(S)-3-Hydroxyphenylglycine is an agonist of group I metabotropic glutamate receptors (mGluRs).

Hippocampal neurons in the slice preparation exhibit spontaneous synchronized bursting activity in the presence of picrotoxin, a γ-aminobutyric acid-A receptor antagonist. These synchronized bursts rarely exceed 500 ms in duration and thus resemble interictal discharges. Control shows one such synchronized burst, which typically consisted of an initial abrupt discharge 100–200 ms in duration (primary burst) followed by a series of briefer phasic discharges (secondary bursts). Addition of (S)-3-hydroxyphenylglycine (250–500 μM) significantly prolonged the synchronized burst duration, primarily via a marked increase in the number of secondary bursts. These prolonged discharges ranged from 1 to 7 s in duration (4,282 ± 1,060 ms, a 1,021?± 247% increase, n = 7), and the secondary bursts within each discharge gradually changed in amplitude and frequency[2].