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Leonard Maler - One of the best experts on this subject based on the ideXlab platform.
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Stimulus-induced up states in the dorsal pallium of a weakly electric fish
Journal of Neurophysiology, 2015Co-Authors: Stephen Benjamin Elliott, Leonard MalerAbstract:We investigated the response of putative novelty-detecting neurons in the pallium of an electric fish to electrosensory and acoustic stimuli. Extracellular and whole cell patch recordings were made from neurons in the dorsal pallial nucleus (DD) of Apteronotus leptorhynchus. DD neurons were typically quiescent and exhibited hyperpolarized resting membrane potentials. Stimulation induced, with a variable long latency, rapid though transient depolarization and spike discharge. The transition between resting and depolarized/spiking states resembled the transition to Up states seen in mammalian telencephalic neurons.
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differential distribution of sk channel subtypes in the brain of the weakly electric fish Apteronotus leptorhynchus
The Journal of Comparative Neurology, 2008Co-Authors: Lee D Ellis, Leonard Maler, Robert J. DunnAbstract:Calcium signals in vertebrate neurons can induce hyperpolarizing membrane responses through the activation of Ca2+-activated potassium channels. Of these, small conductance (SK) channels regulate neuronal responses through the generation of the medium after-hyperpolarization (mAHP). We have previously shown that an SK channel (AptSK2) contributes to signal processing in the electrosensory system of Apteronotus leptorhynchus. It was shown that for pyramidal neurons in the electrosensory lateral line lobe (ELL), AptSK2 expression selectively decreases responses to low-frequency signals. The localization of all the SK subunits throughout the brain of Apteronotus then became of substantial interest. We have now cloned two additional SK channel subunits from Apteronotus and determined the expression patterns of all three AptSK subunits throughout the brain. In situ hybridization experiments have revealed that, as in mammalian systems, the AptSK1 and 2 channels showed a partially overlapping expression pattern, whereas the AptSK3 channel was expressed in different brain areas. The AptSK1 and 2 channels were the primary subunits found in the major electrosensory processing areas. Immunohistochemistry further revealed distinct compartmentalization of the AptSK1 and 2 channels in the ELL. AptSK1 was localized to the apical dendrites of pyramidal neurons, whereas AptSK2 channels are primarily somatic. The distinct expression patterns of all three AptSK channels may reflect subtype-specific contributions to neuronal function, and the high homology between subtypes from a number of species suggests that the functional roles for each channel subtype are conserved from early vertebrate evolution. J. Comp. Neurol. 507:1964–1978, 2008. © 2008 Wiley-Liss, Inc.
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Regulation of Burst Dynamics Improves Differential Encoding of Stimulus Frequency by Spike Train Segregation
Journal of Neurophysiology, 2007Co-Authors: W. Hamish Mehaffey, Fernando R. Fernandez, Leonard Maler, Ray W TurnerAbstract:Distinguishing between different signals conveyed in a single sensory modality presents a significant problem for sensory processing. The weakly electric fish Apteronotus leptorhynchus use electros...
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Altered sensory filtering and coding properties by synaptic dynamics in the electric sense
Neurocomputing, 2006Co-Authors: Krisztina Szalisznyó, Andre Longtin, Leonard MalerAbstract:This modeling study examines the short-term synaptic plasticity properties of the electrosensory lateral lobe (ELL) afferent pathway in the weakly electric fish, Apteronotus leptorhynchus. We studied the possible functional consequences of a simple phenomenological model of synaptic depression by taking into consideration the available in vivo and in vitro results [N. Berman, L. Maler, Inhibition evoked from primary afferents in the electrosensory lateral line lobe of the weakly electric fish (Apteronotus leptorhynchus), J. Neurophysiol. 80(6) (1998) 3173-3196; M.J. Chacron, B. Doiron, L. Maler, A. Longtin, J. Bastian, Non-classical receptive field mediates switch in a sensory neuron's frequency tuning, Nature 26(424) (2003) 1018-1022]. Filtering and coding properties were examined. We find that simple short-term phenomenological synaptic depression can change steady-state filtering properties and explain how the known physiological constraints influence the coding capabilities of the ELL pyramidal cells via dynamic synaptic transmission.
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Correction: Corrigendum: Non-classical receptive field mediates switch in a sensory neuron's frequency tuning
Nature, 2003Co-Authors: Maurice J Chacron, Brent Doiron, Andre Longtin, Leonard Maler, Joseph BastianAbstract:Nature 423, 77–81 (2003). In this Letter, we inadvertently omitted to give the species name, Apteronotus leptorhynchus (brown ghost knife-fish), of the weakly electric fish used in our study.
Ray W Turner - One of the best experts on this subject based on the ideXlab platform.
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Regulation of Burst Dynamics Improves Differential Encoding of Stimulus Frequency by Spike Train Segregation
Journal of Neurophysiology, 2007Co-Authors: W. Hamish Mehaffey, Fernando R. Fernandez, Leonard Maler, Ray W TurnerAbstract:Distinguishing between different signals conveyed in a single sensory modality presents a significant problem for sensory processing. The weakly electric fish Apteronotus leptorhynchus use electros...
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Model of gamma frequency burst discharge generated by conditional backpropagation.
Journal of Neurophysiology, 2001Co-Authors: Brent Doiron, Ray W Turner, Andre Longtin, Leonard MalerAbstract:Pyramidal cells of the electrosensory lateral line lobe (ELL) of the weakly electric fish Apteronotus leptorhynchus have been shown to produce oscillatory burst discharge in the γ-frequency range (...
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distribution of omega conotoxin gvia binding sites in teleost cerebellar and electrosensory neurons
The Journal of Comparative Neurology, 1996Co-Authors: Y Tharani, G A Thurlow, Ray W TurnerAbstract:: The distribution of omega-Conotoxin GVIA (CgTx) binding sites was used to localize putative N-type Ca2+ channels in an electrosensory cerebellar lobule, the eminentia granularis pars posterior, and in the electrosensory lateral line lobe of a gymnotiform teleost (Apteronotus leptorhynchus). The binding sites for CgTx revealed by an anti-CgTx antibody had a consistent distribution on somatic and dendritic membranes of specific cell types in both structures. The distribution of CgTx binding was unaffected by co-incubation with nifedipine or AgaToxin IVA, blocking agents for L- and P-type Ca2+ channels, respectively. Incubation with CgTx in the presence of varying levels of extracellular Ca2+ altered the number but not the cell types exhibiting immunolabel. A punctate immunolabel was detected on somatic membranes of granule and stellate cell interneurons in both the eminentia granularis pars posterior and the electrosensory lateral line lobe. Punctate CgTx binding sites were also present on spherical cell somata and on the large presynaptic terminals of primary afferents that terminate on spherical cells in the electrosensory lateral line lobe. No label was detected in association with distal dendritic membranes of any cell class, or with parallel fibers in the respective molecular layers. Binding sites for CgTx in the eminentia granularis are consistent with the established role for N-type Ca2+ channels in cell migrations, an activity which is known to persist in this layer in adult Apteronotus. The distribution of labeled stellate cells with respect to topographic maps in the electrosensory lateral line lobe further suggest that N-type Ca2+ channels are expressed in relation to functional activity across these sensory maps.
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localization of nicotinamide adenine dinucleotide phosphate diaphorase activity in electrosensory and electromotor systems of a gymnotiform teleost Apteronotus leptorhynchus
The Journal of Comparative Neurology, 1995Co-Authors: Ray W Turner, Leonid L MorozAbstract:The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity was determined in electrosensory and electromotor systems of the weakly electric gymnotiform teleost Apteronotus leptorhynchus as an indicator of putative nitric oxide synthase-containing cells. NADPH-d activity was detected in electroreceptors and in afferent nerves of both ampullary and type I and type II tuberous organs. All cell bodies within the anterior lateral line nerve ganglion were positive for NADPH-d activity, as were the primary afferent axons and termination fields in the medullary electrosensory lateral line lobe. In the corpus cerebelli and valvula cerebelli, NADPH-d label was present in Purkinje cell somata, mossy fiber synaptic glomeruli, granule cells, and parallel fibers. In the midbrain, NADPH-d activity was apparent in layer VIIIB of the torus semicircularis dorsalis and in electrosensory laminae of the optic tectum. NADPH-d was particularly associated with diencephalic electrosensory and electromotor nuclei, including the prepacemaker nucleus, the nucleus subelectrosensorius, and the central posterior nucleus of the thalamus. Intense NADPH-d activity was present in pacemaker and relay cells of the medullary pacemaker nucleus but was absent from a novel class of smaller cells in this structure. Relay cell axons and spinal electromotor neurons and their axons within the electric organ were positive for NADPH-d activity. These results indicate that putative nitric oxide synthase-containing neurons in Apteronotus are localized preferentially to electrosensory and electromotor structures, suggesting a role for nitric oxide in determining the activity of cells involved in detecting or generating weakly electric fields. © 1995 Wiley-Liss, Inc.
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Localization of nicotinamide adenine dinucleotide phosphate‐diaphorase activity in electrosensory and electromotor systems of a gymnotiform teleost, Apteronotus leptorhynchus
The Journal of Comparative Neurology, 1995Co-Authors: Ray W Turner, Leonid L MorozAbstract:The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity was determined in electrosensory and electromotor systems of the weakly electric gymnotiform teleost Apteronotus leptorhynchus as an indicator of putative nitric oxide synthase-containing cells. NADPH-d activity was detected in electroreceptors and in afferent nerves of both ampullary and type I and type II tuberous organs. All cell bodies within the anterior lateral line nerve ganglion were positive for NADPH-d activity, as were the primary afferent axons and termination fields in the medullary electrosensory lateral line lobe. In the corpus cerebelli and valvula cerebelli, NADPH-d label was present in Purkinje cell somata, mossy fiber synaptic glomeruli, granule cells, and parallel fibers. In the midbrain, NADPH-d activity was apparent in layer VIIIB of the torus semicircularis dorsalis and in electrosensory laminae of the optic tectum. NADPH-d was particularly associated with diencephalic electrosensory and electromotor nuclei, including the prepacemaker nucleus, the nucleus subelectrosensorius, and the central posterior nucleus of the thalamus. Intense NADPH-d activity was present in pacemaker and relay cells of the medullary pacemaker nucleus but was absent from a novel class of smaller cells in this structure. Relay cell axons and spinal electromotor neurons and their axons within the electric organ were positive for NADPH-d activity. These results indicate that putative nitric oxide synthase-containing neurons in Apteronotus are localized preferentially to electrosensory and electromotor structures, suggesting a role for nitric oxide in determining the activity of cells involved in detecting or generating weakly electric fields. © 1995 Wiley-Liss, Inc.
Gunther K H Zupanc - One of the best experts on this subject based on the ideXlab platform.
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indeterminate body growth and lack of gonadal decline in the brown ghost knifefish Apteronotus leptorhynchus an organism exhibiting negligible brain senescence
Canadian Journal of Zoology, 2014Co-Authors: Iulian Ilieş, Ruxandra F Sirbulescu, Gunther K H ZupancAbstract:The brown ghost knifefish (Apteronotus leptorhynchus (Ellis in Eigenmann, 1912)) is the only vertebrate organism identified thus far that exhibits negligible brain senescence. The present study exa...
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Temperature Dependence of the Electric Organ Discharge in Weakly Electric Fish
Exploring Animal Behavior in Laboratory and Field, 2007Co-Authors: Gunther K H Zupanc, Gerhard Engler, J.r. Banks, Robert C. BeasonAbstract:Publisher Summary This chapter emphasizes a laboratory experiment, its procedure and results, of temperature dependence of the electric organ discharge in weakly electric fish. Some species of cartilaginous and bony fish have developed specialized sensory systems through which they can sense electric signals originating from physical or biological sources, even if these signals are of such low amplitude that we can detect them only with sensitive and highly sophisticated equipment. Many of these fish have, in the course of evolution, developed their own specialized organs that produce electric discharges, known by the name of electric organ discharge (EOD). On the basis of the voltage of these discharges, electric fish are divided into two groups—strongly electric and weakly electric. In both Eigenmannia and Apteronotus, the EOD is sexually dimorphic. Male Apteronotus leptorhynchus typically discharge, within the species-specific range (approximately 500-1000 hertz at a temperature of 27˚C) at higher frequencies than females. In Eigenmannia sp., this sexual dimorphism is reversed. In this species, females discharge, within the species-specific range (240-600 hertz at a temperature of 25˚C at higher frequencies than males. It is likely that this information is used for recognition of potential sexual mates and for electro-communication in each genus. As demonstrated in the lab exercise, however, a “male” EOD can be transformed into a “female” EOD (and vice versa) by changing the ambient temperature.
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Molecular cloning and pharmacological characterization of a somatostatin receptor subtype in the gymnotiform fish Apteronotus albifrons.
General and comparative endocrinology, 1999Co-Authors: Gunther K H Zupanc, Sandra Siehler, Eugenia M.c. Jones, Klaus Seuwen, Hiroto Furuta, Daniel Hoyer, Hideki YanoAbstract:Abstract The actions of the various forms of somatostatin (SRIF), including those of the tetradecapeptide SRIF14, are mediated by specific receptors. In mammals, five subtypes of SRIF receptors, termed sst1–5, have been cloned. Using a combination of reverse transcriptase-polymerase chain reaction and genomic library screening in the gymnotiform fish Apteronotus albifrons, a gene encoding the first-known nonmammalian SRIF receptor has been isolated. The deduced amino acid sequence displays 59% identity with the human sst3 receptor protein; hence, the gene is termed “Apteronotus sst3.” The predicted protein consists of 494 amino acid residues exhibiting a putative seven-transmembrane domain topology typical of G protein-coupled receptors. A signal corresponding to the Apteronotus sst3 receptor was detected in brain after amplification of poly(A)+-RNA by reverse transcriptase-polymerase chain reaction, but not by Northern blot analysis or in situ hybridization, suggesting a low level of expression. Membranes prepared from CCL39 cells stably expressing the Apteronotus sst3 receptor gene bound [125I][Leu8, d -Trp22,125 I-Tyr25]SRIF28 with high affinity and in a saturable manner (Bmax = 4470 fmol/mg protein; pKD = 10.5). SRIF14 and various synthetic SRIF receptor agonists produced a dose-dependent inhibition of radioligand binding, with the following rank order of potency: SRIF14 ≈ SRIF28 > BIM 23052 > octreotide > BIM 23056. Under low stringency conditions, an Apteronotus sst3 probe hybridized to multiple DNA fragments in HindIII or EcoRI digests of A. albifrons DNA, indicating that the Apteronotus sst3 receptor is a member of a larger family of Apteronotus SRIF receptors.
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Expression of somatostatin in neurons of the central posterior/prepacemaker nucleus projecting to the preglomerular nucleus: immunohistochemical evidence for a non-synaptic function
Neuroscience Letters, 1997Co-Authors: Gunther K H Zupanc, Ingrid Horschke, Thomas StrohAbstract:In the diencephalon of the weakly electric gymnotiform fish Apteronotus leptorhynchus, part of the central posterior/prepacemaker nucleus innervates the preglomerular nucleus. A minor population of these neurons expresses immunoreactivity against somatostatin, as has been shown by combining peptide immunohistochemistry with an in vitro tract-tracing technique. In contrast to the expectation, however, this neuropeptide does not appear to be transported along the axons to the projection site, as somatostatin-like immunoreactivity could not be detected in the preglomerular nucleus. It is, therefore, likely that somatostatin expressed in these neurons exerts a non-synaptic function in the region of the central posterior/prepacemaker nucleus itself.
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apoptosis in the cerebellum of adult teleost fish Apteronotus leptorhynchus
Developmental Brain Research, 1996Co-Authors: Jurgen Soutschek, Gunther K H ZupancAbstract:Abstract While involvement of programmed cell death (apoptosis) in embryogenesis is well established, only very little is known about this phenomenon in later stages of development. Based primarily on indirect evidence, it has been proposed that during postembryonic development of fish cell death does not occur. We have re-addressed this issue by examining the gymnotiform fish Apteronotus leptorhynchus. This teleost exhibits a high degree of proliferative activity in the brain during adulthood. Most of these cells are born in the cerebellum, where they differentiate, migrate into specific target regions, and are added to the population of already existing cerebellar cells. By applying morphological criteria and an in situ technique for the detection of DNA fragmentation (a feature characteristic of apoptotic cells), we show here that a large number of cerebellar cells undergo apoptosis. The density of apoptocis cells in significantly higher in the granule cell layers of the various subdivisions of the cerebellum than in the corresponding molecular layers. This finding is consistent with previous observations indicating a drastic reduction in areal density of newborn cells within these granule cell layers in a period 4–7 weeks after their generation. In the granule cell layers of two cerebellar subdivisions, the corpus cerebelli and the valvula cerebelli pars medialis, the areal density of apoptotic cells displays a significant negative correlation with body weight, thus pointing to a decrease in the number of apoptotic events with age. The results of our investigation provide clear evidence for the existence of apoptosis during adulthood in fish and underline the significance of this process in the postembryonic development of the brain.
Leonid L Moroz - One of the best experts on this subject based on the ideXlab platform.
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localization of nicotinamide adenine dinucleotide phosphate diaphorase activity in electrosensory and electromotor systems of a gymnotiform teleost Apteronotus leptorhynchus
The Journal of Comparative Neurology, 1995Co-Authors: Ray W Turner, Leonid L MorozAbstract:The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity was determined in electrosensory and electromotor systems of the weakly electric gymnotiform teleost Apteronotus leptorhynchus as an indicator of putative nitric oxide synthase-containing cells. NADPH-d activity was detected in electroreceptors and in afferent nerves of both ampullary and type I and type II tuberous organs. All cell bodies within the anterior lateral line nerve ganglion were positive for NADPH-d activity, as were the primary afferent axons and termination fields in the medullary electrosensory lateral line lobe. In the corpus cerebelli and valvula cerebelli, NADPH-d label was present in Purkinje cell somata, mossy fiber synaptic glomeruli, granule cells, and parallel fibers. In the midbrain, NADPH-d activity was apparent in layer VIIIB of the torus semicircularis dorsalis and in electrosensory laminae of the optic tectum. NADPH-d was particularly associated with diencephalic electrosensory and electromotor nuclei, including the prepacemaker nucleus, the nucleus subelectrosensorius, and the central posterior nucleus of the thalamus. Intense NADPH-d activity was present in pacemaker and relay cells of the medullary pacemaker nucleus but was absent from a novel class of smaller cells in this structure. Relay cell axons and spinal electromotor neurons and their axons within the electric organ were positive for NADPH-d activity. These results indicate that putative nitric oxide synthase-containing neurons in Apteronotus are localized preferentially to electrosensory and electromotor structures, suggesting a role for nitric oxide in determining the activity of cells involved in detecting or generating weakly electric fields. © 1995 Wiley-Liss, Inc.
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Localization of nicotinamide adenine dinucleotide phosphate‐diaphorase activity in electrosensory and electromotor systems of a gymnotiform teleost, Apteronotus leptorhynchus
The Journal of Comparative Neurology, 1995Co-Authors: Ray W Turner, Leonid L MorozAbstract:The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity was determined in electrosensory and electromotor systems of the weakly electric gymnotiform teleost Apteronotus leptorhynchus as an indicator of putative nitric oxide synthase-containing cells. NADPH-d activity was detected in electroreceptors and in afferent nerves of both ampullary and type I and type II tuberous organs. All cell bodies within the anterior lateral line nerve ganglion were positive for NADPH-d activity, as were the primary afferent axons and termination fields in the medullary electrosensory lateral line lobe. In the corpus cerebelli and valvula cerebelli, NADPH-d label was present in Purkinje cell somata, mossy fiber synaptic glomeruli, granule cells, and parallel fibers. In the midbrain, NADPH-d activity was apparent in layer VIIIB of the torus semicircularis dorsalis and in electrosensory laminae of the optic tectum. NADPH-d was particularly associated with diencephalic electrosensory and electromotor nuclei, including the prepacemaker nucleus, the nucleus subelectrosensorius, and the central posterior nucleus of the thalamus. Intense NADPH-d activity was present in pacemaker and relay cells of the medullary pacemaker nucleus but was absent from a novel class of smaller cells in this structure. Relay cell axons and spinal electromotor neurons and their axons within the electric organ were positive for NADPH-d activity. These results indicate that putative nitric oxide synthase-containing neurons in Apteronotus are localized preferentially to electrosensory and electromotor structures, suggesting a role for nitric oxide in determining the activity of cells involved in detecting or generating weakly electric fields. © 1995 Wiley-Liss, Inc.
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Localization of nicotinamide adenine dinucleotide phosphate‐diaphorase activity in electrosensory and electromotor systems of a gymnotiform teleost, Apteronotus leptorhynchus
The Journal of comparative neurology, 1995Co-Authors: Ray W Turner, Leonid L MorozAbstract:The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity was determined in electrosensory and electromotor systems of the weakly electric gymnotiform teleost Apteronotus leptorhynchus as an indicator of putative nitric oxide synthase-containing cells. NADPH-d activity was detected in electroreceptors and in afferent nerves of both ampullary and type I and type II tuberous organs. All cell bodies within the anterior lateral line nerve ganglion were positive for NADPH-d activity, as were the primary afferent axons and termination fields in the medullary electrosensory lateral line lobe. In the corpus cerebelli and valvula cerebelli, NADPH-d label was present in Purkinje cell somata, mossy fiber synaptic glomeruli, granule cells, and parallel fibers. In the midbrain, NADPH-d activity was apparent in layer VIIIB of the torus semicircularis dorsalis and in electrosensory laminae of the optic tectum. NADPH-d was particularly associated with diencephalic electrosensory and electromotor nuclei, including the prepacemaker nucleus, the nucleus subelectrosensorius, and the central posterior nucleus of the thalamus. Intense NADPH-d activity was present in pacemaker and relay cells of the medullary pacemaker nucleus but was absent from a novel class of smaller cells in this structure. Relay cell axons and spinal electromotor neurons and their axons within the electric organ were positive for NADPH-d activity. These results indicate that putative nitric oxide synthase-containing neurons in Apteronotus are localized preferentially to electrosensory and electromotor structures, suggesting a role for nitric oxide in determining the activity of cells involved in detecting or generating weakly electric fields.
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localization of nicotinamide adenine dinucleotide phosphate diaphorase activity in electrosensory and electromotor systems of a gymnotiform teleost Apteronotus leptorhynchus
The Journal of Comparative Neurology, 1995Co-Authors: Ray W Turner, Leonid L MorozAbstract:The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity was determined in electrosensory and electromotor systems of the weakly electric gymnotiform teleost Apteronotus leptorhynchus as an indicator of putative nitric oxide synthase-containing cells. NADPH-d activity was detected in electroreceptors and in afferent nerves of both ampullary and type I and type II tuberous organs. All cell bodies within the anterior lateral line nerve ganglion were positive for NADPH-d activity, as were the primary afferent axons and termination fields in the medullary electrosensory lateral line lobe. In the corpus cerebelli and valvula cerebelli, NADPH-d label was present in Purkinje cell somata, mossy fiber synaptic glomeruli, granule cells, and parallel fibers. In the midbrain, NADPH-d activity was apparent in layer VIIIB of the torus semicircularis dorsalis and in electrosensory laminae of the optic tectum. NADPH-d was particularly associated with diencephalic electrosensory and electromotor nuclei, including the prepacemaker nucleus, the nucleus subelectrosensorius, and the central posterior nucleus of the thalamus. Intense NADPH-d activity was present in pacemaker and relay cells of the medullary pacemaker nucleus but was absent from a novel class of smaller cells in this structure. Relay cell axons and spinal electromotor neurons and their axons within the electric organ were positive for NADPH-d activity. These results indicate that putative nitric oxide synthase-containing neurons in Apteronotus are localized preferentially to electrosensory and electromotor structures, suggesting a role for nitric oxide in determining the activity of cells involved in detecting or generating weakly electric fields.
Sabine Blähser - One of the best experts on this subject based on the ideXlab platform.
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Development, during ontogenetic development of gymnotids, of substance p expression in tuberous organs (electroreceptors)
Comptes Rendus De L Academie Des Sciences Serie Iii-sciences De La Vie-life Sciences, 1992Co-Authors: Mourad Bensouilah, Sabine Blähser, Jean-pierre DenizotAbstract:: The evolution of the neuropeptidic expression of Substance P has been investigated with immunohistochemistry in the cutaneous electroreceptors, tuberous organs, during ontogenetic development of Apteronotus leptorhynchus. In the present data, antiSP antiserum has been applied to serial sections of Apteronotus leptorhynchus larvae obtained from several egg layings. Larvae were taken during development from hatching up to one hundred days old. SP immunoreactivity appeared just after hatching, in the epidermal zones which give rise to cutaneous sense organs. Four days after hatching, the tuberous organs are differentiated and immunoreactivity was observed in these organs, in both sensory cells and accessory cells. From day 30 after hatching, there was a regular decrease in the number of tuberous organs showing labelled accessory cells, and one hundred days later only 8% of tuberous organs had immunoreactive accessory cells. The adult accessory cells were no longer labelled with anti-SP antiserum. The results showed that in Apteronotus leptorhynchus, the epidermal structures which give rise to the cutaneous sensory organs were immunoreactive at a very early stage of development; this suggests that SP could have an effect upon their differentiation.
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Immunohistochemical identification of substance P in cutaneous sensory organs (electroreceptors) of gymnotid teleost fish
Cell and Tissue Research, 1991Co-Authors: Mourad Bensouilah, Jean-pierre Denizot, Sabine BlähserAbstract:The distribution of the neuropeptide substance P, which is considered to be a neurotransmitter or neuromodulator of the central nervous system, has been studied in the cutaneous electroreceptor organs (tuberous and ampullary organs) of 3 species of gymnotid fish: Apteronotus leptorhynchus, Eigenmannia virescens and Sternopygus sp. Immunohistochemical data have revealed that substance P is never present in the afferent fibers but is specifically localized in the electroreceptors of the three species examined. Substane P immunoreactivity is strictly localized in the sensory cells of the ampullary organs of all three species and in those of the tuberous organs of Apteronotus leptorhynchus and Sternopygus sp. In contrast, weak substance P immunoreactivity was observed only in certain tuberous sensory cells of Eigenmannia. Substance P immunoreactivity was also found in the accessory cells of certain organs: it was detected in the two types of accessory cells of the tuberous organs of Eigemmannia virescens, in the accessory cells type 2 of the tuberous organs of Sternopygus sp., and in all accessory cells of ampullary organs of Sternopygus sp. and Apteronotus leptorhynchus. In Sternopygus sp., positive staining was only evident if the substance P antibody was used at low concentration. Immunoreactivity for substance P in the sensory cells suggests that it has a transmitter or modulator function in these electroreceptors; the presence of substance P in the accessory cells remains to be explained.