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- Jankowska, Elzbieta, et al.
(författare)
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Morphology of interneurones in pathways from group II muscle afferents in sacral segments of the cat spinal cord.
- 1993
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Ingår i: The Journal of comparative neurology. - : Wiley. - 0021-9967. ; 337:3, s. 518-28
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of 12 sacral interneurones with peripheral input from group II muscle afferents was analyzed after intracellular injection of horseradish peroxidase (HRP). The neurones were located in Rexed's laminae III-V overlying the pudendal (Onuf's) motor nucleus. The interneurones had medium sized elongated somata and dendrites projecting radially. All of the interneurones were funicular neurones and fell into two categories depending on whether their axons ran within the dorsal part of the lateral funiculus (DLF; n = 7) or within the ventral funiculus, or the ventral part of the lateral funiculus (VF or VLF; n = 4). The latter were located more rostrally. Within the DLF similar proportions of stem axons and secondary axonal branches descended and ascended. Within the VF and VLF all of the axons ascended. Collaterals of axons running in the DLF arborized primarily within the dorsal horn and the intermediate zone; none were found to approach the motor nuclei. In contrast, collaterals of axons running in the VF/VLF arborized in both the intermediate zone and the ventral horn and passed close to the motor nuclei. We conclude that sacral interneurones with group II input are morphologically nonhomogenous and that only those located most rostrally might have direct actions upon motoneurones. Both the axonal projections and the input (from group II but not from group I muscle afferents and from skin afferents) of sacral interneurones indicate that they are homologous to dorsal horn group II interneurones in the midlumbar segments. They appear, however, to form part of more local neuronal networks than their midlumbar counterparts.
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| 2. |
- 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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