Anxiolytics:Glutamate: Blockade of the mGlu5 receptor decreases basal and stress-induced cortical norepinephrine in rodents.

Entrez PubMed: "Glutamate, the major excitatory neurotransmitter in the brain mediates its effects by both ionotropic and metabotropic receptor subtypes. Recently, the search for selective ligands for glutamate receptor subtypes has led to the discovery of 2-methyl-6-(phenylethynyl)pyridine (MPEP), an antagonist specific for metabotropic glutamate receptor 5 (mGlu5). This receptor is highly expressed in limbic forebrain regions and is thought to modulate anxiety-related processes. The noradrenergic nucleus locus coeruleus (LC) is an important mediator of stress responses and dysfunction of this system is implicated in affective disorders such as anxiety and depression. . . Blockade of the mGlu5 receptor elicited significant reductions in extracellular NE in the frontal cortex. The benzodiazepine diazepam also reduced cortical NE. Furthermore, MPEP administration attenuated stress-induced increases in extracellular NE. Taken together, these data show that MPEP and MTEP, through their blockade of the mGlu5, reduce extracellular norepinephrine, the impact of which may contribute to their anxiolytic actions."

Blockade of the mGlu5 receptor decreases basal and stress-induced cortical norepinephrine in rodents.
Page ME, Szeliga P, Gasparini F, Cryan JF.
Psychopharmacology (Berl). 2005 Apr;179(1):240-6. Epub 2005 Feb 17.