13:00 – 16:00

Experiment:
1. Gene cloning and generation of targeting vector.
2. Generation of genetically modified mice
3. Behavioral analysis of the mice
4. Morphological analysis of central nervous systems.
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Lectures & Courses

The aim of this practice is to learn molecular biological, anatomical, electrophysiological and psychological approaches to elucidate the mechanism of cognition. Moreover, based on previous case reports of cognitive deficits, students should plan and discuss what kinds of the researches are possible and meaningful to elucidate the pathology of these diseases, leading to unveil the mechanism of cognition.
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