Description
(R,S)-CHPG is a potent and selective agonist at metabotropic glutamate receptor 5 (mGluR5). In CHO cells, it had an EC50 of 750 μM for calcium mobilization in mGluR5a-expressing cells but was inactive in mGluR1a-expressing cells. In transfected HEK293 cells, (R,S)-CHPG bound mGluR1a and mGluR5a (Kis = 0.9 and 3.9 μM, respectively) but not ionotropic glutamate receptors. It reduced oxidative stress and inflammatory markers in cultured BV-2 microglial cells. In mouse models of traumatic brain injury, it reduced lesion volume, improved sensorimotor deficits in the beam walk test, and improved spatial memory in the Morris water maze.
Uses
CHPG is a selective mGluR-5 agonist.
Biological Activity
A selective mGlu 5 metabotropic glutamate receptor agonist, completely inactive at mGlu 1a receptors expressed in CHO cells. Active in vivo .
in vitro
(r,s)-2-chloro-5-hydroxyphenylglycine [chpg] selectively activated mglu5a receptors with no activation of mglu1a receptors. this selective mglu5 receptor agonist also enhances nmda-induced depolarizations in rat hippocampalslices. chpg may be used to study the role of mglu5 receptors in the cns [1].
in vivo
to compare the effects of treatment with the newly developed selective mglur5 antagonist mpep and the selective mglur5 agonist chpg in a rat intraluminal filament model of temporary middle cerebral artery occlusion (mcao), rats, after induction of ischemia for 2 h, were administered mpep or chpg (i.c.v.) beginning 15 or 135 min. measured after either 22 or 70 h of reperfusion measured infarct size, and quantified neurological function at 2, 24, 48 and 72 h. 24 h infarct volumes after treatment with mpep or chpg at 15 min were reduced by 61 and 44%, respectively. the neuroprotective effects were dose-dependent. the neuroprotective effects were eliminated by delaying mpep treatment until 135 min. in other studies, with early mpep treatment (15 min) at optimal doses, infarct volume was reduced by 44% at 72 h, being correlated with significant neurological recovery [2].
References
[1] doherty aj, palmer mj, henley jm, collingridge gl, jane de. (rs)-2-chloro-5-hydroxyphenylglycine (chpg) activates mglu5, but no mglu1, receptors expressed in cho cells and potentiates nmda responses in the hippocampus. neuropharmacology. 1997 feb;36(2):265-7.
[2]. bao wl, williams aj, faden ai, tortella fc. selective mglur5 receptor antagonist or agonist provides neuroprotection in a rat model of focal cerebral ischemia. brain res. 2001 dec 20;922(2):173-9.
