MSOP is a selective group III metabotropic glutamate receptor antagonist. Displays an apparent KD of 51 μM for the L-AP4-sensitive presynaptic mGluR on primary afferent terminals in spinal cord compared to > 700 μM for the (1S,3S)-ACPD-sensitive presynaptic mGluR in the same system. MSOP has no activity on postsynaptic mGlu receptors or on ionotropic glutamate receptors on neonatal rat motoneurons.
