| 1. |
- Ekström, Peter, et al.
(författare)
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Electron microscopic analysis of S‐antigen‐ and serotonin‐immuoreactive neural and sensory elements in the photosensory pineal organ of the salmon
- 1990
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967. ; 292:1, s. 73-82
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Tidskriftsartikel (refereegranskat)abstract
- Photoreceptor cells in the pineal complex of poikilothermic vertebrates are regarded as homologous with the neuroendocrine pinealocytes in the mammalian pineal organ. They possess an indolamine metabolism, and they contain a number of substances that are immunochemically similar to phototransduction‐related proteins otherwise found in photoreceptors of the lateral eye retina. Using correlative light and electron microscopic pre‐embedding immunocytochemistry, we have identified photosensory and neural elements that are immunoreactive with specific antisera against serotonin (5‐hydroxytryptamine) and the 48 kDa soluble protein S‐antigen (arrestin). One type of serotonin‐immunoreactive (5HTir) photoreceptor cell was identified. This was characterized by a short basal pole, into which an immunoreactive (postsynaptic?) element protruded. Two types of ‐antigen‐immunoreactive (SAir) photoreceptor cells were observed, one characterized by a short basal pole, similar to that of the 5HTir photoreceptors and the other characterized by a long, extensively branching basal pole. In addition, two types of neurons bearing no morphological specializations typical of photoreceptor cells were SAir: bipolar neurons and multipolar neurons. These were often situated dorsally in the pineal organ. The results indicate an emergence of multiple lines of photoreceptor‐derived “pinealocytes” either early in phylogeny, or independently in different taxa. The results are discussed in relation to current theories of pineal evolution.
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| 2. |
- Holmqvist, Bo I., et al.
(författare)
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Galanin‐like immunoreactivity in the brain of teleosts : Distribution and relation to substance P, vasotocin, and isotocin in the atlantic salmon (Salmo salar)
- 1991
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967. ; 306:3, s. 361-381
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Tidskriftsartikel (refereegranskat)abstract
- The presence of galanin‐like substances and their relation to substance P‐, vasotocin‐, and isotocin‐immunoreactive neurons and fibers in the brain of teleosts was investigated with immunohistochemical methods. Two specific antisera against synthetic porcine galanin (GAL) revealed cell bodies and fibers in the brain of four different teleost species (Salmo salar, Carassius carassius, Gasterosteus aculeatus, and Anguilla anguilla). In all four species the main location of galanin immunoreactivity was in the hypothalamo‐pituitary region. A detailed study of the distribution of galanin immunoreactivity in S. salar showed that galanin immunoreactive (GALir) perikarya were present in the nucleus preopticus periventricularis, an area that may be compared to the supraoptic nucleus in mammals, and in the nucleus lateralis tuberis, a nucleus involved in pituitary control in fishes that may be compared with the arcuate nucleus in mammals, GALir perikarya were found also in the nucleus recessus lateralis and in the nucleus recessus posterior. Numerous GALir fibers were present in the telencephalon and diencephalon, whereas only small numbers of fibers were found in the brainstem. In contrast to the situation in mammals, no GALir perikarya were observed in the brainstem areas corresponding to the noradrenergic locus coeruleus and serotonergic raphe nuclei in S. salar. We did not find any coexistence of GALir substances with arginine vasotocin or isotocin in neurosecretory neurons, as has been shown for galanin with the mammalian counterparts vasopressin and oxytocin. Also, the galanin‐like substance(s) and their structurally closest related peptide family, the tachykinins, belong to separate neuronal systems in teleosts. The presence of GALir neurons in brain areas known to be involved in pituitary control, and a massive GALir innervation of the pituitary, strongly indicate a role for galanin‐like substances in pituitary control also in teleosts. Furthermore, the presence of extrahypothalamic GALir fibers suggests involvement of galanin‐like substances in other brain functions in teleosts. In conclusion, there are general similarities between teleosts and mammals concerning the distribution of galanin‐like substances. However, there seem to be substantial differences in their distribution relative to functionally related peptides within the hypothalamo‐pituitary system. Whereas galanin appears to be colocalized and released together with vasopressin and oxytocin in mammals, in teleosts the homologous substances are contained within different sets of neurons that innervate the same target, the pituitary.
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| 3. |
- Honkanen, Tapio, et al.
(författare)
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An immunocytochemical study of the olfactory projections in the three‐spined stickleback, Gasterosteus aculeatus, L
- 1990
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967. ; 292:1, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of olfactory fibers in the brain of the three‐spined stickleback was visualized by means of immunohistochemistry. The labeling of the olfactory fibers was produced by serum containing antibodies against somatostatin‐14. Olfactory fibers were observed entering the olfactory bulbs, where they terminated in the glomerular layer or collected into fascicles that coursed through the bulbs into the telencephalon without participating in the formation of the glomerules. In the telencephalon the fascicles, which belonged to the medial olfactory tract, formed two fiber systems: ventral descending fibers and dorsal descending fibers. The ventral descending fibers could be followed through the ventral telencephalon to the vicinity of the lateral tuberal nucleus. The dorsal descending fibers coursed via the anterior commissure to the posterior part of the telencephalon. Part of the postcommissural fibers of the dorsal descending system coursed to the posterior zone of the area dorsalis telencephali while others left the telencephalon via the medial forebrain bundle and could be followed to the periventricular hypothalamus. Some axons formed synaptic contacts with unlabeled cell bodies in the nucleus of the terminal nerve which, in this species, is situated immediately behind the bulbs. In addition, an extensive terminal field associated with the dorsal descending fibers was found in the ventromedial aspects of the telencephalon. It is unlikely that the labeling represents immunoreactive somatostin‐14 because: 1) the labeling persisted after the absorption of the antiserum with synthetic somatostatin‐14; 2) antiserum against somatostatin‐14 from another manufacturer did not have this labeling property; and 3) the production of the absorbable labeling depended on the choice of fixative whereas the production of the unabsorbable labeling did not.
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| 4. |
- Vecino, Elena, et al.
(författare)
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Distribution of met‐enkephalin, leu‐enkephalin, substance P, neuropeptide Y, FMRFamide, and serotonin immunoreactivities in the optic tectum of the Atlantic salmon (Salmo salar L.)
- 1990
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967. ; 299:2, s. 229-241
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of the neuropeptides methionine‐ and leucine‐enkephalins, substance P, FMRFamide, neuropeptide Y, and vasoactive intestinal peptide, as well as the biogenic amine serotonin was studied in the optic tectum of the Atlantic salmon by means of immunocytochemistry. Peroxidase‐antiperoxidase and indirect immunofluorescence methods were used to compare the differential laminar distribution of each of these substances. Nine parts of the optic tectum were selected for analysis on frontal sections: median, dorsolateral, and ventrolateral areas at rostral, medial, and caudal levels. Methionine‐ and leucine‐enkephalin immunoreactive fibers were found in discrete sublayers in the following strata: stratum opticum, stratum fibrosum et griseum superficiale, stratum griseum centrale, stratum, and album centrale. Most of the substance P‐, serotonin‐, and vasoactive intestinal peptide‐immunoreactive fibers were found in the stratum album centrale, whereas the FMRFamide‐ and neuropeptide Y‐immunoreactive fibers were more or less randomly distributed within most of the strata of the optic tectum. Neuropeptide Y‐immunoreactive cell bodies were located in the stratum periventriculare. We suggest an extrinsic origin for most of the immunoreactive fibers observed in the optic tectum, except for the neuropeptide Y‐immunoreactive fibers that probably originate in the periventricular neurons. Although retinal peptidergic input to the optic tectum has been proposed in other vertebrates, there is no evidence that any of the neuropeptidelike or serotonin immunoreactive fibers in the optic tectum of the salmon should be of retinal origin. Differences and similarities with the distribution of neuropeptides in the optic tectum in representatives of other vertebrate classes are discussed.
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