| 1. |
- Elofsson, Rolf, et al.
(författare)
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Is nitric oxide (NO) produced by invertebrate neurons?
- 1993
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Ingår i: NeuroReport. - 1473-558X. ; 4, s. 279-282
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Tidskriftsartikel (refereegranskat)abstract
- NADPH-DIAPHORASE (NADPHd) is known to be identical to nitric oxide (NO) synthase in the mammalian nervous system, and is therefore used as a marker of NO-producing neurones. Using the histochemical reaction for NADPHd, we searched for such neurones in a selection of invertebrates. Special emphasis was given to molluscs. No selective neuronal staining was found in representatives of coelenterates, turbellarians, nematodes and urochordates. In all annelids, arthropods and molluscs examined, with the exception of a chiton, specific neurones were selectively stained. The reaction was particularly strong in pulmonate molluscs where scattered positive neurones were found in various ganglia and clustered symmetrically in the paired buccal ganglia. Biochemical assay of NO synthase in osphradia of the gastropod mollusc Lymnaea stagnalis revealed a formation of citrullin that was inhibited by the specific NO synthase N[omega]-nitro-L-arginine (NO2Arg). Both histochemical and biochemical methods indicate that NO can be used as a signal molecule by specific neurones in advanced invertebrates.
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| 2. |
- Moroz, Leonid, et al.
(författare)
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Serotonin- and FMRFamide-immunoreactive nerve elements in the chiton, Lepidopleurus asellus (Mollusca, Polyplacophora)
- 1994
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 275:2, s. 277-282
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of serotonin-like and FMRFamide-like immunoreactive (5HT-ir and FMRFa-ir, respectively) neurons in the nervous system of the chiton Lepidopleurus asellus (Mollusca, Polyplacophora) was studied using an immunocytochemical technique. The neurons were distributed in characteristic patterns in the central nervous system, the 5HT-ir neurons predominating in the ventral (pedal) cords and FMRFa-ir neurons in the lateral cords. In the body wall including the foot, a tight network of 5HT-ir and FMRFa-ir nerve fibers is found, the former being mostly attributed to the musculature whereas the latter seems to be associated with the blood sinuses. Intraepithelial neurons of both types are abundant in the fore-and hindgut. The presence and general distribution in the central and peripheral nervous system of the 5HT-ir and FMRFa-ir elements seems thus to be similar in simple and advanced molluscs. The relationship between these neurons and their targets in the body also appears to be well conserved in molluscs.
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| 3. |
- Nezlin, Leonid, et al.
(författare)
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Immunolabeled neuroactive substances in the osphradium of the pond snail, Lymnea stagnalis.
- 1994
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 275, s. 269-275
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Tidskriftsartikel (refereegranskat)abstract
- The osphradium of molluscs is assumed to be a sensory organ. The present investigation in Lymnaea stagnalis has established two ultrastructurally different types of dendrites in the sensory epithelium. Cells immunoreactive to leucine-enkephalin and FMRFamide send processes to the sensory epithelium. These neurons of the osphradial ganglion are thus considered to be part of the sensory system, as are methionine-enkephalin-immunoreactive cells in the mantle wall in the vicinity of the osphradium. The complexity of the osphradial ganglion is further demonstrated by serotonin-immunoreactive neurons innervating the muscular coat around the osphradial canal and methionine-enkephalin-immunoreactive cells sending projections to the central nervous system.
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| 4. |
- Nezlin, Leonid P, et al.
(författare)
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Transmitter-specific subsets of sensory elements in the prosobranch osphradium.
- 1994
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Ingår i: Biological Bulletin. - : University of Chicago Press. - 0006-3185 .- 1939-8697. ; 187, s. 174-184
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Tidskriftsartikel (refereegranskat)abstract
- The osphradium is a putative chemosensory organ of aquatic molluscs. Previously, we identified two distinct types of primary sensory neurons in the osphradial ganglion of freshwater pulmonates, one immunoreactive to leucine-enkephalin (LEnk-ir) and another to FMRFamide (FMRFa-ir). In addition, NADPH diaphorase (NADPHd)-positive elements apparently producing nitric oxide (NO) were demonstrated in the organ. In the present study, prosobranch molluscs, which have retained the osphradial sensory neurons within the epithelium, were studied. Both types of peptidergic neurons, as well as NADPHd-positive cells, were found within the epithelium or in a basiepithelial position in the relatively simple osphradium of the mesogastropod Littorina littorea and in the complex, bipectinate osphradium of the neogastropod Buccinum undatum. Similar evidence was also obtained for another mesogastropod, Ampullarius sp. Transmitter-specific sensory cell types like those discovered in the osphradium are also present as single neuroepithelial cells in other organs of the mantle complex in prosobranchs and in the pelecypod Anodonta cygnea. We suggest that evolutionarily conservative, transmitter-specific types of epithelial and neuroepithelial sensory cells predated the osphradium, which developed as the site of their concentration, while retaining characteristic subsets of sensory neurons.
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| 5. |
- Sakharov, Dmitri A, et al.
(författare)
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Patterns of enkephalin immunolabeling in the pulmonate snail Cepea nemoralis and related molluscs.
- 1993
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Ingår i: Brain Research. - 1872-6240. ; 620, s. 114-121
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Tidskriftsartikel (refereegranskat)abstract
- In the land pulmonate snailCepaea nemoralis, immunocytochemical localization of methionine- and leucine-enkephalin-like substances was demonstrated in specific populations of brain neurons. Methionine-enkephalin reactivity is also present in the peripheral nervous system as (i) abundant axonal projections of central neurons to the sole of the foot, and (ii) sparse local neurons of the head and mantle wall. Similar peripheral methionine-enkephalinergic elements were found immunocytochemically in all pulmonates (Helins aspersa, Lymnaea stagnalis) and prosobranchs (Littorina littorea, Acmaea testudinalis) examined and seem therefore conserved among gastropods. Their distribution was different from those of nervous elements labeled by antisera against serotonin and FMRFamide. The chitonLepidopleurus asellus considered to be a more primitive mollusc, had both types of enkephalin-immunoreactive elements in the central nervous system whereas peripheral methionine-enkephalin- immunoreactive elements were lacking. It is suggested on the morphological evidence that enkephalinergic (especially methionine-enkephalinergic) neurons are part of a sensory system mediating analgetic effects in molluscs.
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