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Mikko Nikinmaa - One of the best experts on this subject based on the ideXlab platform.
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the lamprey Lampetra fluviatilis erythrocyte morphology ultrastructure major plasma membrane proteins and phospholipids and cytoskeletal organization
Molecular Membrane Biology, 1999Co-Authors: Henry Hagerstrand, Malgorzata Danieluk, Malgorzata Bobrowskahagerstrand, Tim H Holmstrom, Veronika Kraljiglic, Christer Lindqvist, Mikko NikinmaaAbstract:Summary The aim of this study was to characterize the erythrocyte of the lamprey (Lampetra fluviatilis), a primitivevertebrate. The lamprey erythrocyte predominantly has a non-axisymmetric stomatocytelike shape. Ithas a nucleus and a haemoglobin-filled cytosol with a few organelles and vesicular structures. Surprisingly, there is no marginal band of microtubules. Sodium dodecylsulphate polyacrylamide gel electrophoresis followed by Coomassie blue staining of isolated plasma membranes revealed a single band at the level of the human spectrin doublet. Major bands also occurred at approximately 175 kDa and comigrating with human erythrocyte actin (~ 45 kDa). The presence of spectrin, actin and vimentin was shown by immunoblotting. Band 3 protein, the anion exchanger in higher vertebrates, seemed to be highly deficient or lacking, as was also the case with ankyrin. Confocal laser scanning microscopy combined with immunocytochemical methods showed spectrin, actin and vimentin mainly to be localized around the nucleus, from where actin- and vimentinstrands extended out into the cytoplasm. Actin also seemed to be present at the plasma membrane. Phospholipid analyses of plasma membrane preparations showed the presence of the same four major phospholipid groups as in the human erythrocyte, although with higher and lower amounts of phospatidylcholine and sphingomyelin, respectively. The low fluorescein isothiocyanate conjugated annexin V binding, as monitored by flow cytometry, indicated that phosphatidylserine is mainly confined to the inner membrane leaflet in the lamprey erythrocyte plasma membrane.
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Regulation of ion transport across lamprey (Lampetra fluviatilis) erythrocyte membrane by oxygen tension.
The Journal of experimental biology, 1998Co-Authors: Leila V Virkki, A. Salama, Mikko NikinmaaAbstract:We have measured the effects of oxygen tension on the transport of Na+, K+ and Cl- across the erythrocyte membrane of the lamprey Lampetra fluviatilis. The transport of each ion was affected by the oxygen tension of the medium. Hypoxic conditions (PO2 2 kPa) caused an increase in the acidification-induced influx of Na+ via Na+/H+ exchange. The influx of K+ was only slightly affected by the oxygenation of the medium. In contrast, the basal K+ efflux, measured using the radioactive isotope 43K, was markedly reduced by decreasing the oxygen tension of the medium, whereas the K+ flux in hypotonic medium was not affected. Only minor effects of hypoxic conditions on the influx of Cl- were observed in either isotonic or hypotonic conditions (there was a tendency for the isotonic influx to increase) or on the efflux in isotonic conditions. However, deoxygenation caused a marked reduction in the Cl- efflux in hypotonic conditions. The results show that oxygen tension has a marked effect on the pH and volume regulatory transport pathways of lamprey erythrocytes. For K+ and Cl-, the regulation appears to be asymmetric, i.e. influx and efflux are affected differently.
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activation and physiological role of na h exchange in lamprey Lampetra fluviatilis erythrocytes
The Journal of Experimental Biology, 1994Co-Authors: Leila V Virkki, Mikko NikinmaaAbstract:Summary The effects of intracellular acidification, osmotic shrinkage and b-adrenergic stimulation on sodium transport across the membrane of lamprey ( Lampetra fluviatilis) erythrocytes were investigated. Unidirectional ouabain-insensitive sodium flux, measured using radioactive 22 Na, was increased markedly by intracellular acidification, to a lesser extent by osmotic shrinkage and only modestly by b-adrenergic stimulation. Na + /H + exchange was activated in all of these cases. However, net sodium influx (and cell swelling caused by the influx of osmotically obliged water) was seen only in cells subjected to intracellular acidification. In contrast, practically no changes in red cell pH or in water or ion (Na + , K + and Cl 2 ) contents were seen after osmotic shrinkage or badrenergic stimulation. Calculations of the [Na + ]o/[Na + ]i and [H + ]o/[H + ]i ratios across the erythrocyte membrane suggest that the virtual lack of net sodium movements in osmotically shrunken erythrocytes is due to the absence of a driving force for net transport of these ions via the Na + /H + exchange pathway. It also appears that, in physiological conditions, the increase in the activity of the Na + /H + exchanger by badrenergic stimulation is too small to mediate detectable net sodium transport.
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volume and ph regulation in agnathan erythrocytes comparisons between the hagfish myxine glutinosa and the lampreys petromyzon marinus and Lampetra fluviatilis
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 1993Co-Authors: Mikko Nikinmaa, B L Tufts, R G BoutilierAbstract:The responses of hagfish (Myxine glutinosa) and lamprey (Lampetra fluviatilis and Petromyzon marinus) erythrocytes to osmotic swelling in hypoosmotic medium and to acid-base disturbances induced by ammonium chloride prepulse were studied. The erythrocytes of hagfish regulated neither cell volume after osmotic swelling nor intracellular pH after acidification. In contrast, the erythrocytes of lamprey lost potassium and chloride after osmotic swelling, whereby their volume recovered. Furthermore, the red cell pH of lamprey recovered from experimental acidification in a nominally bicarbonate-free medium in the presence of sodium, confirming that the pathway involved is sodium/proton exchange.
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Haemoglobin function in intact Lampetra fluviatilis erythrocytes
Respiration Physiology, 1993Co-Authors: Mikko NikinmaaAbstract:Abstract The red cell pH as a function of oxygen saturation of haemoglobin and the oxygen affinity of haemoglobin as a function of red cell pH in Lampetra fluviatilis were studied at intracellular pH values ranging from 6.7 to 8.0. The maximal increase in red cel pH upon deoxygenation, 0.326 units, was seen when the pH of oxygen-saturated erythrocytes was 7.7, a value corresponding to the red cell pH of resting lampreys. The effect of oxygen saturation on red cell pH was reduced both when the red cell pH was decreased and when it was increased. The haemoglubin-oxygen affinity was strongly pH-dependent, with a Bohr-factor of −1.03. At a high pH (7.67) maintained by lamprey red cells at physiological conditions, the P 50 value was 28.2 Torr. At a pH value (7.33) similar to that of rainbow trout, the P 50 values was 73 Torr. Thus, the high red cell pH in lamprey is required for effective oxygen loading in gills. It also maximizes the apparent cooperatively of oxygen binding.
N P Vesselkin - One of the best experts on this subject based on the ideXlab platform.
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synaptic and electotonic contacts on primary afferent axons in the lamprey Lampetra fluviatilis spinal cord
Journal of Evolutionary Biochemistry and Physiology, 2016Co-Authors: V O Adanina, N P VesselkinAbstract:Distribution of GABA and glycine immunoreactivity was studied in synapses on primary afferent axons of the lamprey Lampetra fluviatilis spinal cord using a double labelling technique. Approximately 25% of synapses exhibit GABA immunoreactivity, while more than 70% are immunoreactive to both neurotransmitters. As in other vertebrates, axo-axonal contacts represent three-component synaptic complexes, the so-called triads, where the immunoreactive terminal make synaptic contact simultaneously with the afferent axon and the dendrite contacting this afferent. Contact zones with gap junction-like cell membrane specializations were found between adjacent afferents suggesting the presence of electrotonic interaction between them. This interaction appears to serve for the synchronization of the afferent flow and represents a structural correlate of the mechanism of rapid interneuronal communication between functionally uniform neurons, which is an important element in the organization of coordinated locomotor acts. Besides, our studies provide evidence that afferent–afferent interaction may be mediated not only electrotonically but also with the aid of chemical synapses. This finding suggests that glutamate-induced depolarization of primary afferents results not only from autoreception but also from the direct effect of glutamate on the afferent’s cell membrane.
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immunoreactivity of synapses on primary afferent axons and sensory neurons in lamprey spinal cord Lampetra fluviatilis
Cell and Tissue Biology, 2008Co-Authors: V O Adanina, A S Adanina, J Reperan, N P VesselkinAbstract:The ultrastructure and immunospecificity of synapses on primary afferents and dorsal sensory cells (DCs) were studied in lamprey (Lampetra fluviatilis) spinal cords. Using the postembedding immunogold method with a combination of antibodies—polyclonal antibodies to glutamate and monoclonal antibodies to gamma-aminobutyric acid (GABA)—the presence of GABA-positive on the primary afferent axons and GABA-and glutamate-immunopositive synapses on the DC somatic membranes have been shown. Thus, it is obvious that sensory information in the lamprey is controlled by both presynaptic inhibition via synapses on the primary afferent axons and by direct synaptic influence on the body of the sensory neuron.
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collaterals and bifurcations of axons of spinal cord motoneurons of the lamprey Lampetra fluviatilis
Journal of Evolutionary Biochemistry and Physiology, 2005Co-Authors: V O Adanina, N P Vesselkin, J ReperantAbstract:Structure of central projections of the motoneuron axons of the spinal cord of the lamprey Lampetra fluviatilis was studied using labeling with horseradish peroxidase in vitro. Axons of the lamprey spinal cord motoneurons were found to have collaterals terminating in ventral columns of the white matter, in which they establish contacts with dendrites of adjacent motoneurons, which can be considered as a substrate of the intermotoneuron interaction. Some axons of motoneurons give bifurcations to two equal branches connected with two neighboring ventral roots, which seems to facilitate propagation of rhythmic activity of locomotor generator in the rostro caudal direction for providing continuous wave of contraction of myotome muscles in the course of undulating movement.
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transmitter sensitivity of primary afferent cells of the lamprey Lampetra fluviatilis spinal cord
Journal of Evolutionary Biochemistry and Physiology, 2002Co-Authors: I V Batueva, N P Vesselkin, James T Buchanan, E I Suderevskaya, E A TsvetkovAbstract:Using dorsal sensory cells (primary afferents) of the spinal cord of the lamprey Lampetra fluviatilis, isolated by an enzymatic-mechanical method, their responses have been studied to application of excitatory amino acids (EAA), glutamate, aspartate, kainate, N-methyl-D-aspartate (NMDA), and of inhibitory amino acids, GABA and glycine, as well as of neuromodulator serotonin (5-hydroxytryptamine, 5-HT). The patch-clamp method was applied to fix either potential or current through membranes of studied cells. It was shown that of all the above substances, only NMDA and kainate could produce in dorsal cells depolarization, input current with maximal amplitude up to 16 nA, and action potential. The main attention in this work was paid to NMDA-current properties. The dose–effect curves were obtained; a blocking effect of specific antagonist of NMDA-receptors, 2-amino-5-phosphonovalerian acid (APV), was shown; passage of Ba ions through Ca2+-channels of dorsal sensory cell membranes at NMDA application was proven. It has been established that in a half of the studied cells under effect of NMDA there is an increase of the maximal amplitude of the potential-activated current through Ca2+-channels, on average, by 22.5 ± 10.5% (n = 21). It was suggested that this variation might be essential for an increase of amount of the transmitter released in synapses formed by processes dorsal sensory cells, while NMDA could be considered a modulator facilitating synaptic activity of these cells.
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Immunohistochemical localization of retinal serotonin cells in the lamprey (Lampetra fluviatilis).
Visual Neuroscience, 1991Co-Authors: Claudine Botteri-versaux, N P Vesselkin, Najet Dalil, Natacha Kenigfest, Jacques Repérant, Jeanine Legros-nguyenAbstract:: Light-microscopic immunocytochemistry was used to study serotonin (5HT)-containing retinal cells in the lamprey (Lampetra fluviatilis). Observations of sections and flatmounted retinas enabled us to distinguish four principal types of 5HT-immunoreactive neurons, on the basis of the localization of their somata and the arrangement of their processes in the inner plexiform layer, (IPL). Type 1 cell bodies (9 micron mean diameter) were numerous and were found in the innermost row of the inner nuclear layer (INL). They sent their processes into a dense plexus in sublamina a of the IPL. Type 2 cell bodies (12 micron mean diameter) were observed near the inner limiting membrane, their processes forming a plexus in sublamina b of the IPL. Most of the type 3 cells were bistratified, their cell bodies (similar in dimension to type 1) were located in the INL and their dendrites projected to both plexuses. Type 4 cell bodies (15 micron mean diameter) were observed in the middle of the IPL and could be compared with the interstitial described elsewhere. Their processes probably ended in the 5HT plexus of sublamina b but because of their sinuous course in the IPL, we could not affirm this fact. Most of 5HT immunoreactive cells were thought to be amacrine cells, but the presence of some thin processes emerging either from the soma or the primary dendrite, principally in type 1 and 2 cells, raises the possibility that some ganglion cells could be 5HT immunoreactive. The organization of the 5HT processes into two plexuses located in sublaminae a and b of the IPL resemble the functional ON and OFF pathway seen in the other vertebrates.
I C Potter - One of the best experts on this subject based on the ideXlab platform.
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circadian rhythms of activity ventilatory frequency and heart rate in the adult river lamprey Lampetra fluviatilis
Journal of Zoology, 2009Co-Authors: P N Claridge, I C Potter, G M HughesAbstract:Activity and the electrocardiogram and respiratory potentials of 17 adult River lampreys, Lampetra fluviatilis, acclimated to 7°± 1°C and a light/dark cycle of 11/13 hours, were recorded throughout the spawning run (November to April). Activity was far greater in the dark in all but the sexually mature animals, reflecting behaviour in the field. A circadian rhythm was also observed in the heart rate during periods of inactivity, and this was correlated with an increase in ventilatory frequency or amplitude. A similar rhythm was not present in the sexually mature animals. Moreover, heart and ventilatory frequencies tended to increase during the spawning run. A whole number ratio between heart rate and ventilatory frequency was seen in only 11 of 425 recordings.
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the estuarine biology of the river lamprey Lampetra fluviatilis in the firth of forth scotland with particular reference to size composition and feeding
Journal of Zoology, 2009Co-Authors: Peter S Maitland, Kenneth H Morris, K East, M P Schoonoord, I C PotterAbstract:Samples collected regularly during 1979, 1980 and 1981 from the intake screens of power stations in the estuary of the River Forth produced data on the estuarine phase in the life cycle of the River lamprey, Lampetra fluviatilis. Recently metamorphosed animals were common during the spring while sexually maturing adults were abundant in the late summer and autumn. These were assumed to be lampreys at the end of their downstream and start of their upstream migrations respectively. The respective sizes of the presumed downstream and upstream migrants were 69–135 mm (0-2-2-8 g) and 200–361 mm (7-0-93-2 g). Smaller numbers of animals of intermediate size were collected during the summer and late autumn. Males were usually the predominant sex with an average of 56–5% of the population in 1980–1981. In all months, the mean weight and with one exception also the mean length, was greater for females than for males. The intestine frequently contained fish remains, especially muscle, bone and scales of clupeids and thus the River lamprey seems to feed mainly on teleosts in this estuary. An analysis of the size of scales in the intestines of lampreys of various body lengths indicates that there is a relationship between the size of host and predator. Comparisons with other studies of Lampetra fluviatilis emphasize the variability that exists in aspects of the biology of this species within and among populations.
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changes in haemopoietic sites during the metamorphosis of the lampreys Lampetra fluviatilis and Lampetra planeri
Journal of Zoology, 2009Co-Authors: Richard Percy, I C PotterAbstract:An investigation has been made in both the parasitic lamprey Lampetra fluviatilis and in its non-parasitic derivative Lampetra planeri of the rate at which the fat column replaces the typhlosole and nephric fold as the principal site of haemopoiesis. In the typhlosole, blood cell formation started to decline prior to the onset of external metamorphosis and had ceased within four weeks of the commencement of transformation. In the nephric fold haemopoiesis continued for several weeks in the region where the larval opisthonephros persisted but was never observed in the newly developing adult kidney. Soon after the onset of external metamorphosis the fat column started to become haemopoietic and later became the main site of blood cell formation. The rate at which the haemopoietic function was transferred from the nephric fold and typhlosole to the fat column was greater in L. fluviatilis than in L. planeri. Since a similar more rapid change in L. fluviatilis has also been found in the switch from larval to adult haemoglobin, the former type of haemoglobins may be produced only in erythrocytes originating in the nephric fold and typhlosole, whereas the latter type may be restricted to cells developed in the fat column. It is also suggested that the functional significance of the alteration in haemopoietic sites is related to changes at metamorphosis in the three regions where blood cell formation occurs.
G M Hughes - One of the best experts on this subject based on the ideXlab platform.
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circadian rhythms of activity ventilatory frequency and heart rate in the adult river lamprey Lampetra fluviatilis
Journal of Zoology, 2009Co-Authors: P N Claridge, I C Potter, G M HughesAbstract:Activity and the electrocardiogram and respiratory potentials of 17 adult River lampreys, Lampetra fluviatilis, acclimated to 7°± 1°C and a light/dark cycle of 11/13 hours, were recorded throughout the spawning run (November to April). Activity was far greater in the dark in all but the sexually mature animals, reflecting behaviour in the field. A circadian rhythm was also observed in the heart rate during periods of inactivity, and this was correlated with an increase in ventilatory frequency or amplitude. A similar rhythm was not present in the sexually mature animals. Moreover, heart and ventilatory frequencies tended to increase during the spawning run. A whole number ratio between heart rate and ventilatory frequency was seen in only 11 of 425 recordings.
J Reperant - One of the best experts on this subject based on the ideXlab platform.
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preoptic fmrf amide like immunoreactive projections to the retina in the lamprey Lampetra fluviatilis
Brain Research, 2009Co-Authors: Monique Medina, J Reperant, R Ward, D Miceli, N B KenigfestAbstract:A centrifugal visual system showing FMRF-amide-like immunoreactivity has been demonstrated in Lampetra fluviatilis by using immunocytochemical and hodological techniques. From 50 to 60 immunoreactive neurons, labelled after contralateral intraocular injection of rhodamine β-isothiocyanate, form a small, clearly defined, nucleus in the lateral neural plate of the magnocellular preoptic nucleus. These cells give rise to immunoreactive axons which have been observed at the base of the nucleus, in the optic chiasma and in the optic nerve, to project into the intermediate plexiform layer of the retina, which separates the layer of internal horizontal cells from the layer of external horizontal cells. This FMRF-amide-like immunoreactive centrifugal visual system is compared to that described in Gnathostomes.
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collaterals and bifurcations of axons of spinal cord motoneurons of the lamprey Lampetra fluviatilis
Journal of Evolutionary Biochemistry and Physiology, 2005Co-Authors: V O Adanina, N P Vesselkin, J ReperantAbstract:Structure of central projections of the motoneuron axons of the spinal cord of the lamprey Lampetra fluviatilis was studied using labeling with horseradish peroxidase in vitro. Axons of the lamprey spinal cord motoneurons were found to have collaterals terminating in ventral columns of the white matter, in which they establish contacts with dendrites of adjacent motoneurons, which can be considered as a substrate of the intermotoneuron interaction. Some axons of motoneurons give bifurcations to two equal branches connected with two neighboring ventral roots, which seems to facilitate propagation of rhythmic activity of locomotor generator in the rostro caudal direction for providing continuous wave of contraction of myotome muscles in the course of undulating movement.
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development of tyrosine hydroxylase immunoreactive systems in the brain of the larval lamprey Lampetra fluviatilis
The Journal of Comparative Neurology, 2002Co-Authors: Jacqueline Pierresimons, J Reperant, Mohamed Mahouche, R WardAbstract:The development of the catecholaminergic system of the brain of the lamprey (Lampetra fluviatilis) was studied with immunocytochemistry in a series of larvae of different sizes by using two different antibodies directed against tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine synthesis. In group 1 larvae (length: 29-54 mm, ages: 8 months to 1.5 years), the only TH-immunoreactive somata observed were located in the caudal wall of the recessus praeopticus (RP) and in the nucleus tuberculi posterioris (NTP). In group 2 larvae (length: 55-80 mm, ages: 1.5-2.5 years), the somata of immunolabeled cells of the NTP give rise to fibers, most of which are ascending and terminate in the corpus striatum. Additional immunoreactive cells are observed in the nucleus praeopticus (NP), which has differentiated, and in the spinal cord. In group 3 larvae (length: 81-110 mm, ages: 2.5-4 years), the spatial distribution of TH-immunoreactive elements (somata, fibers, and terminals) bears many resemblances to that seen in the adult. Immunolabeled cells may be observed in the olfactory bulb, in the nucleus commissurae postopticae (NCP), and in the nucleus dorsalis hypothalami (NDH). Nevertheless, some groups of TH-immunoreactive cells found in the adult are not observed in group 3 larvae; these may appear during the metamorphic phase. By comparative analysis, we show that, in spite of several differences, the spatiotemporal sequence of appearance of TH-immunoreactive cell bodies and fibers in the lamprey presents many similarities to that described in gnathostomes.
