mGluR5 antagonists 2-methyl-6-(phenylethynyl)-pyridine and (E)-2-methyl-6-(2-phenylethenyl)-pyridine reduce traumatic neuronal injury in vitro and in vivo by antagonizing N-methyl-D-aspartate receptors.
The effect of selective group I metabotropic glutamate receptor subtype 5 (mGluR5) antagonists 2-methyl-6-(phenylethynyl)-pyridine (MPEP) and (E)-2-methyl-6-(2-phenylethenyl)-pyridine (SIB-1893) on neuronal cell survival and post-traumatic recovery was examined using rat in vitro and in vivo trauma models. Treatment with MPEP and SIB-1893 showed significant neuroprotective effects in rat cortical neuronal cultures subjected to mechanical injury. Application of the antagonists also attenuated glutamate- and N-methyl-D-aspartate (NMDA)-induced neuronal cell death in vitro. Intracerebroventricular administration of MPEP to rats markedly improved motor recovery and reduced deficits of spatial learning after lateral fluid percussion-induced traumatic brain injury. Lesion volumes as assessed by magnetic resonance imaging were also substantially reduced by MPEP treatment. Although we show that MPEP acts as a potent mGluR5 antagonist in our culture system, where it completely blocks agonist-induced phosphoinositide hydrolysis, electrophysiological and pharmacological studies indicate that MPEP and SIB-1893 also inhibit NMDA receptor activity at higher concentrations that are neuroprotective. Taken together, these data suggest that MPEP and SIB-1893 may have therapeutic potential in brain injury, although the mechanisms of neuroprotective action for these drugs may reflect their ability to modulate NMDA receptor activity.
Movsesyan
V A
VA
Georgetown Institute for Cognitive and Computational Sciences, Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20007, USA.
O'Leary
D M
DM
Fan
L
L
Bao
W
W
Mullins
P G
PG
Knoblach
S M
SM
Faden
A I
AI
D000818:Animals; D001930:Brain Injuries / Q000188:drug therapy / Q000473:pathology* / Q000523:psychology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D018698:Glutamic Acid / Q000633:toxicity; D006868:Hydrolysis; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects; D016202:N-Methylaspartate / Q000633:toxicity; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D018691:Excitatory Amino Acid Antagonists; C578937:Grm5 protein, rat; D018696:Neuroprotective Agents; D010716:Phosphatidylinositols; D011725:Pyridines; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C120148:SIB 1893; D018698:Glutamic Acid; D016202:N-Methylaspartate; C121465:6-methyl-2-(phenylethynyl)pyridine