DNQX (6,7-dinitroquinoxaline-2,3-dione) is a competitive antagonist at

AMPA α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, better known as AMPA, is a compound that is a specific agonist for the AMPA receptor, where it mimics the effects of the neurotransmitter glutamate Glutamic acid (symbol Glu or E; kn ...

and kainate receptors, two ionotropic glutamate receptor (iGluR) subfamilies. It is used in a variety of

molecular biology Molecular biology is a branch of biology that seeks to understand the molecule, molecular basis of biological activity in and between Cell (biology), cells, including biomolecule, biomolecular synthesis, modification, mechanisms, and interactio ...

subfields, notably

neurophysiology Neurophysiology is a branch of physiology and neuroscience concerned with the functions of the nervous system and their mechanisms. The term ''neurophysiology'' originates from the Greek word ''νεῦρον'' ("nerve") and ''physiology'' (whic ...

, to assist researchers in determining the properties of various types of

ion channels Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ...

and their potential applications in medicine. DNQX (an

receptor antagonist A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of rec ...

) displays significant effects on neurons. When applied to rat

hippocampus The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the ...

neurons in culture, it produces a dose-dependent

neurotoxicity Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

which intriguingly seems to operate through a mechanism independent of ionotropic glutamate receptors. This effect is specific to neurons and does not impact the surrounding

glial cells Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up ...

. In the context of

amphetamine Amphetamine (contracted from Alpha and beta carbon, alpha-methylphenethylamine, methylphenethylamine) is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, an ...

-induced behavioral sensitization in mice, DNQX demonstrates the capacity to block both the onset and the manifestation of this sensitization. Rather than impacting the overall

activity, DNQX specifically intervenes in the sensitization process. This phenomenon might be attributed to the activation of excitatory amino acid receptors which subsequently provoke an increased

dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized ...

release in the

striatum The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamat ...

. Therefore, DNQX's actions appear to be both potent and specific hinting at complex mechanisms beyond traditional ionotropic glutamate receptor pathways. An activation of both AMPA/kainate and dopaminergic receptors in the

nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for ' nucleus adjacent to the septum') is a region in the basal forebrain rostral to the preoptic area of the hypo ...

may be crucial for the reward response triggered by

psychostimulant Stimulants (also known as central nervous system stimulants, or psychostimulants, or colloquially as uppers) are a class of drugs that increase alertness. They are used for various purposes, such as enhancing attention, motivation, cognition ...

drugs.

Dopaminergic Dopaminergic means "related to dopamine" (literally, "working on dopamine"), a common neurotransmitter. Dopaminergic substances or actions increase dopamine-related activity in the brain. Dopaminergic pathways, Dopaminergic brain pathways facil ...

antagonists 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.cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...

, a common measure of drug reward. In experiments where DNQX, an

AMPA receptor The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptor, AMPAR, or quisqualate receptor) is an ionotropic receptor, ionotropic glutamate receptor (iGluR) and predominantly sodium ion channel that mediates fast excitator ...

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.AMPA receptors The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptor, AMPAR, or quisqualate receptor) is an ionotropic receptor, ionotropic glutamate receptor (iGluR) and predominantly sodium ion channel that mediates fast excitator ...

' role in this process. Conversely, the

dopaminergic Dopaminergic means "related to dopamine" (literally, "working on dopamine"), a common neurotransmitter. Dopaminergic substances or actions increase dopamine-related activity in the brain. Dopaminergic pathways, Dopaminergic brain pathways facil ...

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.fluphenazine did not alter cocaine-induced place preference, possibly due to adaptations following repeated drug exposure. Both DNQX and fluphenazine blocked the expression of conditioned place preference in rats previously trained with cocaine alone, indicating the involvement of both AMPA and

receptors in the expression of cocaine-induced place preference.

References

External links

DNQX MSDS
{{Ionotropic glutamate receptor modulators AMPA receptor antagonists Kainate receptor antagonists NMDA receptor antagonists Nitroarenes Quinoxalines Quinones Lactams

See also

References

External links