Effect of electrical stimulation on the fluorescence intensity of catecholamine‐containing tuberal nerve cells*

Lichtensteiger, W.

doi:10.1113/jphysiol.1971.sp009604

Cited by 21 publications

(8 citation statements)

References 19 publications

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“…The following points justify the fact that this parameter reflects the formation of melanin. The concentration of dopamine used in our assay (1 raM) was based on estimations of dopamine concentration in the cytoplasm of dopaminergic cells (Lichtensteiger, 1971;Lichtensteiger et al, 1976Lichtensteiger et al, , 1979. Second, using an assay similar to ours, Rodgers and Curzon (1975) showed earlier that incorporation of dopamine into TCA-precipitable polymers parallels the increase in absorbance and is dependent on the presence of oxygen.…”

Section: Measurement Of Melanin Synthesismentioning

confidence: 94%

Neuromelanin synthesis in rat and human substantia nigra

Rabey

Hefti

1990

J Neural Transm Gen Sect

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A relation between neuromelanin synthesis and vulnerability of dopaminergic neurons is suggested by the fact that heavily pigmented cells are preferentially lost in aging and Parkinson's disease and that the dopaminergic neurotoxin MPP+ (1-methyl-4-phenyl-pyridine) binds to neuromelanin. To elucidate the mechanism of neuromelanin synthesis, we studied the formation of melanin in homogenates of human and rat substantia nigra tissue "in vitro". It was found that enzymatic processes accounted for 70% and 90% of the melanin formation in homogenates of human and rat tissue, respectively. The enzymatic synthesis was due to the activity of monoamine oxidase (MAO), since it was prevented by selective inhibitors of this enzyme. Both MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) and MPP+ inhibited melanin formation, probably due to their ability to inhibit MAO. No evidence was found for involvement of cytochrome P-450 monooxigenases, which have been postulated to exist in central catecholaminergic neurons. Proadifen reduced melanin formation, not necessarily because it is an inhibitor of P-450 monooxigenases, but rather as it is also a potent inhibitor of MAO. Some antioxidants like ascorbic acid, but not agents destroying hydrogen peroxide, inhibited melanin formation. The findings suggest that the formation of neuromelanin in the substantia nigra involves MAO and non-enzymatic oxidative processes.

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Section: Measurement Of Melanin Synthesismentioning

confidence: 94%

Neuromelanin synthesis in rat and human substantia nigra

Rabey

Hefti

1990

J Neural Transm Gen Sect

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“…Thus a total distance of 330 ^m, in the 500-Mm column was included in the present study. Additional intensity measurements were taken on brain tissue adjacent to solitarius and on noradrenalinecontaining and noradrenaline-free gelatine standards that were available on the same microscope slide as the brain sections (Lichtensteiger, 1970(Lichtensteiger, ,1971.…”

Section: Microfluorimetrymentioning

confidence: 99%

Environmental events that modify the catecholamine fluorescence of the A2 cell bodies in nucleus tractus solitarii.

Margules¹,

Lichtensteiger²

1978

Journal of Comparative and Physiological Psychology

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The fluorescence intensity of the catecholamine cell bodies of the A2 groupas determined by microfluorimetry-increased significantly due to exposure of the rats to the following environmental events: placement of a rat from the colony cage into a cold (4 °C) room for a period of 10 min, isolation of a rat from the colony for 6-7 days, and satiation of grouped rats by allowing them access to sweetened milk for 15 min. The following events failed to affect the intensity of the cells of A2: reduction of the group colony size from eight to three rats per colony for 6-7 days and presentation of water instead of milk after the rats had experienced 6-7 days of milk satiation. These results indicate that aversive as well as rewarding environmental events activate the catecholamine cells of A2.Within the columnar mass of nucleus tractus solitarii lies a group of catecholamine nerve cells (A2) with unusual biochemical properties. These cells contain phenylethanolamine-JV-methyltransferase (PN-MT; Hokfelt, Fuxe, Goldstein, & Johansson, 1974;Saavedra, Palkovits, Brownstein, & Axelrod, 1974) and are thus capable of synthesizing a secondary catecholamine. Indeed, adrenaline was found in the area of the A2 cells and their terminals, besides noradrenaline and dopamine (Van der Gugten, Palkovits, Versteeg, Palkovits, Van der Gugten, Wijnen, Smeets, & De Jong, 1976). Recent evidence suggests that a biochemical change in the A2 cells may accompany certain forms of stress-related disease, e.g., essential hypertension (Saavedra,

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“…Regular PA has been shown to be protective against oxidative stress on the heart and vascular systems and is important for healthy functioning of the cardiovascular system [9]. Several studies have investigated the effects of habitual PA on heart and lung function and have shown higher rates of function for heart rate response [3,10,11], but not for lung function on average [11,12]. These studies focused on overall PA and have not investigated how specific activities or the volume of PA may influence heart or lung health.…”

Section: Introductionmentioning

confidence: 99%