Background:

IC50: 5 nM

MTEP is a selective metabotropic glutamate receptor subtype 5 (mGluR5) antagonist.

The mGluRs are classified into three groups: group I (mGluR1 and 5), group II (mGluR2 and 3) and group III (mGluR4, 6, 7 and 8). mGluR5 belonging to group I is excitatory, mainly localized at the edge of axo-spinous and axodendritic synaptic junctions.

In vitro: Like MPEP, MTEP showed a nanomolar affinity for mGluR5, but seemed to be superior to MPEP in term of specificity. MTEP did not influence mGluR2, mGluR7, NMDA, AMPA or kainate receptors, while inhibited MAOA at a concentration three times higher than MPEP. Moreover, recent study indicated that MTEP was five times stronger that MPEP as an anxiolytic compound [1].

In vivo: MTEP with doses between 0.5 and 3 mg/kg was found to decrease the haloperidol-induced muscle rigidity, which was measured as an increased muscle resistance of the rat hind leg. The longest and strongest effect was observed with the dose of 1 mg/kg. MTEP was also found to reduce the haloperidol-induced increase in electromyographic activity recorded in the tibialis anterior and gastrocnemius muscles. 3 and 5 mg/kg of MTEP could inhibit the haloperidol- induced catalepsy [1].

Clinical trial: N/A

Reference:
[1] Ossowska K,Konieczny J,Wolfarth S,Pilc A.  MTEP, a new selective antagonist of the metabotropic glutamate receptor subtype 5 (mGluR5), produces antiparkinsonian-like effects in rats. Neuropharmacology.2005 Sep;49(4):447-55.