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Schwenger N, Dux M, de Col R, Carr R, Messlinger K. Interaction of Calcitonin Gene-Related Peptide, Nitric Oxide and Histamine Release in Neurogenic Blood Flow and Afferent Activation in The Rat Cranial Dura Mater. Cephalalgia 2016; 27:481-91. [PMID: 17441973 DOI: 10.1111/j.1468-2982.2007.01321.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calcitonin gene-related peptide (CGRP), nitric oxide (NO) and histamine are implicated in primary headaches but their role in vascular and nociceptive events in the dura mater is not well described. In an in vitro preparation of the hemisected rat skull, CGRP and histamine release from the cranial dura was measured using enzyme-linked immunoassays. While the NO donator NONOate (10-4 M) was without effect, CGRP (10-5 M) induced considerable histamine release from the rat cranial dura, which was blocked by the CGRP receptor antagonist CGRP8-37 (10-5 M). Conversely, histamine (10-4 M) did not stimulate CGRP release. In vitro recordings from single rat meningeal afferents showed that only one of 12 mechanically identified units but several mechanically insensitive units responded to histamine (up to 10-5 M). Increases in meningeal blood flow after histamine application (10-4 M) to the rat cranial dura remained unchanged during CGRP receptor blockade with CGRP8-37, inhibition of NO synthesis with L-NAME (20 mg/kg i.v.) and H3 receptor blockade with thioperamide (10-4 M). We conclude that histamine produces direct vasodilatation and activates a subset of largely non-mechanically sensitive, non-CGRP containing afferents in the rat meninges. Histamine is released from meningeal mast cells which are stimulated by CGRP. Similar mechanisms may be involved in the pathogenesis of headaches.
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Affiliation(s)
- N Schwenger
- Institute of Physiology & Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany
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Abstract
Central nervous system nuclei and circuits, such as the medial preoptic, ventromedial and paraventricular nuclei of the hypothalamus, play important roles in reproduction and parturition, and are influenced by estrogen. Peripheral autonomic and sensory neurons also play important roles in pregnancy and parturition. Moreover, the steroid hormone estrogen acts directly, not only on the reproductive tract organs (uterus and cervix), but also on the central and peripheral nerves by regulating expression of various neuronal genes. The peripheral primary afferent neurons innervating the uterine cervix relay mechanical and biochemical sensory information induced by local cervical events and by passage of fetuses, to the spinal cord and supraspinal centers. Consequently, the birth process in mammals is influenced by the combined action of neurons and hormones. Peripheral sensory stimuli, induced physiologically by fetal expulsion or mechanically by vaginocervical stimulation, alter behavior, as well as autonomic and neuroendocrine systems. Recent evidence indicates that primary afferent neurons innervating the cervix, in addition to their sensory effects, likely exert local “efferent” actions on the ripening cervix near term. These efferent effects may involve estrogen-regulated production of such neuropeptides as substance P and calcitonin gene-related peptide in lumbosacral dorsal root ganglia, and their release in the cervix. Collectively, these findings suggest an interrelationship among estrogen, cervix-related sensory neurons, and local cervical events near term.
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Affiliation(s)
- C N Mowa
- Northeastern Ohio Universities College of Medicine, Department of Neurobiology, 4209 State Rt. 44, P.O. Box 95, Rootstown, OH 44272, USA
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Coban A, Baslo MB, Baykan B, Tutkavul K, Orhan EK, Ertas M. Subclinical Neuromuscular Transmission Abnormality Detected by Single-Fibre EMG is More Pronounced in Cluster Headache Than in Migraine With Aura. Cephalalgia 2016; 27:788-92. [PMID: 17598760 DOI: 10.1111/j.1468-2982.2007.01341.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The aim was to investigate neuromuscular transmission (NMT) by single-fibre EMG (SFEMG) in a large series of patients having migraine with aura (MA) or cluster headache (CH). Recent studies using SFEMG have shown subclinical dysfunction of NMT in MA and CH. Forty-three patients having MA, 51 with CH and 38 healthy control subjects underwent nerve conduction studies, EMG and SFEMG during voluntary contraction of the extensor digitorum communis muscle. Twenty different potential pairs were recorded and individual, mean and total abnormal individual jitter values were calculated. The results obtained from MA patients were compared with those from CH patients. In MA patients, 32 of 860 jitters were abnormally high, whereas 73 of 1020 of the jitters showed this abnormality in CH patients. None of the control subjects, five MA patients (11.6%) and 11 CH patients (21.6%) were designated as having subclinical NMT abnormality. Thus, patients having junction dysfunction were significantly more common in the CH group. The subclinical NMT abnormality shown by SFEMG is more common in CH than in MA. These two primary headache syndromes may have some shared functional abnormality of NMT constituents which is more evident in CH.
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Affiliation(s)
- A Coban
- Department of Neurology, Clinical Neurophysiology and Headache Subunits, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
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104
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Abstract
To investigate the characteristics of motor, sensory and sensory-evoked potentials (SEPs) of thoracic and lumbar roots, and demonstrate the feasibility of assessing axonal regrowth after the neurotization procedure in a sheep model. Six adult sheep were anaesthetized and placed in a sternal position. The thoracic and lumbar roots from T11 to L5 were identified at their emergence from the vertebral foramen and stimulated. Motor and sensory responses were monitored. Thoracic and lumbar roots were easily identified in all cases. Motor potentials were detected for each stimulated nerve without difficulty. The amplitudes were quite variable, ranging from 100 to 5300 μV. Sensory and SEPs were satisfactorily recorded in only three of the six animals. Sensory amplitudes also varied greatly, ranging from 25 to 120 μV. In three cases, SEPs could not be identified due to motor artefacts. The motor pathway after axonal regrowth in neurotized lumbar roots might easily be explored by proximal electric stimulation of the root, close to the sutured area. Detection of sensory and spinal cord evoked potentials might be improved by the use of curve summation techniques. Specific axonal tracing holds promise of being a useful technique for examining sensory and motor pathway recovery after neurotization in the sheep model.
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Affiliation(s)
- Raphaël Vialle
- Ecole de Chirurgie de l'Assistance Publique des Hôpitaux de Paris, 8-10 rue des Fossés Saint-Marcel, F-75005 Paris, France.
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105
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Saez I, Friedlander MJ. Role of GABAA-Mediated Inhibition and Functional Assortment of Synapses onto Individual Layer 4 Neurons in Regulating Plasticity Expression in Visual Cortex. PLoS One 2016; 11:e0147642. [PMID: 26841221 PMCID: PMC4739708 DOI: 10.1371/journal.pone.0147642] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 01/05/2016] [Indexed: 11/18/2022] Open
Abstract
Layer 4 (L4) of primary visual cortex (V1) is the main recipient of thalamocortical fibers from the dorsal lateral geniculate nucleus (LGNd). Thus, it is considered the main entry point of visual information into the neocortex and the first anatomical opportunity for intracortical visual processing before information leaves L4 and reaches supra- and infragranular cortical layers. The strength of monosynaptic connections from individual L4 excitatory cells onto adjacent L4 cells (unitary connections) is highly malleable, demonstrating that the initial stage of intracortical synaptic transmission of thalamocortical information can be altered by previous activity. However, the inhibitory network within L4 of V1 may act as an internal gate for induction of excitatory synaptic plasticity, thus providing either high fidelity throughput to supragranular layers or transmittal of a modified signal subject to recent activity-dependent plasticity. To evaluate this possibility, we compared the induction of synaptic plasticity using classical extracellular stimulation protocols that recruit a combination of excitatory and inhibitory synapses with stimulation of a single excitatory neuron onto a L4 cell. In order to induce plasticity, we paired pre- and postsynaptic activity (with the onset of postsynaptic spiking leading the presynaptic activation by 10ms) using extracellular stimulation (ECS) in acute slices of primary visual cortex and comparing the outcomes with our previously published results in which an identical protocol was used to induce synaptic plasticity between individual pre- and postsynaptic L4 excitatory neurons. Our results indicate that pairing of ECS with spiking in a L4 neuron fails to induce plasticity in L4-L4 connections if synaptic inhibition is intact. However, application of a similar pairing protocol under GABAARs inhibition by bath application of 2μM bicuculline does induce robust synaptic plasticity, long term potentiation (LTP) or long term depression (LTD), similar to our results with pairing of pre- and postsynaptic activation between individual excitatory L4 neurons in which inhibitory connections are not activated. These results are consistent with the well-established observation that inhibition limits the capacity for induction of plasticity at excitatory synapses and that pre- and postsynaptic activation at a fixed time interval can result in a variable range of plasticity outcomes. However, in the current study by virtue of having two sets of experimental data, we have provided a new insight into these processes. By randomly mixing the assorting of individual L4 neurons according to the frequency distribution of the experimentally determined plasticity outcome distribution based on the calculated convergence of multiple individual L4 neurons onto a single postsynaptic L4 neuron, we were able to compare then actual ECS plasticity outcomes to those predicted by randomly mixing individual pairs of neurons. Interestingly, the observed plasticity profiles with ECS cannot account for the random assortment of plasticity behaviors of synaptic connections between individual cell pairs. These results suggest that connections impinging onto a single postsynaptic cell may be grouped according to plasticity states.
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Affiliation(s)
- Ignacio Saez
- Virginia Tech Carillion Research Institute, 2 Riverside Circle, Roanoke, Virginia 24016, United States of America
| | - Michael J. Friedlander
- Virginia Tech Carillion Research Institute, 2 Riverside Circle, Roanoke, Virginia 24016, United States of America
- * E-mail:
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106
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Kovács I, Luna C, Quirce S, Mizerska K, Callejo G, Riestra A, Fernández-Sánchez L, Meseguer VM, Cuenca N, Merayo-Lloves J, Acosta MC, Gasull X, Belmonte C, Gallar J. Abnormal activity of corneal cold thermoreceptors underlies the unpleasant sensations in dry eye disease. Pain 2016; 157:399-417. [PMID: 26675826 PMCID: PMC4733818 DOI: 10.1097/j.pain.0000000000000455] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/09/2015] [Accepted: 10/28/2015] [Indexed: 12/23/2022]
Abstract
Dry eye disease (DED) affects >10% of the population worldwide, and it provokes an unpleasant sensation of ocular dryness, whose underlying neural mechanisms remain unknown. Removal of the main lachrymal gland in guinea pigs caused long-term reduction of basal tearing accompanied by changes in the architecture and density of subbasal corneal nerves and epithelial terminals. After 4 weeks, ongoing impulse activity and responses to cooling of corneal cold thermoreceptor endings were enhanced. Menthol (200 μM) first excited and then inactivated this augmented spontaneous and cold-evoked activity. Comparatively, corneal polymodal nociceptors of tear-deficient eyes remained silent and exhibited only a mild sensitization to acidic stimulation, whereas mechanonociceptors were not affected. Dryness-induced changes in peripheral cold thermoreceptor responsiveness developed in parallel with a progressive excitability enhancement of corneal cold trigeminal ganglion neurons, primarily due to an increase of sodium currents and a decrease of potassium currents. In corneal polymodal nociceptor neurons, sodium currents were enhanced whereas potassium currents remain unaltered. In healthy humans, exposure of the eye surface to menthol vapors or to cold air currents evoked unpleasant sensations accompanied by increased blinking frequency that we attributed to cold thermoreceptor stimulation. Notably, stimulation with menthol reduced the ongoing background discomfort of patients with DED, conceivably due to use-dependent inactivation of cold thermoreceptors. Together, these data indicate that cold thermoreceptors contribute importantly to the detection and signaling of ocular surface wetness, and develop under chronic eye dryness conditions an injury-evoked neuropathic firing that seems to underlie the unpleasant sensations experienced by patients with DED.
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Affiliation(s)
- Illés Kovács
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Carolina Luna
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Susana Quirce
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Kamila Mizerska
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Gerard Callejo
- Laboratory of Neurophysiology, Department of Biomedicine, School of Medicine, University of Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Ana Riestra
- Instituto Universitario Fernández-Vega, Universidad de Oviedo and Fundación de Investigación Oftalmológica, Oviedo, Spain
| | - Laura Fernández-Sánchez
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Victor M. Meseguer
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Nicolás Cuenca
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Jesús Merayo-Lloves
- Instituto Universitario Fernández-Vega, Universidad de Oviedo and Fundación de Investigación Oftalmológica, Oviedo, Spain
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Xavier Gasull
- Laboratory of Neurophysiology, Department of Biomedicine, School of Medicine, University of Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
- Instituto Universitario Fernández-Vega, Universidad de Oviedo and Fundación de Investigación Oftalmológica, Oviedo, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
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107
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Caron G, Marqueste T, Decherchi P. Long-Term Effects of Botulinum Toxin Complex Type A Injection on Mechano- and Metabo-Sensitive Afferent Fibers Originating from Gastrocnemius Muscle. PLoS One 2015; 10:e0140439. [PMID: 26485650 PMCID: PMC4617719 DOI: 10.1371/journal.pone.0140439] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 09/25/2015] [Indexed: 01/20/2023] Open
Abstract
The aim of the present study was to investigate long term effects of motor denervation by botulinum toxin complex type A (BoNT/A) from Clostridium Botulinum, on the afferent fibers originating from the gastrocnemius muscle of rats. Animals were divided in 2 experimental groups: 1) untreated animals acting as control and 2) treated animals in which the toxin was injected in the left muscle, the latter being itself divided into 3 subgroups according to their locomotor recovery with the help of a test based on footprint measurements of walking rats: i) no recovery (B0), ii) 50% recovery (B50) and iii) full recovery (B100). Then, muscle properties, metabosensitive afferent fiber responses to potassium chloride (KCl) and lactic acid injections and Electrically-Induced Fatigue (EIF), and mechanosensitive responses to tendon vibrations were measured. At the end of the experiment, rats were killed and the toxin injected muscles were weighted. After toxin injection, we observed a complete paralysis associated to a loss of force to muscle stimulation and a significant muscle atrophy, and a return to baseline when the animals recover. The response to fatigue was only decreased in the B0 group. The responses to KCl injections were only altered in the B100 groups while responses to lactic acid were altered in the 3 injected groups. Finally, our results indicated that neurotoxin altered the biphasic pattern of response of the mechanosensitive fiber to tendon vibrations in the B0 and B50 groups. These results indicated that neurotoxin injection induces muscle afferent activity alterations that persist and even worsen when the muscle has recovered his motor activity.
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Affiliation(s)
- Guillaume Caron
- Aix-Marseille Université (AMU) and Centre National de la Recherche Scientifique (CNRS), UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY (ISM-EJM), Equipe, Plasticité des Systèmes Nerveux et Musculaire, Parc Scientifique et Technologique de Luminy, Faculté des Sciences du Sport de Marseille, CC910 - 163 Avenue de Luminy, F-13288, Marseille, cedex 09, France
| | - Tanguy Marqueste
- Aix-Marseille Université (AMU) and Centre National de la Recherche Scientifique (CNRS), UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY (ISM-EJM), Equipe, Plasticité des Systèmes Nerveux et Musculaire, Parc Scientifique et Technologique de Luminy, Faculté des Sciences du Sport de Marseille, CC910 - 163 Avenue de Luminy, F-13288, Marseille, cedex 09, France
| | - Patrick Decherchi
- Aix-Marseille Université (AMU) and Centre National de la Recherche Scientifique (CNRS), UMR 7287, Institut des Sciences du Mouvement: Etienne-Jules MAREY (ISM-EJM), Equipe, Plasticité des Systèmes Nerveux et Musculaire, Parc Scientifique et Technologique de Luminy, Faculté des Sciences du Sport de Marseille, CC910 - 163 Avenue de Luminy, F-13288, Marseille, cedex 09, France
- * E-mail:
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108
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Logan S, Tobin KE, Fallon SC, Deng KS, McDonough AB, Bavis RW. Chronic intermittent hyperoxia alters the development of the hypoxic ventilatory response in neonatal rats. Respir Physiol Neurobiol 2015; 220:69-80. [PMID: 26444750 DOI: 10.1016/j.resp.2015.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/18/2015] [Accepted: 09/28/2015] [Indexed: 11/18/2022]
Abstract
Chronic exposure to sustained hyperoxia alters the development of the respiratory control system, but the respiratory effects of chronic intermittent hyperoxia have rarely been investigated. We exposed newborn rats to short, repeated bouts of 30% O2 or 60% O2 (5 bouts h(-1)) for 4-15 days and then assessed their hypoxic ventilatory response (HVR; 10 min at 12% O2) by plethysmography. The HVR tended to be enhanced by intermittent hyperoxia at P4 (early phase of the HVR), but it was significantly reduced at P14-15 (primarily late phase of the HVR) compared to age-matched controls; the HVR recovered when individuals were returned to room air and re-studied as adults. To investigate the role of carotid body function in this plasticity, single-unit carotid chemoafferent activity was recorded in vitro. Intermittent hyperoxia tended to decrease spontaneous action potential frequency under normoxic conditions but, contrary to expectations, hypoxic responses were only reduced at P4 (not at P14) and only in rats exposed to higher O2 levels (i.e., intermittent 60% O2). Rats exposed to intermittent hyperoxia had smaller carotid bodies, and this morphological change may contribute to the blunted HVR. In contrast to rats exposed to intermittent hyperoxia beginning at birth, two weeks of intermittent 60% O2 had no effect on the HVR or carotid body size of rats exposed beginning at P28; therefore, intermittent hyperoxia-induced respiratory plasticity appears to be unique to development. Although both intermittent and sustained hyperoxia alter carotid body development and the HVR of rats, the specific effects and time course of this plasticity differs.
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Affiliation(s)
- Sarah Logan
- Department of Biology, Bates College, Lewiston, ME 04240 USA
| | | | - Sarah C Fallon
- Department of Biology, Bates College, Lewiston, ME 04240 USA
| | - Kevin S Deng
- Department of Biology, Bates College, Lewiston, ME 04240 USA
| | - Amy B McDonough
- Department of Biology, Bates College, Lewiston, ME 04240 USA
| | - Ryan W Bavis
- Department of Biology, Bates College, Lewiston, ME 04240 USA.
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Khamis HA, Redmond SJ, Macefield VG, Birznieks I. Tactile afferents encode grip safety before slip for different frictions. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2014:4123-6. [PMID: 25570899 DOI: 10.1109/embc.2014.6944531] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Adjustments to frictional forces are crucial to maintain a safe grip during precision object handling in both humans and robotic manipulators. The aim of this work was to investigate whether a population of human tactile afferents can provide information about the current tangential/normal force ratio expressed as the percentage of the critical load capacity - the tangential/normal force ratio at which the object would slip. A smooth stimulation surface was tested on the fingertip under three frictional conditions, with a 4 N normal force and a tangential force generated by motion in the ulnar or distal direction at a fixed speed. During stimulation, the responses of 29 afferents (12 SA-I, 2 SA-II, 12 FA-I, 3 FA-II) were recorded. A multiple regression model was trained and tested using cross-validation to estimate the percentage of the critical load capacity in real-time as the tangential force increased. The features for the model were the number of spikes from each afferent in windows of fixed length (50, 100 or 200 ms) around points spanning the range from 50% to 100% of the critical load capacity, in 5% increments. The mean regression estimate error was less than 1% of the critical load capacity with a standard deviation between 5% and 10%. A larger number of afferents is expected to improve the estimate error. This work is important for understanding human dexterous manipulation and inspiring improvements in robotic grippers and prostheses.
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110
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Poon CS, Song G. Type III-IV muscle afferents are not required for steady-state exercise hyperpnea in healthy subjects and patients with COPD or heart failure. Respir Physiol Neurobiol 2015; 216:78-85. [PMID: 25911558 PMCID: PMC4575501 DOI: 10.1016/j.resp.2015.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/13/2015] [Accepted: 04/14/2015] [Indexed: 12/16/2022]
Abstract
Blockade of group III-IV muscle afferents by intrathecal injection of the μ-opioid agonist fentanyl (IF) in humans has been variously reported to depress exercise hyperpnea in some studies but not others. A key unanswered question is whether such an effect is transient or persists in the steady state. Here we show that in healthy subjects undergoing constant-load cycling exercise IF significantly slows the transient exercise ventilatory kinetics but has no discernible effect on the ventilatory response when exercise is sufficiently prolonged. Thus, the ventilatory response to group III-IV muscle afferents input in healthy subjects is not a simple reflex but acts like a high-pass filter with maximum sensitivity during early-phase exercise and is reset in the late phase. In patients with chronic heart failure (CHF) IF causes sustained CO2 retention not only during exercise but also in the resting state, where muscle afferents feedback is minimal. In patients with chronic obstructive pulmonary disease (COPD), IF also elicits sustained decreases in the exercise ventilatory response but with little or no resultant CO2 retention due to concomitant decreases in physiological VD/VT (dead space-to-ventilation ratio). These results support the proposition that optimal long-term regulation of exercise hyperpnea in health and in disease is determined centrally by the respiratory controller through the continuing adaptation of an internal model which dynamically tracks the metabolic CO2 load and the ventilatory inefficiency 1/1-VD/VT that must be overcome for the maintenance of arterial PCO2 homeostasis, rather than being reflexively driven by group III-IV muscle afferents feedback per se.
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Affiliation(s)
- Chi-Sang Poon
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Bldg E25-250, 77 Massachusetts Avenue, Cambridge, MA, United States.
| | - Gang Song
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Bldg E25-250, 77 Massachusetts Avenue, Cambridge, MA, United States
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Zhang Y, Zhao S, Rodriguez E, Takatoh J, Han BX, Zhou X, Wang F. Identifying local and descending inputs for primary sensory neurons. J Clin Invest 2015; 125:3782-94. [PMID: 26426077 DOI: 10.1172/jci81156] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 07/23/2015] [Indexed: 12/25/2022] Open
Abstract
Primary pain and touch sensory neurons not only detect internal and external sensory stimuli, but also receive inputs from other neurons. However, the neuronal derived inputs for primary neurons have not been systematically identified. Using a monosynaptic rabies viruses-based transneuronal tracing method combined with sensory-specific Cre-drivers, we found that sensory neurons receive intraganglion, intraspinal, and supraspinal inputs, the latter of which are mainly derived from the rostroventral medulla (RVM). The viral-traced central neurons were largely inhibitory but also consisted of some glutamatergic neurons in the spinal cord and serotonergic neurons in the RVM. The majority of RVM-derived descending inputs were dual GABAergic and enkephalinergic (opioidergic). These inputs projected through the dorsolateral funiculus and primarily innervated layers I, II, and V of the dorsal horn, where pain-sensory afferents terminate. Silencing or activation of the dual GABA/enkephalinergic RVM neurons in adult animals substantially increased or decreased behavioral sensitivity, respectively, to heat and mechanical stimuli. These results are consistent with the fact that both GABA and enkephalin can exert presynaptic inhibition of the sensory afferents. Taken together, this work provides a systematic view of and a set of tools for examining peri- and extrasynaptic regulations of pain-afferent transmission.
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112
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Henderson SE, Tudares MA, Gold MS, Almarza AJ. Analysis of pain in the rabbit temporomandibular joint after unilateral splint placement. J Oral Facial Pain Headache 2015; 29:193-202. [PMID: 25905538 DOI: 10.11607/ofph.1371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS To determine whether behavioral, anatomical, and physiologic endpoints widely used to infer the presence of pain in rodent models of temporomandibular disorders (TMD) were applicable to the rabbit model of TMD associated with altered joint loading. METHODS Unilateral molar dental splints were used to alter temporomandibular joint (TMJ) loading. Changes in nociceptive threshold were assessed with a mechanical probing of the TMJ region on nine splinted and three control rabbits. Fos-like immunoreacitivty in the trigeminal subnucleus caudalis was assessed with standard immunohistochemical techniques from three splinted and six control animals. Retrogradely labeled TMJ afferents were studied with patch-clamp electrophysiologic techniques from three splinted and three control animals. Remodeling of TMJ condyles was assessed by histologic investigations of three splinted and three control animals. A Student t test or a Mann-Whitney U test was used with significance set at P < .05 to compare splinted to control samples. RESULTS While variable, there was an increase in mechanical sensitivity in splinted rabbits relative to controls. The increase in Fos+ cells in splinted rabbits was also significant relative to naïve controls (86 ± 8 vs 64 ± 15 cells/section, P < .05). The rheobase (364 ± 80 pA) and action potential threshold (-31.2 ± 2.0 mV) were higher in TMJ afferents from splinted rabbits compared to controls (99 ± 22 pA and -38.0 ± 2.0 mV, P < .05). There was significant remodeling in the condylar fibrocartilage layers as manifested by a change in glycosaminoglycan distribution and a loss of defined cell layers. CONCLUSION Behavioral and anatomical results were consistent with an increase in nociceptive signaling in concert with condylar remodeling driven by altered TMJ loading. Changes in excitability and action potential waveform were consistent with possible compensatory changes of TMJ afferents for an overall increase in afferent drive associated with joint degeneration. These compensatory changes may reflect pain-adaption processes that many patients with TMJ disorders experience.
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113
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Abstract
The physiological and molecular mechanisms of age-related memory loss are complicated by the complexity of vertebrate nervous systems. This study takes advantage of a simple neural model to investigate nervous system aging, focusing on changes in learning and memory in the form of behavioral sensitization in vivo and synaptic facilitation in vitro. The effect of aging on the tail withdrawal reflex (TWR) was studied in Aplysia californica at maturity and late in the annual lifecycle. We found that short-term sensitization in TWR was absent in aged Aplysia. This implied that the neuronal machinery governing nonassociative learning was compromised during aging. Synaptic plasticity in the form of short-term facilitation between tail sensory and motor neurons decreased during aging whether the sensitizing stimulus was tail shock or the heterosynaptic modulator serotonin (5-HT). Together, these results suggest that the cellular mechanisms governing behavioral sensitization are compromised during aging, thereby nearly eliminating sensitization in aged Aplysia.
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Affiliation(s)
- Andrew T. Kempsell
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, Department of Marine Biology and Ecology, Miami, Florida, United States of America
| | - Lynne A. Fieber
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, Department of Marine Biology and Ecology, Miami, Florida, United States of America
- * E-mail:
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114
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Markham CH, Yagi T, Simpson NE. Cat primary canal neurons: relation of conduction velocity to resting and dynamic firing characteristics. Adv Otorhinolaryngol 2015; 25:61-5. [PMID: 484359 DOI: 10.1159/000402918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Spontaneous discharge patterns of first-order canal afferents were analyzed in cats anethetized with pentobarbital sodium with particular emphasis on the relationship of regularity of resting discharge, sensitivity to angular acceleration and adaptation to the time delay between electrical labyrinthine stimulation and recording from afferents near Scarpa's ganglion. Regular units were found to have a high resting rate, low sensitivity to angular acceleration, were mostly nonadapting during prolonged acceleration and showed relatively long latency to electrical stimulation. Irregular units tended to have a low resting rate, high sensitivity, frequently showed adaptation and had short latencies. Intermediate neurons had mixed characteristics of regular and irregular units. In medulated nerve fibers, a direct relation exists between conduction velocity and fiber diameter. As latency is due primarily to conduction in the first-order axon, we may speculate that regular neurons have thin fibers which innervate the slope of the crista, irregular neurons have thick fibers which innervate the summit, and intermediate units have medium caliber fibers which innervate both the slope and summit of the crista ampullaris.
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115
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Abstract
Cases of peripheral labyrinthine lesions were examined by stimulation of the cervical joint and muscle receptors. Head-chin (HC) position to one side induced compensatory oculomotor tone (ipsilateral nystagmus), which depended on the function of the horizontal canal of that side. This compensatory tone increased the duration of the optokinetic after-nystagmus (OKAN), with stripes moving contralaterally to the HC position. Isometric contraction of the muscles which rotate the HC to one side induced ipsilateral oculomotor tone (contralateral nystagmus), which depended on the function of the utricle acting in the same direction. In one case, the muscle-induced tone increased the frequency of the OKN with the slow phase in the same direction; in another, it prolonged the slow-phase pursuit interval. In the absence of a vestibular component, distortion of the OKN was induced.
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116
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Deecke L, Mergner T, Becker W. Neuronal responses to natural vestibular stimuli in the cat's anterior suprasylvian gyrus. Adv Otorhinolaryngol 2015; 25:74-81. [PMID: 314743 DOI: 10.1159/000402920] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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117
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Pfalz RK. The ventral cochlear nucleus: the significance of the crossed, inhibitory pathways towards the nucleus for directional hearing. Fortschr Hals Nasen Ohrenheilkd 2015; 16:1-94. [PMID: 5349592 DOI: 10.1159/000385362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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118
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119
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Abstract
Whether activation of afferent renal nerves contributes to the regulation of arterial pressure and sodium balance has been long overlooked. In normotensive rats, activating renal mechanosensory nerves decrease efferent renal sympathetic nerve activity (ERSNA) and increase urinary sodium excretion, an inhibitory renorenal reflex. There is an interaction between efferent and afferent renal nerves, whereby increases in ERSNA increase afferent renal nerve activity (ARNA), leading to decreases in ERSNA by activation of the renorenal reflexes to maintain low ERSNA to minimize sodium retention. High-sodium diet enhances the responsiveness of the renal sensory nerves, while low dietary sodium reduces the responsiveness of the renal sensory nerves, thus producing physiologically appropriate responses to maintain sodium balance. Increased renal ANG II reduces the responsiveness of the renal sensory nerves in physiological and pathophysiological conditions, including hypertension, congestive heart failure, and ischemia-induced acute renal failure. Impairment of inhibitory renorenal reflexes in these pathological states would contribute to the hypertension and sodium retention. When the inhibitory renorenal reflexes are suppressed, excitatory reflexes may prevail. Renal denervation reduces arterial pressure in experimental hypertension and in treatment-resistant hypertensive patients. The fall in arterial pressure is associated with a fall in muscle sympathetic nerve activity, suggesting that increased ARNA contributes to increased arterial pressure in these patients. Although removal of both renal sympathetic and afferent renal sensory nerves most likely contributes to the arterial pressure reduction initially, additional mechanisms may be involved in long-term arterial pressure reduction since sympathetic and sensory nerves reinnervate renal tissue in a similar time-dependent fashion following renal denervation.
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Affiliation(s)
- Ulla C Kopp
- Departments of Internal Medicine and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa
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120
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Abstract
This article summarizes anatomical, neurophysiological, pharmacological, and brain imaging studies in humans and animals that have provided insights into the neural circuitry and neurotransmitter mechanisms controlling the lower urinary tract. The functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. The neural control of micturition is organized as a hierarchical system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brain stem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brain stem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily in infants and young children until the age of 3 to 5 years, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults can cause the re-emergence of involuntary micturition, leading to urinary incontinence. Neuroplasticity underlying these developmental and pathological changes in voiding function is discussed.
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Affiliation(s)
- William C. de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, School of Medicine Pittsburgh, Pennsylvania
| | - Derek Griffiths
- Department of Medicine (Geriatrics), University of Pittsburgh, School of Medicine Pittsburgh, Pennsylvania
| | - Naoki Yoshimura
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, School of Medicine Pittsburgh, Pennsylvania
- Department of Urology, University of Pittsburgh, School of Medicine Pittsburgh, Pennsylvania
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121
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Abstract
As we all can easily differentiate the sensations of itch and pain, the most straightforward neurophysiologic concept would consist of two specific pathways that independently encode itch and pain. Indeed, a neuronal pathway for histamine-induced itch in the peripheral and central nervous system has been described in animals and humans, and recently several non-histaminergic pathways for itch have been discovered in rodents that support a dichotomous concept differentiated into a pain and an itch pathway, with both pathways being composed of different "flavors." Numerous markers and mediators have been found that are linked to itch processing pathways. Thus, the delineation of neuronal pathways for itch from pain pathways seemingly proves that all sensory aspects of itch are based on an itch-specific neuronal pathway. However, such a concept is incomplete as itch can also be induced by the activation of the pain pathway in particular when the stimulus is applied in a highly localized spatial pattern. These opposite views reflect the old dispute between specificity and pattern theories of itch. Rather than only being of theoretic interest, this conceptual problem has key implication for the strategy to treat chronic itch as key therapeutic targets would be either itch-specific pathways or unspecific nociceptive pathways.
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Affiliation(s)
- Martin Schmelz
- Faculty of Medicine Mannheim, Department of Anesthesiology and Intensive Care Medicine, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany,
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122
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Atala A. Re: Neurosensory perception of environmental cues modulates sperm motility critical for fertilization. J Urol 2014; 193:368-9. [PMID: 25523708 DOI: 10.1016/j.juro.2014.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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123
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Lu CC, Cao XJ, Wright S, Ma L, Oertel D, Goodrich LV. Mutation of Npr2 leads to blurred tonotopic organization of central auditory circuits in mice. PLoS Genet 2014; 10:e1004823. [PMID: 25473838 PMCID: PMC4256264 DOI: 10.1371/journal.pgen.1004823] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 10/14/2014] [Indexed: 12/02/2022] Open
Abstract
Tonotopy is a fundamental organizational feature of the auditory system. Sounds are encoded by the spatial and temporal patterns of electrical activity in spiral ganglion neurons (SGNs) and are transmitted via tonotopically ordered processes from the cochlea through the eighth nerve to the cochlear nuclei. Upon reaching the brainstem, SGN axons bifurcate in a stereotyped pattern, innervating target neurons in the anteroventral cochlear nucleus (aVCN) with one branch and in the posteroventral and dorsal cochlear nuclei (pVCN and DCN) with the other. Each branch is tonotopically organized, thereby distributing acoustic information systematically along multiple parallel pathways for processing in the brainstem. In mice with a mutation in the receptor guanylyl cyclase Npr2, this spatial organization is disrupted. Peripheral SGN processes appear normal, but central SGN processes fail to bifurcate and are disorganized as they exit the auditory nerve. Within the cochlear nuclei, the tonotopic organization of the SGN terminal arbors is blurred and the aVCN is underinnervated with a reduced convergence of SGN inputs onto target neurons. The tonotopy of circuitry within the cochlear nuclei is also degraded, as revealed by changes in the topographic mapping of tuberculoventral cell projections from DCN to VCN. Nonetheless, Npr2 mutant SGN axons are able to transmit acoustic information with normal sensitivity and timing, as revealed by auditory brainstem responses and electrophysiological recordings from VCN neurons. Although most features of signal transmission are normal, intermittent failures were observed in responses to trains of shocks, likely due to a failure in action potential conduction at branch points in Npr2 mutant afferent fibers. Our results show that Npr2 is necessary for the precise spatial organization typical of central auditory circuits, but that signals are still transmitted with normal timing, and that mutant mice can hear even with these deficits.
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Affiliation(s)
- Cindy C. Lu
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xiao-Jie Cao
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Samantha Wright
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Le Ma
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Donata Oertel
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Lisa V. Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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124
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Ross JL, Queme LF, Shank AT, Hudgins RC, Jankowski MP. Sensitization of group III and IV muscle afferents in the mouse after ischemia and reperfusion injury. J Pain 2014; 15:1257-70. [PMID: 25245401 PMCID: PMC4302035 DOI: 10.1016/j.jpain.2014.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/22/2014] [Accepted: 09/04/2014] [Indexed: 12/12/2022]
Abstract
UNLABELLED Ischemic myalgia is a unique type of muscle pain in the patient population. The role that discrete muscle afferent subpopulations play in the generation of pain during ischemic events, however, has yet to be determined. Using 2 brachial artery occlusion models to compare prolonged ischemia or transient ischemia with reperfusion of the muscles, we found that both injuries caused behavioral decrements in grip strength, as well as increased spontaneous pain behaviors. Using our ex vivo forepaw muscles, median and ulnar nerves, dorsal root ganglion, and spinal cord recording preparation, we found after both prolonged and transient ischemia that there was a significant increase in the number of afferents that responded to both noxious and non-noxious chemical (lactate, adenosine triphosphate, varying pH) stimulation of the muscles compared to uninjured controls. However, we found an increase in firing to heat stimuli specifically in muscle afferents during prolonged ischemia, but a distinct increase in afferent firing to non-noxious chemicals and decreased mechanical thresholds after transient ischemia. The unique changes in afferent function observed also corresponded with distinct patterns of gene expression in the dorsal root ganglia. Thus, the development of ischemic myalgia may be generated by unique afferent-based mechanisms during prolonged and transient ischemia. PERSPECTIVE This study analyzed the response properties of thinly myelinated group III and unmyelinated group IV muscle afferents during prolonged and transient ischemia in addition to pain behaviors and alterations in DRG gene expression in the mouse. Results suggest that mechanisms of pain generation during prolonged ischemia may be different from ischemia/reperfusion.
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Affiliation(s)
- Jessica L. Ross
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Luis F. Queme
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Aaron T. Shank
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Renita C. Hudgins
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Michael P. Jankowski
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
- Department of Pediatrics, University of Cincinnati, Cincinnati OH 45229
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125
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Devor M, Vaso A, Adahan HM, Vyshka G. PNS origin of phantom limb sensation and pain: reply to letter to the editor regarding Foell et al., peripheral origin of phantom limb pain: is it all resolved? Pain 2014; 155:2207-2208. [PMID: 25168666 DOI: 10.1016/j.pain.2014.08.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 02/08/2023]
Affiliation(s)
- Marshall Devor
- Department of Cell & Developmental Biology, Institute of Life Sciences and Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem, Israel Pain and Rehabilitation Clinic, National Trauma Center, Trauma University Hospital and Galenus Clinic, Tirana, Albania Pain Rehabilitation Unit, Chaim Sheba Medical Center, Tel Hashomer, Israel Biomedical and Experimental Department, Faculty of Medicine, University of Medicine, Tirana, Albania
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126
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Carter AW, Chen SC, Lovell NH, Vickery RM, Morley JW. Convergence across tactile afferent types in primary and secondary somatosensory cortices. PLoS One 2014; 9:e107617. [PMID: 25215534 PMCID: PMC4162646 DOI: 10.1371/journal.pone.0107617] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 08/21/2014] [Indexed: 11/29/2022] Open
Abstract
Integration of information by convergence of inputs onto sensory cortical neurons is a requisite for processing higher-order stimulus features. Convergence across defined peripheral input classes has generally been thought to occur at levels beyond the primary sensory cortex, however recent work has shown that this does not hold for the convergence of slowly-adapting and rapidly-adapting inputs in primary somatosensory cortex. We have used a new analysis method for multi-unit recordings, to show convergence of inputs deriving from the rapidly-adapting and Pacinian channels in a proportion of neurons in both primary and secondary somatosensory cortex in the anaesthetised cat. We have validated this method using single-unit recordings. The secondary somatosensory cortex has a greater proportion of sites that show convergence of this type than primary somatosensory cortex. These findings support the hypothesis that the more complex features processed in higher cortical areas require a greater degree of convergence across input classes, but also shows that this convergence is apparent in the primary somatosensory cortex.
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Affiliation(s)
| | - Spencer C. Chen
- School of Medical Sciences, UNSW Australia, Sydney, Australia
- Graduate School of Biomedical Engineering, UNSW Australia, Sydney, Australia
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Nigel H. Lovell
- Graduate School of Biomedical Engineering, UNSW Australia, Sydney, Australia
| | | | - John W. Morley
- School of Medical Sciences, UNSW Australia, Sydney, Australia
- School of Medicine, University of Western Sydney, Penrith, Australia
- * E-mail:
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127
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Olsen ACK, Triblehorn JD. Neural responses from the filiform receptor neuron afferents of the wind-sensitive cercal system in three cockroach species. J Insect Physiol 2014; 68:76-86. [PMID: 25046275 PMCID: PMC4451162 DOI: 10.1016/j.jinsphys.2014.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/09/2014] [Accepted: 07/11/2014] [Indexed: 06/03/2023]
Abstract
The wind-sensitive insect cercal system is involved in many important behaviors, such as initiating terrestrial escape responses and providing sensory feedback during flight. The occurrence of these behaviors vary in cockroach species Periplaneta americana (strong terrestrial response and flight), Blaberus craniifer (weak terrestrial response and flight), and Gromphodorhina portentosa (no terrestrial response and no flight). A previous study focusing on wind-sensitive interneuron (WSI) responses demonstrated that variations in sensory processing of wind information accompany these behavioral differences. In this study, we recorded extracellularly from the cercal nerve to characterize filiform afferent population responses to different wind velocities to investigate how sensory processing differs across these species at the initial encoding of wind. We compared these results and responses from the WSI population to examine information transfer at the first synapse. Our main results were: (1) G. portentosa had the weakest responses of the three species over the stimulus duration and possessed the smallest cerci with the least filiform hair receptors of the three species; (2) B. craniifer filiform responses were similar to or greater than P. americana responses even though B. craniifer possessed smaller cerci with less filiform hair receptors than P. americana; (3) the greater filiform afferent responses in B. craniifer, including a larger amplitude second positive peak compared to the other two species, suggest more synchronous activity between filiform afferents in this species; (4) the transfer of information at the first synapse appears to be similar in both P. americana and G. portentosa, but different in B. craniifer.
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Affiliation(s)
- Anne C K Olsen
- Department of Biology and Program in Neuroscience, College of Charleston, 66 George Street, Charleston, SC 29424, USA
| | - Jeffrey D Triblehorn
- Department of Biology and Program in Neuroscience, College of Charleston, 66 George Street, Charleston, SC 29424, USA.
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128
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Abstract
During neural development, neurons extend axons to target areas of the brain. Through processes of growth, branching and retraction these axons establish stereotypic patterns of connectivity. In the visual system, these patterns include retinotopic organization and the segregation of individual axons onto different subsets of target neurons based on the eye of origin (ocular dominance) or receptive field type (ON or OFF). Characteristic disruptions to these patterns occur when neural activity or guidance molecule expression is perturbed. In this paper we present a model that explains how these developmental patterns might emerge as a result of the coordinated growth and retraction of individual axons and synapses responding to position-specific markers, trophic factors and spontaneous neural activity. This model derives from one presented earlier (Godfrey et al., 2009) but which is here extended to account for a wider range of phenomena than previously described. These include ocular dominance and ON-OFF segregation and the results of altered ephrinA and EphA guidance molecule expression. The model takes into account molecular guidance factors, realistic patterns of spontaneous retinal wave activity, trophic molecules, homeostatic mechanisms, axon branching and retraction rules and intra-axonal signaling mechanisms that contribute to the survival of nearby synapses on an axon. We show that, collectively, these mechanisms can account for a wider range of phenomena than previous models of retino-tectal development.
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Affiliation(s)
- Keith B. Godfrey
- NERF, Leuven, Belgium
- imec, Leuven, Belgium
- Canadian Centre for Behavioral Neuroscience, University of Lethbridge, Alberta, Canada
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada
- * E-mail:
| | - Nicholas V. Swindale
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada
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129
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Abstract
In this paper, we present a digital signal processor (DSP) capable of monitoring the urinary bladder volume through afferent neural pathways. The DSP carries out real-time detection and can discriminate extracellular action potentials, also known as on-the-fly spike sorting. Next, the DSP performs a decoding method to estimate either three qualitative levels of fullness or the bladder volume value, depending on the selected output mode. The proposed DSP was tested using both realistic synthetic signals with a known ground-truth, and real signals from bladder afferent nerves recorded during acute experiments with animal models. The spike sorting processing circuit yielded an average accuracy of 92% using signals with highly correlated spike waveforms and low signal-to-noise ratios. The volume estimation circuits, tested with real signals, reproduced accuracies achieved by offline simulations in Matlab, i.e., 94% and 97% for quantitative and qualitative estimations, respectively. To assess feasibility, the DSP was deployed in the Actel FPGA Igloo AGL1000V2, which showed a power consumption of 0.5 mW and a latency of 2.1 ms at a 333 kHz core frequency. These performance results demonstrate that an implantable bladder sensor that perform the detection, discrimination and decoding of afferent neural activity is feasible.
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130
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Rahman M, Okamoto K, Thompson R, Bereiter DA. Trigeminal pathways for hypertonic saline- and light-evoked corneal reflexes. Neuroscience 2014; 277:716-23. [PMID: 25086311 DOI: 10.1016/j.neuroscience.2014.07.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/03/2014] [Accepted: 07/04/2014] [Indexed: 11/18/2022]
Abstract
Cornea-evoked eyeblinks maintain tear film integrity on the ocular surface in response to dryness and protect the eye from real or potential damage. Eyelid movement following electrical stimulation has been well studied in humans and animals; however, the central neural pathways that mediate protective eyeblinks following natural nociceptive signals are less certain. The aim of this study was to assess the role of the trigeminal subnucleus interpolaris/caudalis (Vi/Vc) transition and subnucleus caudalis/upper cervical cord (Vc/C1) junction regions on orbicularis oculi electromyographic (OOemg) activity evoked by ocular surface application of hypertonic saline or exposure to bright light in urethane anesthetized male rats. The Vi/Vc and Vc/C1 regions are the main sites of termination for trigeminal afferent nerves that supply the ocular surface, while hypertonic saline (saline=0.15-5M) and bright light (light=5k-20klux) selectively activate ocular surface and intraocular trigeminal nerves, respectively, and excite second-order neurons at the Vi/Vc and Vc/C1 regions. Integrated OOemg activity, ipsilateral to the applied stimulus, increased with greater stimulus intensities for both modalities. Lidocaine applied to the ocular surface inhibited OOemg responses to hypertonic saline, but did not alter the response to light. Lidocaine injected into the trigeminal ganglion blocked completely the OOemg responses to hypertonic saline and light indicating a trigeminal afferent origin. Synaptic blockade by cobalt chloride of the Vi/Vc or Vc/C1 region greatly reduced OOemg responses to hypertonic saline and bright light. These data indicate that OOemg activity evoked by natural stimuli known to cause irritation or discomfort in humans depends on a relay in both the Vi/Vc transition and Vc/C1 junction regions.
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Affiliation(s)
- M Rahman
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Moos Tower 18-186, 515 Delaware Street SE, Minneapolis, MN 55455, USA.
| | - K Okamoto
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Moos Tower 18-186, 515 Delaware Street SE, Minneapolis, MN 55455, USA
| | - R Thompson
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Moos Tower 18-186, 515 Delaware Street SE, Minneapolis, MN 55455, USA
| | - D A Bereiter
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Moos Tower 18-186, 515 Delaware Street SE, Minneapolis, MN 55455, USA
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131
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Woolf CJ. What to call the amplification of nociceptive signals in the central nervous system that contribute to widespread pain? Pain 2014; 155:1911-1912. [PMID: 25083929 DOI: 10.1016/j.pain.2014.07.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 07/24/2014] [Indexed: 11/19/2022]
Affiliation(s)
- Clifford J Woolf
- FM Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
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132
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Schmidt ERE, Brignani S, Adolfs Y, Lemstra S, Demmers J, Vidaki M, Donahoo ALS, Lilleväli K, Vasar E, Richards LJ, Karagogeos D, Kolk SM, Pasterkamp RJ. Subdomain-mediated axon-axon signaling and chemoattraction cooperate to regulate afferent innervation of the lateral habenula. Neuron 2014; 83:372-387. [PMID: 25033181 DOI: 10.1016/j.neuron.2014.05.036] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2014] [Indexed: 11/20/2022]
Abstract
A dominant feature of neural circuitry is the organization of neuronal projections and synapses into specific brain nuclei or laminae. Lamina-specific connectivity is controlled by the selective expression of extracellular guidance and adhesion molecules in the target field. However, how (sub)nucleus-specific connections are established and whether axon-derived cues contribute to subdomain targeting are largely unknown. Here, we demonstrate that the lateral subnucleus of the habenula (lHb) determines its own afferent innervation by sending out efferent projections that express the cell adhesion molecule LAMP to reciprocally collect and guide dopaminergic afferents to the lHb-a phenomenon we term subdomain-mediated axon-axon signaling. This process of reciprocal axon-axon interactions cooperates with lHb-specific chemoattraction mediated by Netrin-1, which controls axon target entry, to ensure specific innervation of the lHb. We propose that cooperation between pretarget reciprocal axon-axon signaling and subdomain-restricted instructive cues provides a highly precise and general mechanism to establish subdomain-specific neural circuitry.
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Affiliation(s)
- Ewoud Roberto Eduard Schmidt
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Sara Brignani
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Youri Adolfs
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Suzanne Lemstra
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Jeroen Demmers
- Proteomics Centre and Department of Cell Biology, Erasmus University Medical Centre, Dr Molewaterplein 50, 3015 GE Rotterdam, the Netherlands
| | - Marina Vidaki
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology, Vassilika Vouton, Heraklion GR-7110, Greece
| | - Amber-Lee Skye Donahoo
- Queensland Brain Institute and The School of Biomedical Sciences, University of Queensland, Building 79, St Lucia Campus, Brisbane, QLD 4067, Australia
| | - Kersti Lilleväli
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Eero Vasar
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Linda Jane Richards
- Queensland Brain Institute and The School of Biomedical Sciences, University of Queensland, Building 79, St Lucia Campus, Brisbane, QLD 4067, Australia
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology, Vassilika Vouton, Heraklion GR-7110, Greece
| | - Sharon Margriet Kolk
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Ronald Jeroen Pasterkamp
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands.
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133
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Vaso A, Adahan HM, Gjika A, Zahaj S, Zhurda T, Vyshka G, Devor M. Peripheral nervous system origin of phantom limb pain. Pain 2014; 155:1384-1391. [PMID: 24769187 DOI: 10.1016/j.pain.2014.04.018] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 04/06/2014] [Accepted: 04/14/2014] [Indexed: 02/08/2023]
Abstract
Nearly all amputees continue to feel their missing limb as if it still existed, and many experience chronic phantom limb pain (PLP). What is the origin of these sensations? There is currently a broad consensus among investigators that PLP is a top-down phenomenon, triggered by loss of sensory input and caused by maladaptive cortical plasticity. We tested the alternative hypothesis that PLP is primarily a bottom-up process, due not to the loss of input but rather to exaggerated input, generated ectopically in axotomized primary afferent neurons in the dorsal root ganglia (DRGs) that used to innervate the limb. In 31 amputees, the local anesthetic lidocaine was applied intrathecally and/or to the DRG surface (intraforaminal epidural block). This rapidly and reversibly extinguished PLP and also nonpainful phantom limb sensation (npPLS). Control injections were ineffective. For intraforaminal block, the effect was topographically appropriate. The suppression of PLP and npPLS could also be demonstrated using dilute lidocaine concentrations that are sufficient to suppress DRG ectopia but not to block the propagation of impulses generated further distally in the nerve. PLP is driven primarily by activity generated within the DRG. We recommend the DRG as a target for treatment of PLP and perhaps also other types of regional neuropathic pain.
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Affiliation(s)
- Apostol Vaso
- Pain and Rehabilitation Clinic, National Trauma Center, Trauma University Hospital and Galenus Clinic, Tirana, Albania Pain Rehabilitation Unit, Chaim Sheba Medical Center, Tel Hashomer 52621, Israel Biomedical and Experimental Department, Faculty of Medicine, University of Medicine, Tirana, Albania Department of Cell and Developmental Biology, Institute of Life Sciences and Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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134
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Ringkamp M, Raja SN. A sore spot: central or peripheral generation of chronic neuropathic spontaneous pain? Pain 2014; 155:1189-1191. [PMID: 24928202 DOI: 10.1016/j.pain.2014.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 04/01/2014] [Indexed: 10/25/2022]
Affiliation(s)
- Matthias Ringkamp
- Department of Neurosurgery, Johns Hopkins University, School of Medicine, 600 N Wolfe St., Meyer 5-109, Baltimore, MD 21287, USA Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21287, USA
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135
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Zhao J, Levy D. The sensory innervation of the calvarial periosteum is nociceptive and contributes to headache-like behavior. Pain 2014; 155:1392-1400. [PMID: 24769138 PMCID: PMC4058402 DOI: 10.1016/j.pain.2014.04.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 04/09/2014] [Accepted: 04/14/2014] [Indexed: 10/25/2022]
Abstract
Headaches are thought to result from the activation and sensitization of nociceptors that innervate deep cephalic tissues. A large body of evidence supports the view that some types of headaches originate intracranially, from activation of sensory neurons that innervate the cranial meninges. However, the notion of an extracranial origin of headaches continues to be entertained, although the identity of deep extracranial cephalic tissues that might contribute to headaches remains elusive. Here we employed anatomical, electrophysiological, and behavioral approaches in rats to test the hypothesis that the sensory innervation of the calvarial periosteum is nociceptive. Neural tracing indicated that the calvarial periosteum overlying the frontal and parietal bones is innervated primarily by small and medium-sized neurons in the trigeminal ganglion's ophthalmic division. In vivo single-unit recording in the trigeminal ganglion revealed that calvarial periosteal afferents have slowly conducting axons, are mechanosensitive, and respond to inflammatory mediators, consistent with a nociceptive function. Two distinct neuronal populations were distinguished based on their peripheral axonal trajectory: one that reached the periosteum through extracranial branches of the trigeminal nerve, and another that took an intracranial trajectory, innervating the cranial dura and apparently reaching the periosteum via the calvarial sutures. In behavioral studies, inflammatory stimulation of these afferents promoted periorbital tactile hypersensitivity, a sensory change linked to primary headaches. Activation and sensitization of calvarial periosteal afferents could play a role in mediating primary headaches of extracranial and perhaps also intracranial origin, as well as secondary headaches such as postcraniotomy and posttraumatic headaches. Targeting calvarial periosteal afferents may be effective in ameliorating these headaches.
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Affiliation(s)
- Jun Zhao
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
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136
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137
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Mulders WHAM, Barry KM, Robertson D. Effects of furosemide on cochlear neural activity, central hyperactivity and behavioural tinnitus after cochlear trauma in guinea pig. PLoS One 2014; 9:e97948. [PMID: 24835470 PMCID: PMC4023991 DOI: 10.1371/journal.pone.0097948] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/27/2014] [Indexed: 11/19/2022] Open
Abstract
Cochlear trauma causes increased spontaneous activity (hyperactivity) to develop in central auditory structures, and this has been suggested as a neural substrate for tinnitus. Using a guinea pig model we have previously demonstrated that for some time after cochlear trauma, central hyperactivity is dependent on peripheral afferent drive and only later becomes generated intrinsically within central structures. Furosemide, a loop diuretic, reduces spontaneous firing of auditory afferents. We investigated in our guinea pig model the efficacy of furosemide in reducing 1) spontaneous firing of auditory afferents, using the spectrum of neural noise (SNN) from round window recording, 2) hyperactivity in inferior colliculus, using extracellular single neuron recordings and 3) tinnitus at early time-points after cochlear trauma. Tinnitus was assessed using gap prepulse inhibition of acoustic startle (GPIAS). Intraperitoneal furosemide, but not saline, caused a marked decrease in both SNN and central hyperactivity. Intracochlear perfusion with furosemide similarly reversed central hyperactivity. In animals in which GPIAS measurements suggested the presence of tinnitus (reduced GPIAS), this could be reversed with an intraperitoneal injection with furosemide but not saline. The results are consistent with furosemide reducing central hyperactivity and behavioural signs of tinnitus by acting peripherally to decrease spontaneous firing of auditory afferents. The data support the notion that hyperactivity may be involved in the generation of tinnitus and further suggest that there may be a therapeutic window after cochlear trauma using drug treatments that target peripheral spontaneous activity.
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Affiliation(s)
- Wilhelmina H. A. M. Mulders
- The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
- * E-mail:
| | - Kristin M. Barry
- The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Donald Robertson
- The Auditory Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
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138
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Nobrega ACL, O'Leary D, Silva BM, Marongiu E, Piepoli MF, Crisafulli A. Neural regulation of cardiovascular response to exercise: role of central command and peripheral afferents. Biomed Res Int 2014; 2014:478965. [PMID: 24818143 PMCID: PMC4000959 DOI: 10.1155/2014/478965] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/04/2014] [Indexed: 12/12/2022]
Abstract
During dynamic exercise, mechanisms controlling the cardiovascular apparatus operate to provide adequate oxygen to fulfill metabolic demand of exercising muscles and to guarantee metabolic end-products washout. Moreover, arterial blood pressure is regulated to maintain adequate perfusion of the vital organs without excessive pressure variations. The autonomic nervous system adjustments are characterized by a parasympathetic withdrawal and a sympathetic activation. In this review, we briefly summarize neural reflexes operating during dynamic exercise. The main focus of the present review will be on the central command, the arterial baroreflex and chemoreflex, and the exercise pressure reflex. The regulation and integration of these reflexes operating during dynamic exercise and their possible role in the pathophysiology of some cardiovascular diseases are also discussed.
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Affiliation(s)
- Antonio C. L. Nobrega
- Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, RJ, Brazil
| | - Donal O'Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Bruno Moreira Silva
- Section of Exercise Physiology, Department of Physiology, Federal University of São Paulo, SP, Brazil
| | - Elisabetta Marongiu
- Sports Physiology laboratory Lab., Department of Medical Sciences, University of Cagliari, Italy
| | - Massimo F. Piepoli
- Heart Failure Unit, Cardiac Department, Guglielmo da Saliceto Polichirurgico Hospital, Piacenza, Italy
| | - Antonio Crisafulli
- Sports Physiology laboratory Lab., Department of Medical Sciences, University of Cagliari, Italy
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139
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Gerling GJ, Rivest II, Lesniak DR, Scanlon JR, Wan L. Validating a population model of tactile mechanotransduction of slowly adapting type I afferents at levels of skin mechanics, single-unit response and psychophysics. IEEE Trans Haptics 2014; 7:216-228. [PMID: 24960553 PMCID: PMC4300237 DOI: 10.1109/toh.2013.36] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Previous models of touch have linked skin mechanics to neural firing rate, neural dynamics to action potential elicitation, and mechanoreceptor populations to psychophysical discrimination. However, no one model spans all levels. The objective of work herein is to build a multi-level, computational model of tactile neurons embedded in cutaneous skin, and then validate its predictions of skin surface deflection, single-afferent firing to indenter shift, and population response for sphere discrimination. The model includes a 3D finite element representation of the distal phalange with hyper- and visco-elastic mechanics. Distributed over its surface, a population of receptor models is comprised of bi-phasic functions to represent Merkel cells' transformation of stress/strain to membrane current and a leaky integrate-and-fire neuronal models to generate the timing of action potentials. After including neuronal noise, the predictions of two population encoding strategies (gradient sum and euclidean distance) are compared to psychophysical discrimination of spheres. Results indicate that predicted skin surface deflection matches Srinivasan's observations for 50 micron and 3.17 mm diameter cylinders and single-afferent responses achieve R(2) = 0.81 when compared to Johnson's recordings. Discrimination results correlate with Goodwin's experiments, whereby 287 and 365 m(-1) spheres are more discriminable than 287 and 296 m(-1).
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Mendus D, Sundaresan S, Grillet N, Wangsawihardja F, Leu R, Müller U, Jones SM, Mustapha M. Thrombospondins 1 and 2 are important for afferent synapse formation and function in the inner ear. Eur J Neurosci 2014; 39:1256-67. [PMID: 24460873 PMCID: PMC4132060 DOI: 10.1111/ejn.12486] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 12/05/2013] [Accepted: 12/18/2013] [Indexed: 12/12/2022]
Abstract
Thrombospondins (TSPs) constitute a family of secreted extracellular matrix proteins that have been shown to be involved in the formation of synapses in the central nervous system. In this study, we show that TSP1 and TSP2 are expressed in the cochlea, and offer the first description of their putative roles in afferent synapse development and function in the inner ear. We examined mice with deletions of TSP1, TSP2 and both (TSP1/TSP2) for inner ear development and function. Immunostaining for synaptic markers indicated a significant decrease in the number of formed afferent synapses in the cochleae of TSP2 and TSP1/TSP2 knockout (KO) mice at postnatal day (P)29. In functional studies, TSP2 and TSP1/TSP2 KO mice showed elevated auditory brainstem response (ABR) thresholds as compared with wild-type littermates, starting at P15, with the most severe phenotype being seen for TSP1/TSP2 KO mice. TSP1/TSP2 KO mice also showed reduced wave I amplitudes of ABRs and vestibular evoked potentials, suggesting synaptic dysfunction in both the auditory and vestibular systems. Whereas ABR thresholds in TSP1 KO mice were relatively unaffected at early ages, TSP1/TSP2 KO mice showed the most severe phenotype among all of the genotypes tested, suggesting functional redundancy between the two genes. On the basis of the above results, we propose that TSPs play an important role in afferent synapse development and function of the inner ear.
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Affiliation(s)
- Diana Mendus
- Department of Otolaryngology – Head and Neck Surgery, Stanford University, Stanford, CA, USA, 94305
| | - Srividya Sundaresan
- Department of Otolaryngology – Head and Neck Surgery, Stanford University, Stanford, CA, USA, 94305
| | - Nicolas Grillet
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA, USA, 92037
| | - Felix Wangsawihardja
- Department of Otolaryngology – Head and Neck Surgery, Stanford University, Stanford, CA, USA, 94305
| | - Rose Leu
- Department of Otolaryngology – Head and Neck Surgery, Stanford University, Stanford, CA, USA, 94305
| | - Ulrich Müller
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA, USA, 92037
| | - Sherri M. Jones
- Department of Special Education & Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE, USA, 68583
| | - Mirna Mustapha
- Department of Otolaryngology – Head and Neck Surgery, Stanford University, Stanford, CA, USA, 94305
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141
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Battisti AC, Fantetti KN, Moyers BA, Fekete DM. A subset of chicken statoacoustic ganglion neurites are repelled by Slit1 and Slit2. Hear Res 2014; 310:1-12. [PMID: 24456709 PMCID: PMC3979322 DOI: 10.1016/j.heares.2014.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 12/20/2013] [Accepted: 01/09/2014] [Indexed: 01/23/2023]
Abstract
Mechanosensory hair cells in the chicken inner ear are innervated by bipolar afferent neurons of the statoacoustic ganglion (SAG). During development, individual SAG neurons project their peripheral process to only one of eight distinct sensory organs. These neuronal subtypes may respond differently to guidance cues as they explore the periphery in search of their target. Previous gene expression data suggested that Slit repellants might channel SAG neurites into the sensory primordia, based on the presence of robo transcripts in the neurons and the confinement of slit transcripts to the flanks of the prosensory domains. This led to the prediction that excess Slit proteins would impede the outgrowth of SAG neurites. As predicted, axonal projections to the primordium of the anterior crista were reduced 2-3 days after electroporation of either slit1 or slit2 expression plasmids into the anterior pole of the otocyst on embryonic day 3 (E3). The posterior crista afferents, which normally grow through and adjacent to slit expression domains as they are navigating towards the posterior pole of the otocyst, did not show Slit responsiveness when similarly challenged by ectopic delivery of slit to their targets. The sensitivity to ectopic Slits shown by the anterior crista afferents was more the exception than the rule: responsiveness to Slits was not observed when the entire E4 SAG was challenged with Slits for 40 h in vitro. The corona of neurites emanating from SAG explants was unaffected by the presence of purified human Slit1 and Slit2 in the culture medium. Reduced axon outgrowth from E8 olfactory bulbs cultured under similar conditions for 24 h confirmed bioactivity of purified human Slits on chicken neurons. In summary, differential sensitivity to Slit repellents may influence the directional outgrowth of otic axons toward either the anterior or posterior otocyst.
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Affiliation(s)
- Andrea C Battisti
- Department of Biological Sciences and Purdue University Center for Cancer Research, Purdue University, 915 W State St., West Lafayette, IN 47907-1392, USA.
| | - Kristen N Fantetti
- Department of Biological Sciences and Purdue University Center for Cancer Research, Purdue University, 915 W State St., West Lafayette, IN 47907-1392, USA.
| | - Belle A Moyers
- Department of Biological Sciences and Purdue University Center for Cancer Research, Purdue University, 915 W State St., West Lafayette, IN 47907-1392, USA.
| | - Donna M Fekete
- Department of Biological Sciences and Purdue University Center for Cancer Research, Purdue University, 915 W State St., West Lafayette, IN 47907-1392, USA.
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142
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Sengupta JN, Mickle A, Kannampalli P, Spruell R, McRorie J, Shaker R, Miranda A. Visceral analgesic effect of 5-HT(4) receptor agonist in rats involves the rostroventral medulla (RVM). Neuropharmacology 2014; 79:345-58. [PMID: 24334068 PMCID: PMC4321751 DOI: 10.1016/j.neuropharm.2013.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/21/2013] [Accepted: 12/04/2013] [Indexed: 12/31/2022]
Abstract
The 5-HT(4) receptor agonist tegaserod (TEG) has been reported to modulate visceral pain. However, the underlying mechanism remains unknown. The objective of the present study was to examine the analgesic mechanism and site of action of TEG. In male rats, visceral pain was assessed by measuring visceromotor response (VMR) to colorectal distension (CRD). Inflammation was induced by intracolonic injection of tri-nitrobenzene sulfonic acid (TNBS). The effect of TEG on the VMR was tested by injecting intraperitoneal (i.p.), intrathecal (i.t.), intracerebroventricular (i.c.v) or in the rostroventral medulla (RVM). The effect of the drug was also tested on responses of CRD-sensitive pelvic nerve afferents (PNA) and lumbo-sacral (LS) spinal neurons. Systemic injection of TEG attenuated VMR in naive and TNBS-treated rats. Similarly, supraspinal, but not spinal, injection of TEG attenuated the VMR. While GR113808, (selective 5-HT(4) antagonist) blocked the effect, naloxone (NLX) an opioid receptor antagonist reversed the effect of TEG. Although i.t. NLX did not block the inhibitory effect of TEG in VMR study, i.t. injection of α2-adrenergic receptor antagonist yohimbine blocked the effect of TEG when given systemically. While TEG had no effect on the responses of CRD-sensitive PNA, it inhibited the responses of CRD-sensitive LS neurons in spinal intact condition. This inhibition was blocked by GR113808, NLX and β-funaltrexamine (β-FNA) when injected into the RVM. Results indicate that TEG produces analgesia via activation of supraspinal 5-HT(4) receptors which triggers the release of opioids at supraspinal site, which activates descending noradrenergic pathways to the spinal cord to produce analgesia.
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Affiliation(s)
- Jyoti N Sengupta
- Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Aaron Mickle
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Pradeep Kannampalli
- Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - John McRorie
- Procter & Gamble Pharmaceuticals Inc., Mason, OH, USA
| | - Reza Shaker
- Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Adrian Miranda
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
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143
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Abstract
Comparison of the functional organization of sensory modalities can reveal the specialized mechanisms unique to each modality as well as processing algorithms that are common across modalities. Here we examine the rodent whisker system. The whisker's mechanical properties shape the forces transmitted to specialized receptors. The sensory and motor systems are intimately interconnected, giving rise to two forms of sensation: generative and receptive. The sensory pathway is a test bed for fundamental concepts in computation and coding: hierarchical feature detection, sparseness, adaptive representations, and population coding. The central processing of signals can be considered a sequence of filters. At the level of cortex, neurons represent object features by a coordinated population code which encompasses cells with heterogeneous properties.
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Affiliation(s)
- Miguel Maravall
- Instituto de Neurociencias de Alicante UMH-CSIC, Campus de San Juan, Apartado 18, 03550 Sant Joan d'Alacant, Spain
| | - Mathew E Diamond
- Tactile Perception and Learning Lab, International School for Advanced Studies-SISSA, Via Bonomea 265, 34136 Trieste, Italy.
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144
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Bruns TM, Weber DJ, Gaunt RA. Microstimulation of afferents in the sacral dorsal root ganglia can evoke reflex bladder activity. Neurourol Urodyn 2014; 34:65-71. [PMID: 24464833 DOI: 10.1002/nau.22514] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/19/2013] [Indexed: 11/07/2022]
Abstract
AIMS Pudendal afferent fibers can be excited using electrical stimulation to evoke reflex bladder activity. While this approach shows promise for restoring bladder function, stimulation of desired pathways, and integration of afferent signals for sensory feedback remains challenging. At sacral dorsal root ganglia (DRG), the convergence of pelvic and pudendal afferent fibers provides a unique location for access to lower urinary tract neurons. Our goal in this study was to demonstrate the potential of microstimulation in sacral DRG for evoking reflex bladder responses. METHODS Penetrating microelectrode arrays were inserted in the left S1 and S2 DRG of six anesthetized adult male cats. While the bladder volume was held at a level below the leak volume, single and multiple channel stimulation was performed using various stimulation patterns. RESULTS Reflex bladder excitation was observed in five cats, for stimulation in either S1 or S2 DRG at 1 Hz and 30-33 Hz with a pulse amplitude of 10-50 µA. Bladder relaxation was observed during a few trials. Adjacent electrodes frequently elicited very different responses. CONCLUSIONS These results demonstrate the potential of low-current microstimulation to recruit reflexive bladder responses. An approach such as this could be integrated with DRG recordings of bladder afferents to provide a closed-loop bladder neuroprosthesis.
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Affiliation(s)
- Tim M Bruns
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennysylvania
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145
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Taylor BK, Fu W, Kuphal KE, Stiller CO, Winter MK, Chen W, Corder GF, Urban JH, McCarson KE, Marvizon JC. Inflammation enhances Y1 receptor signaling, neuropeptide Y-mediated inhibition of hyperalgesia, and substance P release from primary afferent neurons. Neuroscience 2013; 256:178-94. [PMID: 24184981 DOI: 10.1016/j.neuroscience.2013.10.054] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 10/21/2013] [Accepted: 10/23/2013] [Indexed: 12/20/2022]
Abstract
Neuropeptide Y (NPY) is present in the superficial laminae of the dorsal horn and inhibits spinal nociceptive processing, but the mechanisms underlying its anti-hyperalgesic actions are unclear. We hypothesized that NPY acts at neuropeptide Y1 receptors in the dorsal horn to decrease nociception by inhibiting substance P (SP) release, and that these effects are enhanced by inflammation. To evaluate SP release, we used microdialysis and neurokinin 1 receptor (NK1R) internalization in rat. NPY decreased capsaicin-evoked SP-like immunoreactivity in the microdialysate of the dorsal horn. NPY also decreased non-noxious stimulus (paw brush)-evoked NK1R internalization (as well as mechanical hyperalgesia and mechanical and cold allodynia) after intraplantar injection of carrageenan. Similarly, in rat spinal cord slices with dorsal root attached, [Leu(31), Pro(34)]-NPY inhibited dorsal root stimulus-evoked NK1R internalization. In rat dorsal root ganglion neurons, Y1 receptors colocalized extensively with calcitonin gene-related peptide (CGRP). In dorsal horn neurons, Y1 receptors were extensively expressed and this may have masked the detection of terminal co-localization with CGRP or SP. To determine whether the pain inhibitory actions of Y1 receptors are enhanced by inflammation, we administered [Leu(31), Pro(34)]-NPY after intraplantar injection of complete Freund's adjuvant (CFA) in rat. We found that [Leu(31), Pro(34)]-NPY reduced paw clamp-induced NK1R internalization in CFA rats but not uninjured controls. To determine the contribution of increased Y1 receptor-G protein coupling, we measured [(35)S]GTPγS binding simulated by [Leu(31), Pro(34)]-NPY in mouse dorsal horn. CFA inflammation increased the affinity of Y1 receptor G-protein coupling. We conclude that Y1 receptors contribute to the anti-hyperalgesic effects of NPY by mediating the inhibition of SP release, and that Y1 receptor signaling in the dorsal horn is enhanced during inflammatory nociception.
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Affiliation(s)
- B K Taylor
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, KY 40536, USA.
| | - W Fu
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, KY 40536, USA
| | - K E Kuphal
- Division of Pharmacology, University of Missouri-Kansas City, Kansas City, MO, USA
| | - C-O Stiller
- Department of Medicine, Division of Clinical Pharmacology, Karolinska Hospital, Karolinska Institutet, Stockholm, Sweden
| | - M K Winter
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - W Chen
- Veteran Affairs Greater Los Angeles Healthcare System and Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
| | - G F Corder
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, KY 40536, USA
| | - J H Urban
- Department of Physiology and Biophysics, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - K E McCarson
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - J C Marvizon
- Veteran Affairs Greater Los Angeles Healthcare System and Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
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146
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Abstract
While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing interest in the underlying neural mechanisms of itch, which has become a vibrant and rapidly-advancing field of research. The goal of the present forefront review is to describe the recent progress that has been made in our understanding of itch mechanisms.
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Affiliation(s)
- Tasuku Akiyama
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, United States
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147
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Sakurai K, Akiyama M, Cai B, Scott A, Han BX, Takatoh J, Sigrist M, Arber S, Wang F. The organization of submodality-specific touch afferent inputs in the vibrissa column. Cell Rep 2013; 5:87-98. [PMID: 24120861 DOI: 10.1016/j.celrep.2013.08.051] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 08/08/2013] [Accepted: 08/30/2013] [Indexed: 11/19/2022] Open
Abstract
The rodent tactile vibrissae are innervated by several different types of touch sensory neurons. The central afferents of all touch neurons from one vibrissa collectively project to a columnar structure called a barrelette in the brainstem. Delineating how distinct types of sensors connect to second-order neurons within each barrelette is critical for understanding tactile information coding and processing. Using genetic and viral techniques, we labeled slowly adapting (SA) mechanosensory neurons, rapidly adapting (RA) mechanosensory neurons, afferent synapses, and second-order projection neurons with four different fluorescent markers to examine their connectivity. We discovered that within each vibrissa column, individual sensory neurons project collaterals to multiply distributed locations, inputs from SA and RA afferents are spatially intermixed without any discernible stereotypy or topography, and second-order projection neurons receive convergent SA and RA inputs. Our findings reveal a "one-to-many and many-to-one" connectivity scheme and the circuit architecture for tactile information processing at the first-order synapses.
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Affiliation(s)
- Katsuyasu Sakurai
- Department of Cell Biology, Box 3709, Duke University Medical Center, Durham, NC 27710, USA
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148
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Lipski WJ, Grace AA. Footshock-induced responses in ventral subiculum neurons are mediated by locus coeruleus noradrenergic afferents. Eur Neuropsychopharmacol 2013; 23:1320-8. [PMID: 23394871 PMCID: PMC3718869 DOI: 10.1016/j.euroneuro.2012.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/15/2012] [Accepted: 10/18/2012] [Indexed: 12/29/2022]
Abstract
The ventral subiculum (vSub) of the hippocampus is critically involved in mediating the forebrain's response to stress, particularly with regard to psychogenic stressors. Stress, in turn, is known to aggravate many psychiatric conditions including schizophrenia, depression, anxiety, and drug abuse. Pathological alterations in hippocampal function have been identified in all these disorders; thus, it is of interest to understand how stress affects this brain region. The vSub receives dense projections from the stress-related locus coeruleus (LC); however, it is not known what role this input plays in signaling stressful stimuli. In this study, the direct LC innervation of the vSub was investigated as a potential mediator of stress responses in this region. To examine responses to an acute stressor, the effect of footshock on single vSub neurons was tested in rats. Footshock inhibited 13%, and activated 48% of neurons in this region. Importantly, responses to footshock were correlated with LC stimulation-evoked responses in single neurons, and LC inactivation blocked these responses. Furthermore, prazosin, an alpha-1 antagonist, reversed footshock-evoked inhibition, revealing an underlying activation. Inactivation of the basolateral amygdala (BLA) did not block phasic footshock-evoked activation; however, it reduced tonic activity in the vSub. These results suggest that the LC NE system plays an important role in mediating stress responses in the vSub. Footshock evokes both inhibition and excitation in the vSub, by activating noradrenergic inputs from the LC. These responses may contribute to stress adaptation; while an imbalance of this system may lead to pathological stress responses in mental disorders.
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Affiliation(s)
- Witold J Lipski
- Departments of Neuroscience, Psychiatry and Psychology, Center for Neuroscience, A210 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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149
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Warnsinck CJ, Shemesh H, Lobbezoo F. [Persistent pain following endodontic treatment]. Ned Tijdschr Tandheelkd 2013; 120:530-536. [PMID: 25026740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dental pain is a very common pain in the orofacial area. Patients sometimes experience persistent pain following endodontic treatment. The cause of this pain can be found in the endodontically treated tooth itself when the pain persists after an inadequately performed treatment. Persistent pain is also possible after an apparently adequate endodontic treatment. Moreover the pain can have an odontogenic origin, in cases where the diagnostic procedure may have failed. A non-odontogenic cause can be located in proximate or more remote structures, which may be a question of systemic diseases or pain from neuropathic, neurovascular and/or psychogenic conditions. A thorough clinical examination forms the basis for the establishment of a valid diagnosis.
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150
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Abstract
The effects of neonatal food restriction upon the dendritic development of facial nucleus (FN) motor neurons of Wistar rats were analyzed. Rats neonatally underfed by daily (12 h) mother-litter separation in an incubator from 5-30 days after birth exhibited, in brain stem Golgi-Cox sections, significant reductions in the number and extension of stellate, triangular and bipolar FN neuronal dendritic prolongations with negligible effects upon perikarya measurements. Data suggest that in the underfed newborn, the ability of FN neurons to establish synaptic contacts with afferent fibers is reduced, which then interferes with their capacities for the integration and triggering of nerve impulses to modulate facial motor expression in response to sensory cues.
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Affiliation(s)
- C Torrero
- Department of Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus UNAM Juriquilla, Querétaro, Qro., 76001 México
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