By use of histochemical methods, a survey has been made of the localization of catecholamine to neuronal perikarya and processes in relation to neuromelanin accumulation in neuronal perikarya in the hypothalamus of dogs of various ages. Catecholamine was visualized in sections as a green fluorescence by means of the formaldehyde gasinduced fluorescence method of Falck and Hillarp. Neuromelanin,...

OBJECTIVE Diseases presenting extrapyramidal symptoms are accompanied by nigral cell loss. In the previous study, we demonstrated the reduction of the neuromelanin-positive volume of substantia nigra (SN) pars compacta (SNc) in patients with Parkinson's disease (PD) using 3-Tesla MRI. In the present study we investigated the neuromelanin-positive SNc volume in patients with the other parkinsoni...

PURPOSE To investigate age-related changes in the locus ceruleus (LC) in healthy subjects using neuromelanin magnetic resonance (MR) imaging at 3 Tesla. METHODS We examined 64 healthy volunteers (aged 23 to 80 years) using neuromelanin-sensitive T1-weighted images and measured the contrast of areas of high signal intensity corresponding to the LC. RESULTS A pair of punctate areas of high si...

The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome ha...

The massive, early and relatively circumscribed death of the dopaminergic neurons of the substantia nigra in Parkinson's disease has not yet been adequately explained. The characteristic feature of this brain region is the presence of neuromelanin pigment within the vulnerable neurons. We suggest that neuromelanin in the Parkinson's disease brain differs to that in the normal brain. The interac...

PURPOSE Neuromelanin is a dark pigment granule present within certain catecholamine neurons of the human brain. Here, we aimed to clarify the relationship between contrast of neuromelanin-sensitive magnetic resonance imaging (MRI) and MR relaxation times using T1, T2, and T2* mapping of the lower midbrain. METHODS The subjects were 14 healthy volunteers (11 men and 3 women, mean age 29.9 ± 6....

Neuromelanin (NM) is a complex polymer pigment found primarily in the dopaminergic neurons of the human substantia nigra. The structure of NM is only partially characterized, and its synthesis pathway remains unknown. We used nuclear magnetic and infrared spectroscopy to examine the structure of human NM isolated from the substantia nigra compared with synthetic dopamine melanins. Biochemical a...

The development and application of neuromelanin sensitive MR imaging has allowed the detection of significant changes in the substantia nigra (SN) of Parkinson’s disease (PD) patients, with high sensitivity and specificity in differentiating PD patients from non-PD aged controls, even in early disease stages, namely at the time of clinical diagnosis. These MR neuromelanin changes in the SN of P...

PURPOSE Parkinson disease and related syndromes are associated directly with the concentrations of neuromelanin, iron and other heavy metals, and nowadays it is discussed the possible protective role of neuromelanin by the sequester redox active iron ions, reducing the formation of free hydroxyl radicals and therefore inactivating the iron ions that induce oxidative stress. The aim of this work...

Agents suppressing microglial activation are attracting attention as candidate drugs for neuroprotection in Parkinson s disease (PD): While different mechanisms including environmental toxins and genetic factors initiate neuronal damage in the substantia nigra and striatum in PD, there is unequivocal evidence that activation of neuroinflammatory cells aggravates this neurodegenerative process. ...