2-Methyl-6-(phenylethynyl)pyridine (MPEP) is a research drug which was one of the first compounds found to act as a selective
antagonist
An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.metabotropic glutamate receptor subtype mGluR5. After being originally patented as a liquid crystal for LCDs, it was developed by the pharmaceutical company
Novartis
Novartis AG is a Swiss multinational corporation, multinational pharmaceutical company, pharmaceutical corporation based in Basel, Switzerland. Novartis is one of the largest pharmaceutical companies in the world and was the eighth largest by re ...
in the late 1990s. It was found to produce neuroprotective effects following acute brain injury in animal studies, although it was unclear whether these results were purely from mGluR5 blockade as it also acts as a weak
NMDA antagonist
NMDA receptor antagonists are a class of drugs that work to antagonize, or inhibit the action of, the ''N''-Methyl-D-aspartate receptor ( NMDAR). They are commonly used as anesthetics for humans and animals; the state of anesthesia they ind ...
, and as a positive allosteric modulator of another subtype mGlu4, and there is also evidence for a functional interaction between mGluR5 and NMDA receptors in the same populations of neurons. It was also shown to produce
antidepressant
Antidepressants are a class of medications used to treat major depressive disorder, anxiety disorders, chronic pain, and addiction.
Common side effects of antidepressants include Xerostomia, dry mouth, weight gain, dizziness, headaches, akathi ...
and
anxiolytic
An anxiolytic (; also antipanic or anti-anxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxie ...
effects in animals, and to reduce the effects of morphine withdrawal, most likely due to direct interaction between mGluR5 and the μ-opioid receptor.
The main significance of MPEP has been as a lead compound to develop more potent and selective mGluR5 antagonists such as
MTEP
3-((2-Methyl-4-thiazolyl)ethynyl)pyridine (MTEP) is a research drug that was developed by Merck & Co. as a selective allosteric Antagonist (pharmacology), antagonist of the metabotropic glutamate receptor subtype Metabotropic glutamate receptor ...
, but research using MPEP itself continues, and recently it was shown to reduce self-administration of nicotine, cocaine, ketamine and heroin in animals, possibly through an MPEP-induced potentiation of the rewarding effect of the self-administered drug, and MPEP was also shown to possess weak reinforcing effects by itself.
See also
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MTEP
3-((2-Methyl-4-thiazolyl)ethynyl)pyridine (MTEP) is a research drug that was developed by Merck & Co. as a selective allosteric Antagonist (pharmacology), antagonist of the metabotropic glutamate receptor subtype Metabotropic glutamate receptor ...