GlycinevsTaurine

Glycine acts as an inhibitory neurotransmitter by binding to strychnine-sensitive glycine receptors (GlyR) in the brainstem, spinal cord, and retina, hyperpolarizing neurons via chloride influx. It also serves as a mandatory co-agonist at the glycine-binding site (NR1 subunit) of NMDA glutamate receptors — without glycine binding, NMDA receptors cannot open their ion channel even when glutamate is present. This dual role means glycine both calms neural activity (sleep, anti-anxiety via GlyR) and supports excitatory learning processes (NMDA-dependent LTP and memory consolidation). Glycine lowers core body temperature at night by promoting peripheral vasodilation through nitric oxide, which improves sleep onset. It is a precursor for glutathione synthesis and modulates the glycinergic system in the suprachiasmatic nucleus.

Taurine activates GABA-A receptors (particularly extrasynaptic δ-containing subtypes) and glycine receptors (GlyR) as a partial agonist, providing inhibitory modulation that reduces neural excitability and hyperexcitability. It acts as a powerful antioxidant, scavenging hypochlorous acid, hydroxyl radicals, and peroxynitrite in mitochondria and cytosol. Taurine regulates calcium homeostasis via modulation of ryanodine receptors and IP3 receptors, preventing excitotoxic calcium overload. It modulates osmotic balance through the taurine transporter (TauT/SLC6A6) to protect cells from swelling under stress. Taurine may enhance mitochondrial function and biogenesis. Recent research shows it maintains telomere length, reduces cellular senescence markers (p16, p21), and modulates the mTOR pathway.