The Effect of Peripheral Administration of Monosodium Glutamate on Ionotropic Glutamate Receptor Signalling in the Mouse Brain in Vivo Shown Through Manganese Enhanced MRI

Mohammed Khair Hankir^1,2, James R. Parkinson¹, Stephen R. Bloom³, Jimmy David Bell¹

Peripheral administration of monosodium glutamate (MSG) stimulates feeding in rodents. This may be due to the direct activation of glutamate receptors expressed in the arcuate nucleus (ARC) of the hypothalamus. We have used manganese enhanced MRI (MEMRI) to demonstrate that intraperitoneal administration of MSG dose dependently increases Mn2+ influx into the ARC and that this can be suppressed with a glutamate receptor subtype specific receptor antagonist. These results reveal that MEMRI is a sufficiently sensitive tool to detect glutamatergic signalling in vivo with high temporal and spatial resolution.