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Abstract
The frontal lobe is crucial and contributes to controlling truncal motion, postural responses, and maintaining equilibrium and locomotion. The rich repertoire of frontal gait disorders gives some indication of this complexity. For human walking, it is necessary to simultaneously achieve at least two tasks, such as maintaining a bipedal upright posture and locomotion. Particularly, postural control plays an extremely significant role in enabling the subject to maintain stable gait behaviors to adapt to the environment. To achieve these requirements, the frontal cortex (1) uses cognitive information from the parietal, temporal, and occipital cortices, (2) creates plans and programs of gait behaviors, and (3) acts on the brainstem and spinal cord, where the core posture-gait mechanisms exist. Moreover, the frontal cortex enables one to achieve a variety of gait patterns in response to environmental changes by switching gait patterns from automatic routine to intentionally controlled and learning the new paradigms of gait strategy via networks with the basal ganglia, cerebellum, and limbic structures. This chapter discusses the role of each area of the frontal cortex in behavioral control and attempts to explain how frontal lobe controls walking with special reference to postural control.
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Affiliation(s)
- Kaoru Takakusaki
- Department of Physiology, Division of Neuroscience, Asahikawa Medical University, Asahikawa, Japan.
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Zeng W, Yang F, Shen WL, Zhan C, Zheng P, Hu J. Interactions between central nervous system and peripheral metabolic organs. SCIENCE CHINA. LIFE SCIENCES 2022; 65:1929-1958. [PMID: 35771484 DOI: 10.1007/s11427-021-2103-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/07/2022] [Indexed: 02/08/2023]
Abstract
According to Descartes, minds and bodies are distinct kinds of "substance", and they cannot have causal interactions. However, in neuroscience, the two-way interaction between the brain and peripheral organs is an emerging field of research. Several lines of evidence highlight the importance of such interactions. For example, the peripheral metabolic systems are overwhelmingly regulated by the mind (brain), and anxiety and depression greatly affect the functioning of these systems. Also, psychological stress can cause a variety of physical symptoms, such as bone loss. Moreover, the gut microbiota appears to play a key role in neuropsychiatric and neurodegenerative diseases. Mechanistically, as the command center of the body, the brain can regulate our internal organs and glands through the autonomic nervous system and neuroendocrine system, although it is generally considered to be outside the realm of voluntary control. The autonomic nervous system itself can be further subdivided into the sympathetic and parasympathetic systems. The sympathetic division functions a bit like the accelerator pedal on a car, and the parasympathetic division functions as the brake. The high center of the autonomic nervous system and the neuroendocrine system is the hypothalamus, which contains several subnuclei that control several basic physiological functions, such as the digestion of food and regulation of body temperature. Also, numerous peripheral signals contribute to the regulation of brain functions. Gastrointestinal (GI) hormones, insulin, and leptin are transported into the brain, where they regulate innate behaviors such as feeding, and they are also involved in emotional and cognitive functions. The brain can recognize peripheral inflammatory cytokines and induce a transient syndrome called sick behavior (SB), characterized by fatigue, reduced physical and social activity, and cognitive impairment. In summary, knowledge of the biological basis of the interactions between the central nervous system and peripheral organs will promote the full understanding of how our body works and the rational treatment of disorders. Thus, we summarize current development in our understanding of five types of central-peripheral interactions, including neural control of adipose tissues, energy expenditure, bone metabolism, feeding involving the brain-gut axis and gut microbiota. These interactions are essential for maintaining vital bodily functions, which result in homeostasis, i.e., a natural balance in the body's systems.
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Affiliation(s)
- Wenwen Zeng
- Institute for Immunology, and Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, 100084, China. .,Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China. .,Beijing Key Laboratory for Immunological Research on Chronic Diseases, Beijing, 100084, China.
| | - Fan Yang
- The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
| | - Wei L Shen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Cheng Zhan
- Department of Hematology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China. .,National Institute of Biological Sciences, Beijing, 102206, China. .,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China.
| | - Peng Zheng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400042, China. .,Institute of Neuroscience and the Collaborative Innovation Center for Brain Science, Chongqing Medical University, Chongqing, 400016, China. .,Chongqing Key Laboratory of Neurobiology, Chongqing, 400016, China.
| | - Ji Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
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Bud Craig AD. Central neural substrates involved in temperature discrimination, thermal pain, thermal comfort, and thermoregulatory behavior. HANDBOOK OF CLINICAL NEUROLOGY 2018; 156:317-338. [PMID: 30454598 DOI: 10.1016/b978-0-444-63912-7.00019-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A phylogenetically novel pathway that emerged with primate encephalization is described, which conveys high-fidelity cutaneous thermosensory activity in "labeled lines" to a somatotopic map in the dorsal posterior insular cortex. It originates in lamina I of the superficial dorsal horn and ascends by way of the lateral spinothalamic tract and a distinct region in posterolateral thalamus. It evolved from the homeostatic sensory activity that represents the physiologic (interoceptive) condition of the body and drives the central autonomic network, which underlies all affective feelings from the body. Accordingly, human discriminative thermal sensations are accompanied by thermally motivated behaviors and thermal feelings of comfort or discomfort (unless neutral), which evidence suggests are associated with activity in the insular, cingulate, and orbitofrontal cortices, respectively. Yet, the substrates for thermoregulatory behavior have not been established, and several strong candidates (including the hypothalamus and the bed nucleus of the stria terminalis) are discussed. Finally, the neural underpinnings for relationships between thermal affect and social feelings (warm-positive/cold-negative) are addressed, including the association of hyperthermia with clinical depression.
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Affiliation(s)
- Arthur D Bud Craig
- Atkinson Research Laboratory, Barrow Neurological Institute, Phoenix, AZ, United States.
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Kanbar R, Stornetta RL, Guyenet PG. Sciatic nerve stimulation activates the retrotrapezoid nucleus in anesthetized rats. J Neurophysiol 2016; 116:2081-2092. [PMID: 27512023 DOI: 10.1152/jn.00543.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 08/03/2016] [Indexed: 11/22/2022] Open
Abstract
Retrotrapezoid nucleus (RTN) neurons sustain breathing automaticity. These neurons have chemoreceptor properties, but their firing is also regulated by multiple synaptic inputs of uncertain function. Here we test whether RTN neurons, like neighboring presympathetic neurons, are excited by somatic afferent stimulation. Experiments were performed in Inactin-anesthetized, bilaterally vagotomized, paralyzed, mechanically ventilated Sprague-Dawley rats. End-expiratory CO2 (eeCO2) was varied between 4% and 10% to modify rate and amplitude of phrenic nerve discharge (PND). RTN and presympathetic neurons were recorded extracellularly below the facial motor nucleus with established criteria. Sciatic nerve stimulation (SNstim, 1 ms, 0.5 Hz) slightly increased blood pressure (6.6 ± 1.6 mmHg) and heart rate and, at low eeCO2 (<5.5%), entrained PND. Ipsi- and contralateral SNstim produced the known biphasic activation of presympathetic neurons. SNstim evoked a similar but weaker biphasic response in up to 67% of RTN neurons and monophasic excitation in the rest. At low eeCO2, RTN neurons were silent and responded more weakly to SNstim than at high eeCO2 RTN neuron firing was respiratory modulated to various degrees. The phasic activation of RTN neurons elicited by SNstim was virtually unchanged at high eeCO2 when PND entrainment to the stimulus was disrupted. Thus RTN neuron response to SNstim did not result from entrainment to the central pattern generator. Overall, SNstim shifted the relationship between RTN firing and eeCO2 upward. In conclusion, somatic afferent stimulation increases RTN neuron firing probability without altering their response to CO2. This pathway may contribute to the hyperpnea triggered by nociception, exercise (muscle metabotropic reflex), or hyperthermia.
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Affiliation(s)
- Roy Kanbar
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese American University, Byblos, Lebanon; and
| | - Ruth L Stornetta
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Patrice G Guyenet
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, Virginia
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Watanabe N, Miyazaki S, Mukaino Y, Hotta H. Effect of gentle cutaneous stimulation on heat-induced autonomic response and subjective pain intensity in healthy humans. J Physiol Sci 2012; 62:343-50. [PMID: 22614394 PMCID: PMC10717059 DOI: 10.1007/s12576-012-0210-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 05/03/2012] [Indexed: 02/01/2023]
Abstract
The present study examined whether touch influences the autonomic responses and subjective pain intensity induced by noxious heat stimulation in humans. Heart rate and digital pulse wave were recorded. Heat stimulation was applied to the right plantar foot before, during, and after touch. Subjective pain intensity was evaluated using a visual analog scale (VAS). Touch was applied over the right medial malleolus for 10 min. Two types of touch were employed in a cross-over double-blinded randomized manner. When touch was applied with a soft elastomer brush, heat-induced autonomic responses attenuated significantly, while VAS scores were unchanged. In contrast, touch with a flat disc was ineffective for any measurement. Participants hardly perceived a difference in the texture of the touching materials. The present study result suggests there are mechanisms in conscious humans where some sort of touch inhibits nociceptive transmission into autonomic reflex pathways independent of sensation and cognition.
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Affiliation(s)
- Nobuhiro Watanabe
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015 Japan
| | - Shogo Miyazaki
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015 Japan
- Department of Acupuncture and Moxibustion, Faculty of Health Care, Teikyo Heisei University, 2-51-4 Higashi-ikebukuro, Toshima-ku, Tokyo, 170-8445 Japan
| | - Yoshito Mukaino
- Faculty of Sports and Health Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180 Japan
| | - Harumi Hotta
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015 Japan
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Panneton WM, Gan Q, Livergood RS. A trigeminoreticular pathway: implications in pain. PLoS One 2011; 6:e24499. [PMID: 21957454 PMCID: PMC3177822 DOI: 10.1371/journal.pone.0024499] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 08/11/2011] [Indexed: 01/18/2023] Open
Abstract
Neurons in the caudalmost ventrolateral medulla (cmVLM) respond to noxious stimulation. We previously have shown most efferent projections from this locus project to areas implicated either in the processing or modulation of pain. Here we show the cmVLM of the rat receives projections from superficial laminae of the medullary dorsal horn (MDH) and has neurons activated with capsaicin injections into the temporalis muscle. Injections of either biotinylated dextran amine (BDA) into the MDH or fluorogold (FG)/fluorescent microbeads into the cmVLM showed projections from lamina I and II of the MDH to the cmVLM. Morphometric analysis showed the retrogradely-labeled neurons were small (area 88.7 µm(2)±3.4) and mostly fusiform in shape. Injections (20-50 µl) of 0.5% capsaicin into the temporalis muscle and subsequent immunohistochemistry for c-Fos showed nuclei labeled in the dorsomedial trigeminocervical complex (TCC), the cmVLM, the lateral medulla, and the internal lateral subnucleus of the parabrachial complex (PBil). Additional labeling with c-Fos was seen in the subnucleus interpolaris of the spinal trigeminal nucleus, the rostral ventrolateral medulla, the superior salivatory nucleus, the rostral ventromedial medulla, and the A1, A5, A7 and subcoeruleus catecholamine areas. Injections of FG into the PBil produced robust label in the lateral medulla and cmVLM while injections of BDA into the lateral medulla showed projections to the PBil. Immunohistochemical experiments to antibodies against substance P, the substance P receptor (NK1), calcitonin gene regulating peptide, leucine enkephalin, VRL1 (TPRV2) receptors and neuropeptide Y showed that these peptides/receptors densely stained the cmVLM. We suggest the MDH- cmVLM projection is important for pain from head and neck areas. We offer a potential new pathway for regulating deep pain via the neurons of the TCC, the cmVLM, the lateral medulla, and the PBil and propose these areas compose a trigeminoreticular pathway, possibly the trigeminal homologue of the spinoreticulothalamic pathway.
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Affiliation(s)
- W Michael Panneton
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri, United States of America.
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Cordero-Erausquin M, Allard S, Dolique T, Bachand K, Ribeiro-da-Silva A, De Koninck Y. Dorsal horn neurons presynaptic to lamina I spinoparabrachial neurons revealed by transynaptic labeling. J Comp Neurol 2009; 517:601-15. [DOI: 10.1002/cne.22179] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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The spinothalamic system targets motor and sensory areas in the cerebral cortex of monkeys. J Neurosci 2009; 29:14223-35. [PMID: 19906970 DOI: 10.1523/jneurosci.3398-09.2009] [Citation(s) in RCA: 254] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Classically, the spinothalamic (ST) system has been viewed as the major pathway for transmitting nociceptive and thermoceptive information to the cerebral cortex. There is a long-standing controversy about the cortical targets of this system. We used anterograde transneuronal transport of the H129 strain of herpes simplex virus type 1 in the Cebus monkey to label the cortical areas that receive ST input. We found that the ST system reaches multiple cortical areas located in the contralateral hemisphere. The major targets are granular insular cortex, secondary somatosensory cortex and several cortical areas in the cingulate sulcus. It is noteworthy that comparable cortical regions in humans consistently display activation when subjects are acutely exposed to painful stimuli. We next combined anterograde transneuronal transport of virus with injections of a conventional tracer into the ventral premotor area (PMv). We used the PMv injection to identify the cingulate motor areas on the medial wall of the hemisphere. This combined approach demonstrated that each of the cingulate motor areas receives ST input. Our meta-analysis of imaging studies indicates that the human equivalents of the three cingulate motor areas also correspond to sites of pain-related activation. The cingulate motor areas in the monkey project directly to the primary motor cortex and to the spinal cord. Thus, the substrate exists for the ST system to have an important influence on the cortical control of movement.
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Hashmi JA, Davis KD. Effect of Static and Dynamic Heat Pain Stimulus Profiles on the Temporal Dynamics and Interdependence of Pain Qualities, Intensity, and Affect. J Neurophysiol 2008; 100:1706-15. [DOI: 10.1152/jn.90500.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute and chronic pains are characterized by a particular constellation of pain qualities, such as burning, aching, stinging, or sharp feelings. However, the temporal pattern of specific pain qualities and their relationship with pain and affect is not well understood. In addition, little is known about how the temperature time course of the stimulus impacts the temporal dynamics of pain qualities and the relationship between pain qualities. Therefore we applied two types of stimuli to the feet of 16 healthy subjects, each calibrated to evoke a similar pain magnitude (50/100): static stimulus held at constant intensity and dynamic stimulus increased in intensity in small steps. Stimulus runs consisted of three 30-s stimuli (either static or dynamic) with an interstimulus interval of 60 s. Continuous on-line ratings of pain, burning, sharp, stinging, cutting, and annoyance were obtained in separate runs, and the evoked responses were characterized by within-stimulus adaptation (early: 0- to 15-s peak vs. late: 25- to 40-s peak) and by their temporal properties (time to onset, peak, and end). The temporal profile of the burning sensation was similar to the pain and annoyance evoked by the static and dynamic stimuli. However, the sharp, stinging and cutting sensations attenuated in response to the static stimuli ( P < 0.01) but intensified along with pain and affect in response to the dynamic stimuli ( P < 0.05), whereas there was no attenuation in the evoked profiles of pain ( P = 0.61), annoyance ( P = 0.27), or burning quality ( P = 0.27). These data demonstrate that specific pain qualities with known differences in underlying mechanisms have distinct temporal dynamics that depend on the stimulus intensity dynamics.
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Ogawa A, Meng ID. The cannabinoid receptor agonist, WIN 55,212-2, inhibits cool-specific lamina I medullary dorsal horn neurons. Neuroscience 2006; 143:265-72. [PMID: 16949215 DOI: 10.1016/j.neuroscience.2006.07.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 07/27/2006] [Accepted: 07/27/2006] [Indexed: 10/24/2022]
Abstract
Cannabinoid receptor agonists have been demonstrated to inhibit medullary and spinal cord dorsal horn nociceptive neurons. The effect of cannabinoids on thermoreceptive specific neurons in the spinal or medullary dorsal horn remains unknown. In the present study, single-unit recordings from the rat medullary dorsal horn were performed to examine the effect of a cannabinoid receptor agonists on cold-specific lamina I spinothalamic tract neurons. The cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (WIN-2), was locally applied to the medullary dorsal horn and the neuronal activity evoked by cooling the receptive field was recorded. WIN-2 (1 microg/microl and 2 microg/microl) significantly attenuated cold-evoked activity. Co-administration of the CB1 receptor antagonist SR 141716 with WIN-2 did not affect cold-evoked activity. These results demonstrate a potential mechanism by which cannabinoids produce hypothermia, and also suggest that cannabinoids may affect non-noxious thermal discrimination.
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Affiliation(s)
- A Ogawa
- Department of Physiology, College of Osteopathic Medicine, University of New England, Biddeford, ME 04005, USA
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Klop EM, Mouton LJ, Holstege G. Segmental and laminar organization of the spinothalamic neurons in cat: evidence for at least five separate clusters. J Comp Neurol 2006; 493:580-95. [PMID: 16304630 DOI: 10.1002/cne.20777] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The spinothalamic tract (STT), well known for its role in the relay of information about noxe, temperature, and crude touch, is usually associated with projections from lamina I, but spinothalamic neurons in other laminae have also been reported. In cat, no complete overview exists of the precise location and number of spinal cells that project to the thalamus. In the present study the laminar distribution of retrogradely labeled cells in all spinal segments (C1-Coc2) was investigated after large WGA-HRP injections in the thalamus. The results show that this distribution of STT cells differed greatly between the different spinal segments. Quantitative analysis showed that there exist at least five separate clusters of spinothalamic neurons. Lamina I neurons in cluster A and lamina V neurons in cluster B are mainly found contralaterally throughout the length of the spinal cord. Cluster C neurons are located bilaterally in the ventrolateral part of laminae VI-VII and lamina VIII of the C1-C3 spinal cord. Cluster D neurons were found contralaterally in lamina VI in the C1-C2 segments, and cluster E neurons were located mainly contralaterally in the medial part of laminae VI-VII and lamina VIII of the lumbosacral cord. Most spinothalamic neurons are not located in the enlargements and most spinothalamic neurons are not located in lamina I, as suggested by several other authors. The location of the spinothalamic neurons shows remarkable similarities, but also differences, with the location of spino-periaqueductal gray neurons.
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Affiliation(s)
- Esther Marije Klop
- Department of Anatomy and Embryology, University Medical Center Groningen, University of Groningen, 9700 AD Groningen, The Netherlands
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Yu XH, Ribeiro-da-Silva A, Ribeiro Da Silva A, De Koninck Y. Morphology and neurokinin 1 receptor expression of spinothalamic lamina I neurons in the rat spinal cord. J Comp Neurol 2006; 491:56-68. [PMID: 16127696 DOI: 10.1002/cne.20675] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Distinct morphological types of spinothalamic tract (STT) lamina I (LI) neurons have been identified in the cat and monkey spinal dorsal horn. Because these morphological types appear to differ in functional properties and receptor expression, we examined their distribution in the rat to test how their identification relates to earlier classification schemes. LI STT cells were retrogradely labeled with cholera toxin subunit b (CTb). Three types were recognized on the basis of cell body shape and proximal dendrites in the horizontal plane: fusiform, multipolar, and pyramidal. The relative distribution of these types was: 43, 26, and 28%, respectively, similar to that observed in the cat and monkey. 3D reconstructions were used to view each cell in all three major projection planes: horizontal, parasagittal, and transverse. Most LI STT neurons appeared fusiform in the parasagittal plane even though they belonged to different types based on their appearance in the horizontal plane, except in the most lateral portion of the dorsal horn, where LI curves ventrally. The proportion of STT neurons within LI was quantified by using the optical dissector method. To label all LI neurons, we used an anti-neuron-specific nuclear protein (NeuN) antibody. We found that approximately 9% of LI neurons projected to the thalamus. We also investigated neurokinin 1 receptor (NK-1r) expression in LI STT neurons. As in the monkey, most pyramidal STT neurons did not express NK-1r. These results provide further evidence that distinct morphological types of neurons differ in phenotype but not in their projection pattern.
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Affiliation(s)
- Xiao Hong Yu
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
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Slack SE, Grist J, Mac Q, McMahon SB, Pezet S. TrkB expression and phospho-ERK activation by brain-derived neurotrophic factor in rat spinothalamic tract neurons. J Comp Neurol 2005; 489:59-68. [PMID: 15977164 DOI: 10.1002/cne.20606] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a neurotrophin implicated in the phenomena of synaptic plasticity in the adult. It is found in terminals of nociceptive primary afferents. Following a pain-related stimulus, it is released in the spinal cord, where it activates its high-affinity receptor TrkB, leading to the phosphorylation of the mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase (ERK). A large body of evidence suggests that BDNF has a positive neuromodulatory effect on glutamate transmission in the spinal cord. However, none of these studies examined anatomically whether projection neurons known to be involved in transmission of nociceptive inputs express BDNF's receptor. Because the spinothalamic tract (STT) is a well-characterized pathway for its role in the transfer and integration of sensory and nociceptive informations, this study in rats aimed to 1) determine whether neurons of the STT pathway express the TrkB receptor, 2) establish the rostrocaudal and laminar distribution of STT-TrkB neurons in the whole spinal cord, and 3) test the potential functionality of TrkB expression in these cells by investigating the ability of BDNF to activate the MAP kinase ERK. Using tract tracing coupled to immunofluorescent labeling for TrkB, we observed that in all levels of the spinal cord most STT neurons were immunoreactive for TrkB. Furthermore, microinjections of BDNF into the spinal cord or release of endogenous BDNF by intraplantar injection of capsaicin activated ERK phosphorylation in TrkB-containing STT neurons. These data suggest an important role for BDNF in nociception as an activator of spinothalamic projection neurons.
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Affiliation(s)
- Sarah E Slack
- The London Pain Consortium, King's College London, Neurorestoration, Center for Age Related Diseases, London SE1 1UL, United Kingdom
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Wilson LB, LeDoux JF, Barnes SR. Brief stimulation of the peroneal nerve attenuates the exercise pressor reflex in anaesthetised cats. Auton Neurosci 2005; 118:1-11. [PMID: 15795173 DOI: 10.1016/j.autneu.2004.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 11/29/2004] [Accepted: 11/30/2004] [Indexed: 11/25/2022]
Abstract
We recently demonstrated that applying capsaicin to the common peroneal nerve, thereby activating small diameter afferent neurons, caused a substantial rise in mean arterial pressure (MAP) and heart rate (HR) that lasted approximately 20 min. In addition, this application of capsaicin transiently attenuated the exercise pressor reflex (EPR). The purpose of the current study was to test the hypothesis that stimulating the peroneal nerve at an intensity that activated both myelinated and unmyelinated axons for a short duration (1 min) causes a similar attenuation of the EPR. Cats were anaesthetised with alpha-chloralose and urethane, the popliteal fossa was exposed, and static contraction was induced by stimulating the tibial nerve. The ipsilateral peroneal nerve was cut and placed on a stimulating electrode. Prior to peroneal nerve stimulation, static contraction of the triceps surae muscle for 1 min increased MAP 48+/-8 mmHg and HR 16+/-3 bpm. Electrical stimulation of the central end of the cut peroneal nerve for 1 min (100 x motor threshold; 40 Hz; 0.1 ms) increased MAP and HR by 62+/-11 mmHg and 28+/-4 bpm, respectively. These increases returned to prestimulation levels within 1 min. Two minutes after the peroneal stimulation was stopped, the EPR was markedly reduced as muscle contraction increased MAP and HR by 20+/-4 mmHg and 7+/-2 bpm, respectively. Repeating the muscle contraction approximately 25 min after peroneal stimulation increased MAP and HR by 38+/-8 mmHg and 12+/-2 bpm, indicating some recovery of the EPR. These results show that brief (1 min) electrical stimulation of afferent neurons in the peroneal nerve attenuates the EPR. This supports the hypothesis that strong activation of small diameter afferent neurons stimulates a nervous system mechanism that diminishes the sensory input from skeletal muscle involved in cardiovascular regulation.
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Affiliation(s)
- L B Wilson
- Department of Pharmacology, Physiology, and Neuroscience, USC School of Medicine, Basic Science Bldg 1, VA Campus, 6439 Garner's Ferry Road, Columbia, SC 29209, USA.
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Klop EM, Mouton LJ, Hulsebosch R, Boers J, Holstege G. In cat four times as many lamina I neurons project to the parabrachial nuclei and twice as many to the periaqueductal gray as to the thalamus. Neuroscience 2005; 134:189-97. [PMID: 15953685 DOI: 10.1016/j.neuroscience.2005.03.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Accepted: 03/16/2005] [Indexed: 11/23/2022]
Abstract
The spinothalamic tract, and especially its fibers originating in lamina I, is the best known pathway for transmission of nociceptive information. On the other hand, different studies have suggested that more lamina I cells project to the parabrachial nuclei (PBN) and periaqueductal gray (PAG) than to the thalamus. The exact ratio of the number of lamina I projections to PBN, PAG and thalamus is not known, because comprehensive studies examining these three projections from all spinal segments, using the same tracers and counting methods, do not exist. In the present study, the differences in number and distribution of retrogradely labeled lamina I cells in each segment of the cat spinal cord (C1-Coc2) were determined after large wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) injections in either PBN, PAG or thalamus. We estimate that approximately 6000 lamina I cells project to PBN, 3000 to PAG and less than 1500 to the thalamus. Of the lamina I cells projecting to thalamus or PAG more than 80%, and of the lamina I-PBN cells approximately 60%, were located on the contralateral side. In all cases, most labeled lamina I cells were found in the upper two cervical segments and in the cervical and lumbar enlargements.
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Affiliation(s)
- E M Klop
- Department of Anatomy and Embryology, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, Building 3215, P.O. Box 196, 9700 AD Groningen, The Netherlands
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Cohen AD, Vander T, Medvendovsky E, Biton A, Naimer S, Shalev R, Vardy DA. Neuropathic scrotal pruritus. J Am Acad Dermatol 2005; 52:61-6. [PMID: 15627082 DOI: 10.1016/j.jaad.2004.04.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Anogenital pruritus is defined as an itch localized to the anus, perianal, and genital skin. Anogenital pruritus is usually a symptom of an underlying disorder of the skin or mucosa or a consequence of anorectal pathology. When no demonstrable cause is found, anogenital pruritus is often described as "idiopathic". OBJECTIVE To investigate the role of lumbosacral radiculopathy in the pathogenesis of anogenital pruritus. METHODS Included in the study were consecutive patients with anogenital pruritus. Radiographs and nerved conduction studies were performed in all patients. Needle electromyography studies and computerized tomography were performed when necessary. Nerve conduction studies included measurement of distal sensory and motor latency, conduction velocity, and F-responses of the peroneal and tibial nerves. Patients with confirmed radiculopathy were treated with paravertebral injection of a mixture of triamcinolne acetonide and lidocaine. Response to the injections was assessed using visual analogue scales by the patients. Mean scores before and after treatment were compared using paired t tests. RESULTS Included in the study were 20 patients with anogenital pruritus. There were 18 men (90%) and 2 (10%) women. The mean age was 52.7 years (standard deviation [SD] 11.7 years). In 16 patients (80%), radiographs demonstrated degenerative changes of the lower spine. In 16 patients (80%) the presence of lumbosacral radiculopathy was confirmed by nerve conduction studies. Fifteen patients (75%) were treated with paravertebral injections, with significant decrease in mean pruritus score as assessed by the patients (6.3 [+/-2.8]; 4.5 [+/-2.7], before and after treatment, respectively, P = .033). CONCLUSION "Idiopathic" anogenital pruritus may be attributable to lumbosacral radiculopathy. Paravertebral blockade may be used for alleviation of symptoms in patients with anogenital pruritus.
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Affiliation(s)
- Arnon D Cohen
- Dermatology Service, Clalit Health Services, Southern District, Israel
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18
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Nomoto S, Shibata M, Iriki M, Riedel W. Role of afferent pathways of heat and cold in body temperature regulation. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2004; 49:67-85. [PMID: 15549421 DOI: 10.1007/s00484-004-0220-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2003] [Revised: 05/22/2004] [Accepted: 05/22/2004] [Indexed: 05/24/2023]
Abstract
The detection of surface and internal temperatures is achieved by axons terminating at lamina I of the spinal dorsal horn, otherwise approached only by nociceptive afferents. Recent advances in thermal physiology research have disclosed that temperature-sensitive ion channels belonging to the "transient receptor potential" family exist in the peripheral sensory neurons and in the brain. Thermosensory, nociceptive and polymodal afferents project to different thalamic nuclei, and specific pathways to the insular cortex evoke the conscious experience of thermal sensation. The posterior insular region represents discriminative thermal sensation, while the largest correlation with subjective ratings of temperature is located in the orbitofrontal and anterior insular cortex. The insular cortex forms an integrative part of the limbic system and is closely tied with the hypothalamus, the amygdala, the anterior cingulate cortex and the orbitofrontal cortex and emerges as the main coordinator of behavioral, autonomic and endocrine responses to both non-noxious and noxious thermal stimuli. The firing rate of warm and cold receptors is not altered by pyrogens. A strong correlation between the onset of fever and production of superoxide by macrophages following the injection of pyrogens implicates reactive oxygen species as elicitors of fever, a hypothesis strengthened by the observation that oxygen radical scavengers or thiol reductants act as antipyretics. Oxidative stress appears to be sensed by the brain and a likely structure for its detection may be the redox-sensitive site of the N-methyl-D-aspartate (NMDA) receptor for glutamate, in that oxidation of this site causes fever while its reduction lowers body temperature, effects which are abrogated by specific NMDA receptor blockers.
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Affiliation(s)
- Shigeki Nomoto
- Tokyo Metropolitan Institute of Gerontology, 173-0015 Tokyo, Japan.
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Urch EC, Donovan-Rodriguez T, Dickenson HA. Alterations in dorsal horn neurones in a rat model of cancer-induced bone pain. Pain 2004; 106:347-356. [PMID: 14659517 DOI: 10.1016/j.pain.2003.08.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cancer-induced bone pain is a major clinical problem. A rat model based on intra-tibial injection of MRMT-1 mammary tumour cells was used to mimic progressive cancer-induced bone pain. At the time of stable behavioural changes (decreased thresholds to mechanical and cold stimuli) and bone destruction, in vivo electrophysiology was used to characterize natural (mechanical, thermal, and cold) and electrical-evoked responses of superficial and deep dorsal horn neurones in halothane-anaesthetized rats. Receptive field size was significantly enlarged for superficial neurones in the MRMT-1 animals. Superficial cells were characterised as either nociceptive specific (NS) or wide dynamic range (WDR). The ratio of WDR to NS cells was substantially different between sham operated (growth media alone) (26:74%) and MRMT-1 injected rats (47:53%). NS cells showed no significant difference in their neuronal responses in MRMT-1-injected compared to sham rats. However, superficial WDR neurones in MRMT-1-injected rats had significantly increased responses to mechanical, thermal and electrical (A beta-, C fibre-, and post-discharge evoked response) stimuli. Deep WDR neurones showed less pronounced changes to the superficial dorsal horn, however, the response to thermal and electrical stimuli, but not mechanical, were significantly increased in the MRMT-1-injected rats. In conclusion, the spinal cord is significantly hyperexcitable with previously superficial NS cells becoming responsive to wide-dynamic range stimuli possibly driving this plasticity via ascending and descending facilitatory pathways. The alterations in superficial dorsal horn neurones have not been reported in neuropathy or inflammation adding to the evidence for cancer-induced bone pain reflecting a unique pain state.
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Affiliation(s)
- E C Urch
- Department of Pharmacology, University College London, Gower St., London WC1E 6BT, UK
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Spike RC, Puskár Z, Andrew D, Todd AJ. A quantitative and morphological study of projection neurons in lamina I of the rat lumbar spinal cord. Eur J Neurosci 2003; 18:2433-48. [PMID: 14622144 DOI: 10.1046/j.1460-9568.2003.02981.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the rat lumbar spinal cord the major supraspinal targets for lamina I projection neurons are the caudal ventrolateral medulla (CVLM), lateral parabrachial area (LPb) and periaqueductal grey matter (PAG). In this study we have estimated the number of lamina I neurons retrogradely labelled from each of these sites in the L4 segment, as well as the proportion that can be labelled by injecting different tracers into two separate sites. Our results suggest that this segment contains approximately 400 lamina I projection neurons on each side, and that approximately 85% of these can be labelled from either the CVLM or the LPb on the contralateral side. Around 120 lamina I cells in L4 project to the PAG, and over 90% of these cells can also be labelled from the CVLM or LPb. Most lamina I neurons projecting to CVLM or LPb are located in the contralateral dorsal horn, but in each case some cells were found to have bilateral projections. We also examined horizontal sections to investigate morphology and the expression of the neurokinin 1 (NK1) receptor in cells labelled from CVLM, LPb or PAG. There were no consistent morphological differences between these groups, however, while cells with strong or moderate NK1 receptor-immunostaining were labelled from LPb or CVLM, they seldom projected to the PAG. These results suggest that many lamina I cells project to more than one site in the brain and that those projecting to PAG may represent a distinct subclass of lamina I projection neuron.
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Affiliation(s)
- R C Spike
- Spinal Cord Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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