醫學系一 A B 朱庭儀 B 林靖容 GABA-γ-Aminobutyric Acid, Glutamate, and Glycine

Glutamate In neuroscience, glutamate plays a key role in long-term potentiation, learning and memory. Glutamate is the precursor for the synthesis of GABA, the lack of which may lead to stiff- man syndrome.

Metabolism §R 1 -amino acid + R 2 -α-ketoacid ⇌ R 1 -α-ketoacid + R 2 -amino acid §glutamate + H 2 O + NADP + → α-ketoglutarate + NADPH + NH 3 + H + Functional uses

Neurotransmitter §Nerve impulses→release of glutamate from the pre-synaptic cell→glutamate receptors in the opposing post-synaptic cell bind with glutamate→ activated.

§Excitotoxicity due to glutamate is associated with certain diseases.

Flavor enhancer ： MSG=monosodium glutamate Nutrient Plant growth ： Auxigro NMR Spectroscopy ： alignment medium. Functional uses

Glycine Biosynthetic intermediate Neurotransmitter §Glycine is an inhibitory neurotransmitter in the central nervous system. Activation of glycine receptors are can cause an Inhibitory postsynaptic potential (IPSP).

NMDA receptor Functional role It is the predominant molecular device for controlling synaptic plasticity and memory function. Clinical significance Recently, NMDARs were associated with a rare autoimmune disease

GABA-γ-Aminobutyric acid The chief inhibitory neurotransmitter in the mammalian central nervous system Neurons that produce GABA as their output are called GABAergic neurons,like Medium Spiny Cells

GABA A –a ligand-gated ion channel

Composed of two subunits When binding to the GABA B receptor activates the trimeric G protein Inhibit voltage-gated Ca ++ channels or activate K + channels. GABA B -a G protein-coupled receptor

Structure and conformation GABA is found mostly as a zwitterion gas:highly folded solid: more extended solution: five different conformations synthesis

GABA’s applications Increase production of α waves, reduce β wave, Controls θ waves, Also involved in the production of endorphins Stimulate the production of Human Growth Hormone

Comparison Amino acidsFunction classSecretion sites GABAInhibitoryCNS; invertebrate neuromuscular junction GlutamateExcitatoryCNS; invertebrate neuromuscular junction GlycineInhibitoryCNS