Pigmented neurons

It is widely accepted that Parkinson s disease primarily results from degeneration of pigmented neurons in the substantia nigra (Gibb 1998). This causes a loss of nigrostriatal projections and lack of dopamine modulation in the striatum. In addition to loss of neurons, many of the remaining neurons contain Lewy bodies. 

MPTP N-demethyiation is cataiyzed by CYP2D6. in situ hybridization shows CYP2D6 localized in pigmented neurons of human substantia nigra (Gilham et al., 1997). 

J. Nathans. 1999. The evolution and physiology of human color vision Insights from molecular genetic studies of visual pigments Neuron 24 299-312. (PubMed)... 

Investigation of phospholipid catabolic and anabolic enzymes revealed lower activity of PLA2 and phosphoethanolamine- and phosphocholine-cytidylyltransferases in autopsied substantia nigra of patients with idiopathic Parkinson s disease. The decreased rate of phospholipid turnover in the pigmented neurons of the substantia nigra might result in reduced ability to repair oxidative membrane damage and thus accumulation of OxPL in Parkinson s disease (Ross et al. 2001). 

Moller, A. (1992) Mean volume of pigmented neurons in the substantia nigra in Parkinson s disease. Acta Neurol. Scarul. 85 (Suppl. 137) 37-39. 

Neuromelanin is a by-product of the synthesis of monoamine neurotransmitters. The loss of pigmented neurons is seen in a variety of neurodegenerative diseases. In PD, there is massive loss of dopamine producing pigmented neurons in the substantia nigra. In AD, there is an almost complete loss of the norepinephrine-producing pigmented neurons of the locus ceruleus. 

McGinness J (1985) A New View of Pigmented Neurons. J Theor Biol 115 475... 

Neuromelanin, a dark colored pigment and product of the oxidative metabolism of dopamine, is found in the cytoplasm of dopaminergic neurons of the human substantia nigra pars compacta. Neuromelanin deposits increase with age, matching the age distribution of Parkinson s disease. In the absence of significant quantities of iron, neuromelanin can act as an antioxidant in... 

Cyanidin is the most common anthocyanin in foods. In addition, anthocyanins are stabilized by the formation of complexes with other flavonoids (co-pigmentation). In the United States, the daily anthocyanin consumption is estimated at about 200 mg. Several promising studies have reported that consumption of anthocyanin-rich foods is associated with reductions of the risks of cancers - and atherosclerosis and with preventive effects against age-related neuronal and behavioral declines. These beneficial effects of anthocyanins might be related to their reported biological actions such as modulators of immune response and as antioxidants. Knowledge of anthocyanin bioavailability and metabolism is thus essential to better understand their positive health effects. 

Drosophila Ddc is expressed primarily in the CNS and the hypoderm, the epithelial layer of the fly that secretes the cuticle. In the CNS, Ddc is expressed in a small subset of neurons that produce either dopamine or serotonin (Budnik and White, 1988 Valles and White, 1988). In the hypoderm, Ddc expression leads to synthesis of dopamine, which is further metabolized into quinones that have a vital function in the cross-linking, hardening, and pigmentation of the fly cuticle (Wright, 1987). The developmental profile of DDC activity in these two tissues is quite different (Hirsh, 1986). DDC is first detected during late embryo-... 

Large amounts of iron are sequestered in substantia nigra and in locus coerulus as a neuromelanin-iron complex in dopaminergic neurons particularly in PD. Neuromelanin, a granular dark brown pigment, is produced in catecholaminergic neurons of the SN and... 

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