Spike activity and histofluorescence correlated in the giant dopamine neuron of Planorbis corneus

Lichtensteiger, W.; Felix, Dominik; Hefti, Franz

doi:10.1016/0006-8993(79)90104-5

Cited by 15 publications

(3 citation statements)

References 19 publications

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“…The use of ionomycin to stimulate the cell body effectively demonstrates that changes in intracellular calcium are required for the observed exocytosis of dopamine. Another possibility is that the bursting pattern observed in our data correlates to the individual action potentials or membrane potential oscillations that have been observed to take place with a pacemaker-like manner or bursting firing pattern for molluscan cells and mammalian cells (Lichtensteiger et al, 1979;Arshavsky et al, 1988;Marcus and Carew, 1991;Jagadeesh et al, 1992;Kukuljan, 1992;Cardozo, 1993). This behavior is likely to result from interactions between the intact Time (minutes) 25 30…”

Section: Discussionmentioning

confidence: 55%

“…The physiological calcium levels are higher for invertebrate systems compared to mammalian systems. The dissection procedure and the identification of the dopamine containing neuron were described previously (Berry, 1972;Logan and Cottrell, 1975;Loker et al, 1975;Osborne et al, 1975;Lichtensteiger, 1979;Chien et al, 1988;Steiner and Felix, 1989). Snail shells were smashed before snails were pinned with the ventral side uppermost in a wax-filled Petri dish.…”

Section: Methodsmentioning

confidence: 99%

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Observation and quantitation of exocytosis from the cell body of a fully developed neuron in Planorbis corneus

et al. 1995

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We have discovered a neuronal system that releases neurotransmitter via exocytosis from the cell body. In the large dopamine cell of the pond snail Planorbis corneus, depolarization induces rhythmic release of dopamine from the cell body. When a stimulant is applied extracellularly or intracellularly in situ to the cell body, transient dopamine concentration packets that appear in a bursting pattern are observed. Dopamine release is calcium dependent and release is on the time scale expected for exocytosis (2 to 4 msec rise times). Quantitation of individual events reveals an average of 818,000 molecules per exocytotic event. As many as 89,000 individual exocytotic events have been observed following a single stimulation of one cell. Neurotransmitter exocytosis from the neuronal cell body appears to represent an alternative form of neurocommunication to synaptic transmission.

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Section: Discussionmentioning

confidence: 55%

Section: Methodsmentioning

confidence: 99%

Observation and quantitation of exocytosis from the cell body of a fully developed neuron in Planorbis corneus

et al. 1995

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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: 95%

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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Endogenous ?-melanotropin and central dopamine systems in physical and psychological stress

Monnet

Lichtensteiger

1981

Exp Brain Res

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Spike activity and histofluorescence correlated in the giant dopamine neuron of Planorbis corneus

Cited by 15 publications

References 19 publications

Observation and quantitation of exocytosis from the cell body of a fully developed neuron in Planorbis corneus

Observation and quantitation of exocytosis from the cell body of a fully developed neuron in Planorbis corneus

Neuromelanin synthesis in rat and human substantia nigra

Endogenous ?-melanotropin and central dopamine systems in physical and psychological stress

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