MPP+

Not to be confused with MPTP or MPPP.

MPP+

Names
IUPAC name 1-Methyl-4-phenylpyridin-1-ium
Other names Cyperquat; 1-Methyl-4-phenylpyridinium; N-Methyl-4-phenylpyridine
Identifiers
CAS Number	39794-99-5 N
ChEBI	CHEBI:641 Y
ChEMBL	ChEMBL311617 Y
ChemSpider	36101 Y
EC Number	248-939-7
IUPHAR/BPS	4568
Jmol 3D model	Interactive image
MeSH	1-Methyl-4-phenylpyridinium
PubChem	39484
InChI InChI=1S/C12H12N/c1-13-9-7-12(8-10-13)11-5-3-2-4-6-11/h2-10H,1H3/q+1 Y Key: FMGYKKMPNATWHP-UHFFFAOYSA-N Y
SMILES C[n+]1=cc=c(c=c1)c2=cc=cc=c2
Properties
Chemical formula	C12H12N+
Molar mass	170.25 g/mol
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

MPP+ (1-methyl-4-phenylpyridinium) is a positively charged molecule with chemical formula C₁₂H₁₂N⁺. It is toxic and acts by interfering with oxidative phosphorylation in mitochondria by inhibiting complex I, leading to the depletion of ATP and cell death. Mitochondria in cells treated with MPP+ also display a phenotype indicative of apoptosis: small, round, and fewer in number. It also inhibits the synthesis of catecholamines, reduces levels of dopamine and cardiac norepinephrine, and inactivates tyrosine hydroxylase.

The neurotoxin MPTP is converted in the brain into MPP+ by the enzyme MAO-B, causing parkinsonism in primates by killing certain dopamine-producing neurons in the substantia nigra. MPP+-induced neurodegeneration is specific to dopamine neurons and can be prevented by drug treatment or by limiting the function of the dopamine transporter.

The chloride salt of MPP+ has been used as a herbicide under the trade name cyperquat and is structurally similar to the herbicide paraquat.

In a rat model of Parkinson's disease, nobiletin, a flavonoid found in citrus, can rescue dopaminergic neurons from degeneration caused by treatment with MPP+.