Guanidinoethyl sulfonate

Guanidinoethyl sulfonate (Taurocyamine) is an orally available, blood-brain permeable competitive inhibitor of taurine transporters and a competitive antagonist of glycine receptors (GlyR) (IC₅₀=565 μM). Guanidinoethyl sulfonate has both weak agonist and antagonist effects on GABA_A receptors. Guanidinoethyl sulfonate inhibits taurine transmembrane transport and competitively binds to the GlyR ligand binding domain, thereby blocking glycine-mediated chloride influx, and may regulate brain pH to exert neuroprotective effects. Guanidinoethyl sulfonate can be used for neuroprotection studies of ischemic brain injury^[1][2][3]. In Vitro:Electrophysiological experiments (Glycine receptor activity):
Guanidinoethyl sulfonate (0.5 mM; transient) competitively antagonizes glycine-induced currents in mouse striatal neurons, shifting the glycine dose-response curve to the right, with the EC₅₀ increasing from 62 μM (control group) to 154 μM (treated group)^[1].
Electrophysiological experiments (GABA receptor activity):
Guanidinoethyl sulfonate (1 mM; transient) exhibits both weak agonist and antagonist effects on GABA_A receptors in mouse striatal neurons^[1]. In Vivo:Forebrain ischemia model:
Guanidinoethyl sulfonate (625 mg/kg; intraperitoneal injection; once a day; 2 weeks) pretreatment in adult male gerbils significantly increases the survival rate of hippocampal CA1 neurons after ischemia and alleviates delayed neuronal death^[2].
Pregnancy model:
Guanidinoethyl sulfonate (1% drinking water; free drinking; gestational day 11-21) causes a significant decrease in taurine concentrations in the fetus' body, liver, brain and placenta (32%-87%), reduces fetal body weight and organ weights, and increases maternal urinary taurine excretion in the Wistar pregnant rat model^[3].