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E Syková - One of the best experts on this subject based on the ideXlab platform.

  • Extracellular space volume changes in the rat spinal cord produced by nerve stimulation and peripheral injury.
    Brain research, 1991
    Co-Authors: J Svoboda, E Syková
    Abstract:

    Double-barrelled potassium and tetramethylammonium-sensitive microelectrodes were used in diffusion studies with tetramethylammonium ions, which remain essentially extracellular during the measurements. Activity-related changes in the extracellular space (ECS) volume fraction (alpha), ECS tortuosity (lambda) and the dynamics of the ECS volume changes were examined in the spinal dorsal horns of rats. The alpha and lambda in L4 and L5 segments of unstimulated rats were alpha = 0.24 +/- 0.01 (i.e. ECS occupied 24 +/- 1% of the total spinal cord volume) and lambda = 1.54 +/- 0.04 (mean +/- S.D. of mean, n = 21). The values were not significantly different throughout the dorsal horn. Repetitive electrical stimulation of peripheral nerves at 3-100 Hz increased extracellular potassium concentration [( K+]e) and ECS volume in Rexed laminae III-V by 15.8 +/- 2.7% (n = 5). After the end of stimulation, when the [K+]e decreased below the original baseline (K+ undershoot), the ECS volume decreased by 20-45%. The magnitude and duration of ECS volume decrease were positively related to the stimulation frequency and duration. The ECS volume decrease was maximal at 2-10 min after the stimulation had been discontinued, and it returned to the prestimulation values in 15-40 min. The ECS volume decreased by 20-50% after injury of the ipsilateral hind paw evoked either by subcutaneous injection of turpentine (n = 5), or by thermal injury (n = 6). The maximal changes were found in Rexed laminae III-V, 5-10 min after injection of turpentine and 10-25 min after thermal injury, and persisted for more than 120 min and 30 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  • Extracellular space volume changes in the rat spinal cord produced by nerve stimulation and peripheral injury
    Brain Research, 1991
    Co-Authors: J Svoboda, E Syková
    Abstract:

    Abstract Double-barrelled potassium and tetramethylammonium-sensitive microelectrodes were used in diffusion studies with tetramethylammonium ions, which remain essentially extracellular during the measurements. Activity-related changes in the extracellular space (ECS) volume fraction (α), ECS tortuosity (γ) and the dynamics of the ECS volume changes were examined in the spinal dorsal horns of rats. The α and γ in L4 and L5 segments of unstimulated rats werea = 0.24 ± 0.01 (i.e. ECS occupied24 ± 1% of the total spinal cord volume) andγ = 1.54 ± 0.04 (mean ± S.D. of mean, n = 21). The values were not significantly different throughout the dorsal horn. Repetitive electrical stimulation of peripheral nerves at 3-100 Hz increased extracellular potassium concentration ([K+]e) and ECS volume in Rexed laminae III-V by15.8 ± 2.7% (n = 5). After the end of stimulation, when the [K+]e decreased below the original baseline (K+ undershoot), the ECS volume decreased by 20–45%. The magnitude and duration of ECS volume decrease were positively related to the stimulation frequency and duration. The ECS volume decrease was maximal at 2–10 min after the stimulation had been discontinued, and it returned to the prestimulation values in 15–40 min. The ECS volume decreased by 20–50% after injury of the ipsilateral hind paw evoked either by subcutaneous injection of turpentine (n = 5), or by thermal injury (n = 6). The maximal changes were found in Rexed laminae III–V, 5–10 min after injection of turpentine and 10–25 min after thermal injury, and persisted for more than 120 min and 30 min, respectively. The tortuosity of the ECS was not significantly altered by stimulation or injury. Our measurements indicate that the dynamic changes in the spinal cord ECS volume accompany transmembrane ionic shifts during and long after neural activity which had been evoked by peripheral stimulation or injury.

J Svoboda - One of the best experts on this subject based on the ideXlab platform.

  • Extracellular space volume changes in the rat spinal cord produced by nerve stimulation and peripheral injury.
    Brain research, 1991
    Co-Authors: J Svoboda, E Syková
    Abstract:

    Double-barrelled potassium and tetramethylammonium-sensitive microelectrodes were used in diffusion studies with tetramethylammonium ions, which remain essentially extracellular during the measurements. Activity-related changes in the extracellular space (ECS) volume fraction (alpha), ECS tortuosity (lambda) and the dynamics of the ECS volume changes were examined in the spinal dorsal horns of rats. The alpha and lambda in L4 and L5 segments of unstimulated rats were alpha = 0.24 +/- 0.01 (i.e. ECS occupied 24 +/- 1% of the total spinal cord volume) and lambda = 1.54 +/- 0.04 (mean +/- S.D. of mean, n = 21). The values were not significantly different throughout the dorsal horn. Repetitive electrical stimulation of peripheral nerves at 3-100 Hz increased extracellular potassium concentration [( K+]e) and ECS volume in Rexed laminae III-V by 15.8 +/- 2.7% (n = 5). After the end of stimulation, when the [K+]e decreased below the original baseline (K+ undershoot), the ECS volume decreased by 20-45%. The magnitude and duration of ECS volume decrease were positively related to the stimulation frequency and duration. The ECS volume decrease was maximal at 2-10 min after the stimulation had been discontinued, and it returned to the prestimulation values in 15-40 min. The ECS volume decreased by 20-50% after injury of the ipsilateral hind paw evoked either by subcutaneous injection of turpentine (n = 5), or by thermal injury (n = 6). The maximal changes were found in Rexed laminae III-V, 5-10 min after injection of turpentine and 10-25 min after thermal injury, and persisted for more than 120 min and 30 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  • Extracellular space volume changes in the rat spinal cord produced by nerve stimulation and peripheral injury
    Brain Research, 1991
    Co-Authors: J Svoboda, E Syková
    Abstract:

    Abstract Double-barrelled potassium and tetramethylammonium-sensitive microelectrodes were used in diffusion studies with tetramethylammonium ions, which remain essentially extracellular during the measurements. Activity-related changes in the extracellular space (ECS) volume fraction (α), ECS tortuosity (γ) and the dynamics of the ECS volume changes were examined in the spinal dorsal horns of rats. The α and γ in L4 and L5 segments of unstimulated rats werea = 0.24 ± 0.01 (i.e. ECS occupied24 ± 1% of the total spinal cord volume) andγ = 1.54 ± 0.04 (mean ± S.D. of mean, n = 21). The values were not significantly different throughout the dorsal horn. Repetitive electrical stimulation of peripheral nerves at 3-100 Hz increased extracellular potassium concentration ([K+]e) and ECS volume in Rexed laminae III-V by15.8 ± 2.7% (n = 5). After the end of stimulation, when the [K+]e decreased below the original baseline (K+ undershoot), the ECS volume decreased by 20–45%. The magnitude and duration of ECS volume decrease were positively related to the stimulation frequency and duration. The ECS volume decrease was maximal at 2–10 min after the stimulation had been discontinued, and it returned to the prestimulation values in 15–40 min. The ECS volume decreased by 20–50% after injury of the ipsilateral hind paw evoked either by subcutaneous injection of turpentine (n = 5), or by thermal injury (n = 6). The maximal changes were found in Rexed laminae III–V, 5–10 min after injection of turpentine and 10–25 min after thermal injury, and persisted for more than 120 min and 30 min, respectively. The tortuosity of the ECS was not significantly altered by stimulation or injury. Our measurements indicate that the dynamic changes in the spinal cord ECS volume accompany transmembrane ionic shifts during and long after neural activity which had been evoked by peripheral stimulation or injury.

Lars Edvinsson - One of the best experts on this subject based on the ideXlab platform.

  • Tracing neural connections to pain pathways with relevance to primary headaches.
    Cephalalgia, 2011
    Co-Authors: Lars Edvinsson
    Abstract:

    Background: Symptoms associated with primary headaches are linked to cranial vascular activity and to the central nervous system (CNS). Review: The central projections of sensory nerves from three cranial vessels are described in order to further understand pain mechanisms involved in primary headaches. Tracers that label small and large calibre primary afferent fibres revealed similar distributions for the central terminations of sensory nerves in the superficial temporal artery, superior sagittal sinus and middle meningeal artery. The sensory nerve fibres from the vessels pass through both the trigeminal and rostral cervical spinal nerves and terminate in the ventrolateral part of the C1-C3 dorsal horns and the caudal and interpolar divisions of the spinal trigeminal nucleus. The C-fibre terminations were located mainly in the superficial layers (Rexed laminae I and II), and the Aδ-fibres terminated in the deep layers (laminae III and IV). The rostral projections from the ventrolateral C1-C2 dorsal horn revealed terminations in the medial and lateral parabrachial nuclei, the cuneiform nucleus, the periaqueductal gray, the deep mesencephalic nucleus, the thalamic posterior nuclear group and its triangular part, and the thalamic ventral posteromedial nucleus. The terminations in the pons and midbrain were predominately bilateral, whereas those in the thalamus were confined to the contralateral side. Conclusions: The observations, done in rats with the understanding that similar trigeminovascular organization exists in man, reveal vascular projections into the brainstem and some aspects of the central regions putatively involved in the central processing of noxious craniovascular signals. (Less)

N. V. Pavlova - One of the best experts on this subject based on the ideXlab platform.

  • Morphofunctional Studies of the Involvement of the Serotoninergic System in the Control of Postural and Locomotor Functions
    Neuroscience and Behavioral Physiology, 2014
    Co-Authors: Yu. P. Gerasimenko, T. R. Moshonkina, N. V. Pavlova, Elena Tomilovskaya, Inessa Kozlovskaya
    Abstract:

    Various transmitter systems, including the serotoninergic, influence the locomotor behavior of animals. Studies have shown that the spinal cord, deprived of supraspinal control, has mechanisms able to induce locomotor activity in the hindlimbs and that the afferent system can trigger these mechanisms. Behavioral experiments on rats with complete transection of the spinal cord showed that pharmacological suppression of the serotoninergic system leads to suppression of motor activity associated with activation of support reactions (locomotor training). Histological studies did not identify any effect of activating support reactions on neuron survival or the distribution of synaptic contacts in spinal cord segments L2–L4. However, suppression of the serotoninergic system has been shown to lead to changes in cells in laminae 1–3 of the dorsal horns and in Rexed lamina 7, along with redistribution of synaptic contacts in Rexed laminae 1–4 in the dorsal horns of the spinal cord.

  • Serotoninergic system morphofunctional aspects in control of postural and locomotion function
    Rossiiskii fiziologicheskii zhurnal imeni I.M. Sechenova, 2012
    Co-Authors: Gerasimenko Iup, T. R. Moshonkina, N. V. Pavlova
    Abstract:

    Different mediator systems including serotoninergic one can influence animal's locomotor behavior. It has been shown that the spinal cord in the absence of supraspinal control is able to induce the locomotor activity in hindlimbs and afferent system can activate this mechanism. In behavioral studies on the rats with complete transection of the spinal cord it has been demonstrated that the pharmacological blocking of serotoninergic system results in depression of motor activity mediated by activation of support reactions. Histological studies did not reveal any effects of activation of support reactions on the safety of neurons as well as on the distribution of synaptic contacts within L2-L4 spinal segments. At the same time it has been shown that blockade of the serotoninergic system results in alterations of cells located in 1-3 laminae of dorsal horns, and in 7 Rexed's lamina as well as in redistribution of synaptic contacts in 1-4 Rexed laminae of the spinal cord dorsal horns.

  • Morphofunctional characteristics of the lumbar enlargement of the spinal cord in rats
    Neuroscience and Behavioral Physiology, 2008
    Co-Authors: E. G. Gilerovich, T. R. Moshonkina, N. V. Pavlova, Yu. P. Gerasimenko, E. A. Fedorova, T. T. Shishko, V. A. Otellin
    Abstract:

    The topography of the lumbar enlargement of the spinal cord in rats was studied; an immunohistochemical method was used to determine the distribution of synaptophysin — a membrane protein of synaptic vesicles. Synaptophysin-immunoreactive structures were detected in the gray matter of all Rexed laminae, around most neurons and in the neuropil. Previously undescribed subpial synaptic contacts were detected immunohistochemically in the white matter and confirmed by electron microscopy. A non-myelinated component of the corticospinal tract, including axonal varicosities and synaptic contacts, was observed in the dorsal part of the white matter of the lumbar enlargement of the spinal cord.

  • Morpho-functional characterictic of rat lumbar spinal cord enlargement
    Morfologiia (Saint Petersburg Russia), 2007
    Co-Authors: E. G. Gilerovich, N. V. Pavlova, E. A. Fedorova, Gerasimenko Iup
    Abstract:

    Topography and the distribution of synaptophysin-immunoreactive structures were studied in the rat lumbar spinal cord enlargement. Synaptophysin (synaptic vesicle marker) was found in the gray matter of all Rexed laminae around most neurons and in neuropil. Subpial synaptic contacts, that were not described previously, were found in the white matter by immunohistochemistry and their presence was confirmed by electron microscopy. They were localized directly beneath the astrocyte processes, that cover the spinal cord externally. In the dorsal portion of the white matter within the lumbar spinal cord enlargement, the unmyelinated synaptophysin-immunoreactive component of pyramidal tract was detected which included axonal varicosities and synaptic contacts.

S. P. Hunt - One of the best experts on this subject based on the ideXlab platform.

  • DISTRIBUTION OF GABA(A) RECEPTOR SUBUNIT MESSENGER-RNAS IN RAT LUMBAR SPINAL-CORD
    Molecular Brain Research, 1991
    Co-Authors: William Wisden, Al Gundlach, Peter H. Seeburg, Ea Barnard, S. P. Hunt
    Abstract:

    The expression of various GABA(A) receptor subunit mRNAs (alpha-1, alpha-2, alpha-3, alpha-5, beta-1, beta-2, beta-3, gamma-2, delta) was studied in the adult rat lumbar spinal cord by in situ hybridization. Of these, only alpha-2, alpha-3, beta-3 and gamma-2 mRNAs are expressed at significant levels. The alpha-3, beta-3 and gamma-2 transcripts are present in many neurons throughout the Rexed laminae, whereas the alpha-2 mRNA is restricted to motor neurons and adjacent cells.

  • Distribution of GABAA receptor subunit mRNAs in rat lumbar spinal cord
    Brain research. Molecular brain research, 1991
    Co-Authors: William Wisden, Al Gundlach, Eric A. Barnard, Peter H. Seeburg, S. P. Hunt
    Abstract:

    The expression of various GABAA receptor subunit mRNAs (α1, α2, α3, α5, β1, β2, β3, γ2, δ) was studied in the adult rat lumbar spinal cord by in situ hybridization. Of these, only α2, α3, β3 and γ2 mRNAs are expressed at significant levels. The α3, β3 and γ2 transcripts are present in many neurons throughout the Rexed laminae, whereas the α2 mRNA is restricted to motor neurons and adjacent cells.