| 1. |
- Elofsson, Rolf, et al.
(författare)
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A catecholaminergic neuron connecting the first two optic neuropiles (lamina ganglionaris and medulla externa) of the crayfish Pacifastacus leniusculus
- 1977
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 182, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- The crustacean optic neuropiles, the lamina ganglionaris and especially the medulla externa, show a specific pattern of green fluorescence with the fluorescence histochemical method of Falck-Hillarp. Normally, only the terminals and the cell bodies fluoresce, but in reserpine-treated animals exogenous catecholamines are taken up by the whole adrenergic neuron and are thus visualized as a whole. Incubating crayfish optic neuropiles in dopamine or α-methylnoradrenaline after reserpine treatment demonstrated a tangential neuron connecting the lamina and the medulla externa. The morphology of this tangential neuron differs from the two types of tangential neurons, Tan1 and Tan2, previously characterized with Golgi techniques. The catecholaminergic neuron thus constitutes a third tangential neuron type.
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| 2. |
- Elofsson, Rolf, et al.
(författare)
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Catcholaminergic salivary glands in Gammarus pulex (Crustacea, Amphipoda): An electron microscopic and microspectrofluorometric study
- 1978
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Ingår i: Journal of Ultrastructure Research. - 0022-5320. ; 64, s. 14-22
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Tidskriftsartikel (refereegranskat)abstract
- The type of gland (salivary gland) described here for the amphipod Gammarus pulex belongs to the tegumental glands, which have different structural characteristics. The present type, called rosette gland, is common in some crustaceans and is located in the ventral half of the head. The functional unit is a lobule of gland cells with a central-draining duct. Ducts from groups of lobules conjoin and terminate on the body surface at different points around and in the mouth and mouth parts. With the fluorescence histochemical method of Falck and Hillarp, specific green fluorescence was discerned centrally in the lobules and was confined to the gland cells. The spectral characteristics of the fluorescence, as revealed by microspectrofluorometric analysis, indicated either a mixture of dopamine and a presumed new catechol compound or the presence of two tautomeric forms either of dopamine or of a new catechol compound. Evidence of new catechol compounds with similar spectral characteristics has previously been found in the sensory cells of some invertebrates. The fluorescence distribution within the lobule coincides with the presence, ultrastructurally, of large dense vesicles in the gland cells. These dense vesicles occur in the predominant cell type, also characterized by a smooth endoplasmic reticulum. The other cell type in the lobules differs ultrastructurally by possessing a rough endoplasmic reticulum and a different vesicle type. No innervation of the salivary gland was perceived.
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| 3. |
- Elofsson, Rolf, et al.
(författare)
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Catecholaminergic innervation of muscles in the hindgut of crustaceans
- 1978
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 189, s. 257-266
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Tidskriftsartikel (refereegranskat)abstract
- The crustacean species Pacifastacus leniusculus and Gammarus pulex were investigated by electron microscopy in a search for possible neuromuscular junctions in the hindgut, which has a rich supply of catecholaminergic fibres. True neuromuscular synapses were found in both species between nerve terminals containing dense-core vesicles (80–110 nm in diam.) and muscle fibres. We suggest that the dense-core vesicle terminals contain a catecholamine, and this is supported by ultrahistochemical tests for monoamines. Two types of junctions are found: one in which the nerve terminal is embedded in the muscle cell (both species) and one in which protrusions from the muscle cell meet nerve terminals (Pacifastacus). Gammarus pulex, which has only circular muscles in the hindgut, has only catecholaminergic innervation, whereas Pacifastacus leniusculus has circular and longitudinal muscles both with at least two types of innervation.
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| 4. |
- Elofsson, Rolf, et al.
(författare)
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Evidence for new catecholamines or related amino acids in some invertebrate neurons
- 1977
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 182, s. 525-536
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Tidskriftsartikel (refereegranskat)abstract
- In certain sensory neurons of many different invertebrate species, including the sea anemones. Metridium senile and Tealia felina and the crustacean Anemia salina, fluorophores are formed during the course of the fluorescent histochemical technique of Falck-Hillarp. The presumed catecholamine nature of the neuronal fluorogenic compound was investigated by microspectrofluorometry, and the spectral characteristics of the fluorescence in the taxonomically different species was found to be very similar (excitation maximum at 375 nm with a smaller peak or shoulder at 330 nm and sometimes a shoulder in the spectrum at 410 nm; emission maximum at 475 nm). The emission maximum coincides with that of the catecholamines and DOPA (475 nm). The excitation maximum (375 nm) directly after formaldehyde treatment, however, differs from that of the catecholamines and DOPA (410 nm), but is similar to the excitation maximum displayed by these catechol derivatives at acid pH. The spectral characteristics of the fluorophore in the sensory cells might therefore theoretically be explained by an acid pH in the cells. This seems improbable, however, and it is suggested that the phenomenon is due to the presence of unknown catechol derivatives. Analyses of the pH-dependent spectral changes indicate that the presumed catechol derivative in Tealia felina is β-hydroxylated, whereas that in Anemia salina is not.
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| 5. |
- Myhrberg, Harry, et al.
(författare)
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Selective uptake of exogenous catecholamines into nerve fibers in crustaceans. A fluorescense histochemical investigation
- 1979
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Ingår i: Comparative Biochemistry and Physiology. Part C: Comparative Pharmacology & Toxicology. - : Elsevier BV. - 0742-8413 .- 0306-4492. ; 62, s. 14-151
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Tidskriftsartikel (refereegranskat)abstract
- 1. The depletion and uptake of exogenous catecholamines into the central nervous system of crustaceans were investigated by the Falck & Hillarp histochemical fluorescence method. 2. Depletion experiments with reserpine showed an almost complete disappearance of the fluorescence in the optic ganglia and the brain. 3. Some monoaminergic fibres in the photocerebrum and medulla terminals appeared to be reserpine-resistant. 4. Dopamine and α-methylnoradrenaline were actively taken up in vitro by monoaminergic structures after pretreatment with reserpine. 5. Benztropine and ouabain failed to inhibit this uptake. 6. 6-Hydroxydopamine had no effect on the fluorescence of the catecholaminergic neurones.
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