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Upadhyay A, Gradwell MA, Vajtay TJ, Conner J, Sanyal AA, Azadegan C, Patel KR, Thackray JK, Bohic M, Imai F, Ogundare SO, Yoshida Y, Abdus-Saboor I, Azim E, Abraira VE. The Dorsal Column Nuclei Scale Mechanical Sensitivity in Naive and Neuropathic Pain States. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.20.581208. [PMID: 38712022 PMCID: PMC11071288 DOI: 10.1101/2024.02.20.581208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Tactile perception relies on reliable transmission and modulation of low-threshold information as it travels from the periphery to the brain. During pathological conditions, tactile stimuli can aberrantly engage nociceptive pathways leading to the perception of touch as pain, known as mechanical allodynia. Two main drivers of peripheral tactile information, low-threshold mechanoreceptors (LTMRs) and postsynaptic dorsal column neurons (PSDCs), terminate in the brainstem dorsal column nuclei (DCN). Activity within the DRG, spinal cord, and DCN have all been implicated in mediating allodynia, yet the DCN remains understudied at the cellular, circuit, and functional levels compared to the other two. Here, we show that the gracile nucleus (Gr) of the DCN mediates tactile sensitivity for low-threshold stimuli and contributes to mechanical allodynia during neuropathic pain in mice. We found that the Gr contains local inhibitory interneurons in addition to thalamus-projecting neurons, which are differentially innervated by primary afferents and spinal inputs. Functional manipulations of these distinct Gr neuronal populations resulted in bidirectional changes to tactile sensitivity, but did not affect noxious mechanical or thermal sensitivity. During neuropathic pain, silencing Gr projection neurons or activating Gr inhibitory neurons was able to reduce tactile hypersensitivity, and enhancing inhibition was able to ameliorate paw withdrawal signatures of neuropathic pain, like shaking. Collectively, these results suggest that the Gr plays a specific role in mediating hypersensitivity to low-threshold, innocuous mechanical stimuli during neuropathic pain, and that Gr activity contributes to affective, pain-associated phenotypes of mechanical allodynia. Therefore, these brainstem circuits work in tandem with traditional spinal circuits underlying allodynia, resulting in enhanced signaling of tactile stimuli in the brain during neuropathic pain.
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Affiliation(s)
- Aman Upadhyay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
- Neuroscience PhD program at Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Mark A Gradwell
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Thomas J Vajtay
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - James Conner
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Arnab A Sanyal
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Chloe Azadegan
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Komal R Patel
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
| | - Joshua K Thackray
- Human Genetics Institute of New Jersey, Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Manon Bohic
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Fumiyasu Imai
- Burke Neurological Institute, White Plains, New York City, New York, USA
- Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA
| | - Simon O Ogundare
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York City, New York, USA
| | - Yutaka Yoshida
- Burke Neurological Institute, White Plains, New York City, New York, USA
- Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA
| | - Ishmail Abdus-Saboor
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Department of Biological Sciences, Columbia University, New York City, New York, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Victoria E Abraira
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA; Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
- Lead contact
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Lee IS, Necka EA, Atlas LY. Distinguishing pain from nociception, salience, and arousal: How autonomic nervous system activity can improve neuroimaging tests of specificity. Neuroimage 2020; 204:116254. [PMID: 31604122 PMCID: PMC6911655 DOI: 10.1016/j.neuroimage.2019.116254] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 12/16/2022] Open
Abstract
Pain is a subjective, multidimensional experience that is distinct from nociception. A large body of work has focused on whether pain processing is supported by specific, dedicated brain circuits. Despite advances in human neuroscience and neuroimaging analysis, dissociating acute pain from other sensations has been challenging since both pain and non-pain stimuli evoke salience and arousal responses throughout the body and in overlapping brain circuits. In this review, we discuss these challenges and propose that brain-body interactions in pain can be leveraged in order to improve tests for pain specificity. We review brain and bodily responses to pain and nociception and extant efforts toward identifying pain-specific brain networks. We propose that autonomic nervous system activity should be used as a surrogate measure of salience and arousal to improve these efforts and enable researchers to parse out pain-specific responses in the brain, and demonstrate the feasibility of this approach using example fMRI data from a thermal pain paradigm. This new approach will improve the accuracy and specificity of functional neuroimaging analyses and help to overcome current difficulties in assessing pain specific responses in the human brain.
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Affiliation(s)
- In-Seon Lee
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Elizabeth A Necka
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Lauren Y Atlas
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA; National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA; National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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Neurophysiological Responses to Different Product Experiences. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2018; 2018:9616301. [PMID: 30344600 PMCID: PMC6174742 DOI: 10.1155/2018/9616301] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/09/2018] [Accepted: 08/07/2018] [Indexed: 11/23/2022]
Abstract
It is well known that the evaluation of a product from the shelf considers the simultaneous cerebral and emotional evaluation of the different qualities of the product such as its colour, the eventual images shown, and the envelope's texture (hereafter all included in the term “product experience”). However, the measurement of cerebral and emotional reactions during the interaction with food products has not been investigated in depth in specialized literature. The aim of this paper was to investigate such reactions by the EEG and the autonomic activities, as elicited by the cross-sensory interaction (sight and touch) across several different products. In addition, we investigated whether (i) the brand (Major Brand or Private Label), (ii) the familiarity (Foreign or Local Brand), and (iii) the hedonic value of products (Comfort Food or Daily Food) influenced the reaction of a group of volunteers during their interaction with the products. Results showed statistically significantly higher tendency of cerebral approach (as indexed by EEG frontal alpha asymmetry) in response to comfort food during the visual exploration and the visual and tactile exploration phases. Furthermore, for the same index, a higher tendency of approach has been found toward foreign food products in comparison with local food products during the visual and tactile exploration phase. Finally, the same comparison performed on a different index (EEG frontal theta) showed higher mental effort during the interaction with foreign products during the visual exploration and the visual and tactile exploration phases. Results from the present study could deepen the knowledge on the neurophysiological response to food products characterized by different nature in terms of hedonic value familiarity; moreover, they could have implications for food marketers and finally lead to further study on how people make food choices through the interactions with their commercial envelope.
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Steadman CJ, Hubscher CH. Sexual Function after Spinal Cord Injury: Innervation, Assessment, and Treatment. CURRENT SEXUAL HEALTH REPORTS 2016. [DOI: 10.1007/s11930-016-0067-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Del Fiacco M, Quartu M, Serra MP, Boi M, Demontis R, Poddighe L, Picci C, Melis T. The human cuneate nucleus contains discrete subregions whose neurochemical features match those of the relay nuclei for nociceptive information. Brain Struct Funct 2013; 219:2083-101. [PMID: 23975345 PMCID: PMC4223579 DOI: 10.1007/s00429-013-0625-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 08/04/2013] [Indexed: 12/21/2022]
Abstract
The present paper is aimed at defining distinctive subdivisions of the human cuneate nucleus (Cu), evident from prenatal to old life, whose occurrence has never been clearly formalized in the human brain, or described in other species so far. It extends our early observations on the presence of gray matter areas that host strong substance P (SP) immunoreactivity in the territory of the human Cu and adjacent cuneate fascicle. Here we provide a three-dimensional reconstruction of the Cu fields rich in SP and further identify those areas by means of their immunoreactivity to the neuropeptides SP, calcitonin gene-related peptide, methionine- and leucine-enkephalin, peptide histidine-isoleucine, somatostatin and galanin, to the trophins glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor, and to the neuroplasticity proteins polysialylated neural cell adhesion molecule and growth-associated protein-43. The presence, density and distribution of immunoreactivity for each of these molecules closely resemble those occurring in the superficial layers of the caudal spinal trigeminal nucleus (Sp5C). Myelin and Nissl stainings suggest that those Cu subregions and the Sp5C superficial layers share a similar histological aspect. This work establishes the existence of definite subregions, localized within the Cu territory, that bear the neurochemical and histological features of sensory nuclei committed to the neurotransmission of protopathic stimuli, including pain. These findings appear of particular interest when considering that functional, preclinical and clinical studies show that the dorsal column nuclei, classical relay station of fine somatic tactile and proprioceptive sensory stimuli, are also involved in pain neurotransmission.
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Affiliation(s)
- Marina Del Fiacco
- Department of Biomedical Sciences, Section of Cytomorphology, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, Italy,
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Saderi N, Cazarez-Márquez F, Buijs FN, Salgado-Delgado RC, Guzman-Ruiz MA, del Carmen Basualdo M, Escobar C, Buijs RM. The NPY intergeniculate leaflet projections to the suprachiasmatic nucleus transmit metabolic conditions. Neuroscience 2013; 246:291-300. [PMID: 23680526 DOI: 10.1016/j.neuroscience.2013.05.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 11/27/2022]
Abstract
The intergeniculate leaflet (IGL) is classically known as the area of the Thalamic Lateral Geniculate Complex providing the suprachiasmatic nucleus (SCN) non-photic information. In the present study we investigated whether this information might be related to the metabolic state of the animal. The following groups of male Wistar rats were used for analysis of neuropeptide Y (NPY) and c-Fos in the IGL and SCN. (1) Fed ad libitum. (2) Fasted for 48 h. (3) Fasted for 48 h followed by refeeding for 3 h. (4) Monosodium glutamate-lesioned and 48 h fasted. (5) Electrolytic lesion in the IGL and 48 h fasted. The results were quantified by optical densitometry. Neuronal tracers were injected in two brain areas that receive metabolic information from the periphery, the arcuate nucleus (ARC) and Nucleus of the Tractus Solitarius to investigate whether there is an anatomical relationship with the IGL. Lesion studies showed the IGL, and not the ARC, as origin of most NPY projections to the SCN. Fasting induced important changes in the NPY expression in the IGL, coinciding with similar changes of NPY/glutamate decarboxylase projections of the IGL to the SCN. These changes revealed that the IGL is involved in the transmission of metabolic information to the SCN. In fasted animals IGL lesion resulted in a significant increase of c-Fos in the SCN as compared to intact fasted animals demonstrating the inhibitory influence of the IGL to the SCN in fasting conditions. When the animal after fasting was refed, an increase of c-Fos in the SCN indicated a removal of this inhibitory input. Together these observations show that in addition to increased inhibitory IGL input during fasting, the negative metabolic condition also results in increased excitatory input to the SCN via other pathways. Consequently the present observations show that at least part of the non-photic input to the SCN, arising from the IGL contains information about metabolic conditions.
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Affiliation(s)
- N Saderi
- Laboratory of Hypothalamic Integration Mechanism, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apartado Postal 70228, Ciudad Universitaria, 04510 Mexico DF, Mexico
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Cruz-Almeida Y, Felix ER, Martinez-Arizala A, Widerström-Noga EG. Decreased spinothalamic and dorsal column medial lemniscus-mediated function is associated with neuropathic pain after spinal cord injury. J Neurotrauma 2012; 29:2706-15. [PMID: 22845918 DOI: 10.1089/neu.2012.2343] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neuropathic pain (NP) after spinal cord injury (SCI) can significantly and negatively affect quality of life and is often refractory to currently available treatments. In order to find more effective therapeutic avenues, it would be helpful to identify the primary underlying pathophysiological mechanisms in each individual. The aim of the present study was to assess the relationship between the presence and severity of NP after SCI and measures of somatosensory function mediated via the dorsal column medial lemniscal (DCML) pathway and the spinothalamic tract (STT). Vibratory, mechanical, thermal, and pain thresholds measured in areas at and below the neurological level of injury (LOI) in persons with SCI and NP (SCI-NP, n=47) and in persons with SCI without NP (SCI-noNP, n=18) were normalized to data obtained from able-bodied pain-free control subjects (A-B, n=30). STT-mediated function at and below the LOI was significantly impaired in both SCI groups compared with A-B controls (p<0.001), but not significantly different between the two SCI groups (NP vs. no-NP). In contrast, the SCI-NP group had significantly greater impairment of DCML-mediated function at the LOI, as reflected by greater vibratory detection deficits (z=-3.89±0.5), compared with the SCI-noNP group (z=-1.95±0.7, p=0.034). Within the SCI-NP group, NP severity was significantly associated with increased thermal sensitivity below the LOI (r=0.50, p=0.038). Our results suggest that both impaired STT and DCML-mediated function are necessary for the development of NP after SCI. However, within the SCI-NP group, greater NP severity was associated with greater sensitivity to thermal stimuli below the LOI. This finding concurs with other studies suggesting that STT damage with some sparing is associated with NP.
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Affiliation(s)
- Yenisel Cruz-Almeida
- Research Service, Department of Veterans Affairs Medical Center, Miami, Florida, USA
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Neural acupuncture unit: a new concept for interpreting effects and mechanisms of acupuncture. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:429412. [PMID: 22474503 PMCID: PMC3310280 DOI: 10.1155/2012/429412] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Revised: 11/30/2011] [Accepted: 12/01/2011] [Indexed: 12/12/2022]
Abstract
When an acupuncture needle is inserted into a designated point on the body and
mechanical or electrical stimulation is delivered, various neural and neuroactive
components are activated. The collection of the activated neural and neuroactive
components distributed in the skin, muscle, and connective tissues surrounding the
inserted needle is defined as a neural acupuncture unit (NAU). The traditionally defined
acupoints represent an anatomical landmark system that indicates local sites where NAUs
may contain relatively dense and concentrated neural and neuroactive components, upon
which acupuncture stimulation would elicit a more efficient therapeutic response. The
NAU-based local mechanisms of biochemical and biophysical reactions play an important
role in acupuncture-induced analgesia. Different properties of NAUs are associated with
different components of needling sensation. There exist several central pathways to
convey NAU-induced acupuncture signals, Electroacupuncture (EA) frequency-specific
neurochemical effects are related to different peripheral and central pathways transmitting
afferent signals from different frequency of NAU stimulation. More widespread and intense
neuroimaging responses of brain regions to acupuncture may be a consequence of more
efficient NAU stimulation modes. The introduction of the conception of NAU provides a
new theoretical approach to interpreting effects and mechanisms of acupuncture in
modern biomedical knowledge framework.
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Upper thoracic postsynaptic dorsal column neurons conduct cardiac mechanoreceptive information, but not cardiac chemical nociception in rats. Brain Res 2010; 1366:71-84. [PMID: 20869348 DOI: 10.1016/j.brainres.2010.09.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 09/15/2010] [Accepted: 09/16/2010] [Indexed: 11/23/2022]
Abstract
Postsynaptic dorsal column (PSDC) neurons transmit noxious visceral information from the lower thoracic and lumbosacral spinal cord. Cuneothalamic neurons in the PSDC pathway and upper thoracic (T(3)-T(4)) spinal neurons ascending through the ventrolateral funiculus (VLF) have been shown to transmit nociceptive cardiac information. Therefore, we hypothesized that upper thoracic PSDC neurons transmit noxious cardiac information. Neuronal responses to intrapericardially injected mechanical (1.0 ml saline) and noxious chemical (0.2 ml algogenic chemicals) stimuli were recorded from antidromically activated PSDC and VLF neurons in the T(3)-T(4) spinal cord of anesthetized Sprague-Dawley rats. Of the PSDC neurons, 43% responded to mechanical stimulation, but only one responded to noxious chemical stimuli. Fifty-eight percent of VLF neurons responded to mechanical stimulation and all responded to noxious chemical stimulation. Fluoro-Ruby (FR)-labeled PSDC neurons in the T(3)-T(4) spinal cord of Sprague-Dawley rats were processed for c-fos immunohistochemistry following intrapericardial stimulation with mechanical, chemical, or control stimuli. Sections were viewed under epifluorescence and light microscopy to detect FR-labeled neurons containing a c-fos immunoreactive (IR) nucleus. An average of 6 PSDC neurons per rat was found in the T(3) and T(4) spinal segments. The average number of c-fos-IR neurons per segment varied by type of stimulus: 12 (control), 67 (chemical) and 85 (mechanical) for T(3) and 8 (control), 37 (chemical) and 62 (mechanical) for T(4). None of the 200 PSDC neurons examined expressed c-fos-IR regardless of stimulus. Together, these results suggest that thoracic PSDC neurons transmit mechanical cardiac information, but they play a minimal role in cardiac nociception.
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Qin C, Goodman MD, Little JM, Farber JP, Foreman RD. Comparison of activity characteristics of the cuneate nucleus and thoracic spinal neurons receiving noxious cardiac and/or somatic inputs in rats. Brain Res 2010; 1346:102-11. [PMID: 20595052 DOI: 10.1016/j.brainres.2010.05.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2010] [Revised: 05/08/2010] [Accepted: 05/25/2010] [Indexed: 11/15/2022]
Abstract
Previous studies have shown that the gracile nucleus in postsynaptic dorsal column pathway plays an important role in conveying nociceptive information from pelvic visceral organs. The purpose of this study was to compare effects of a noxious cardiac stimulus on neuronal activity in the cuneate nucleus and upper thoracic spinal cord in rats. Extracellular potentials of single neurons in the cuneate nucleus and upper thoracic (T3) spinal cord were recorded in pentobarbital anesthetized, ventilated and paralyzed male rats. To activate cardiac nociceptors, a silicone tube was placed in the pericardial sac over the left ventricle to administer a solution of bradykinin (10 microg/ml, 0.2 ml, 1 min). The number of cuneate neurons responding to intrapericardial bradykinin (IB, 15.6%, 17/109) was significantly less than for T3 neurons (43.2%, 48/111, P<0.05). IB excited 9/17 (52.9%) cuneate neurons and inhibited eight neurons. In contrast, IB excited a significantly higher percentage of responding spinal neurons than those in cuneate nucleus (43/48, 89.6%, P<0.01). The ratio of short latency/long-lasting responses of cuneate neurons to IB (14/3) were significant higher than responses of spinal neurons (26/22, P<0.05). Spontaneous activity (5.5+/-0.7 imp/s), response amplitudes (6.0+/-0.6 imp/s) and durations (83.4+/-10.8 sec) of cuneate neurons excited by IB were significantly less than for spinal neurons (11.5+/-1.3 imp/s, 20.4+/-2.0 imp/s and 104.9+/-7.0 imp/s, P<0.01, P<0.01, P<0.05), respectively. These results indicate that the cuneate nucleus neurons play a relatively minor role in transmission of cardiac nociceptive information in comparison to upper thoracic spinal neurons.
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Affiliation(s)
- Chao Qin
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.
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Spinal cord injuries containing asymmetrical damage in the ventrolateral funiculus is associated with a higher incidence of at-level allodynia. THE JOURNAL OF PAIN 2010; 11:864-75. [PMID: 20338826 DOI: 10.1016/j.jpain.2009.12.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 10/09/2009] [Accepted: 12/10/2009] [Indexed: 01/13/2023]
Abstract
UNLABELLED Approximately 70% of male rats receiving severe T8 spinal contusions develop allodynia in T5-7 dermatomes (at-level) beginning 2 weeks after injury. In contrast, rats having either complete transections or dorsal hemisections do not develop allodynia at-level after chronic spinal cord injury (SCI). In the present study, incomplete laceration and contusion injuries were made to test for neuroanatomical correlates between areas of white matter damage/sparing at the lesion epicenter and the presence/absence of allodynia. After incomplete laceration lesions and 6 weeks of behavioral testing, histological reconstruction and analysis of the lesion epicenters revealed a significant difference (P < .001) in the amount of ventrolateral funiculus (VLF) asymmetry between rats showing pain-like responses evoked by touch (74.5% +/- 8.4% side-to-side difference in VLF damage) versus those not responding to touch (11.3% +/- 4.4% side-to-side difference in VLF damage). A 5-week mean allodynia score for each rat that incorporates a full range of forces that are all innocuous in intact controls revealed that the degree of hypersensitivity at level is related to the extent of VLF asymmetry after SCI. No other damaged spinal white matter or gray matter area was correlated with sensitivity to touch. Similar findings were obtained for rats receiving T8 contusions, a more clinically relevant injury. These data suggest that different extents of damage/sparing between the 2 sides of VLF probably are a requisite for the development of allodynia after SCI. PERSPECTIVE A side-to-side lesion asymmetry after chronic SCI in a rodent model was found to be highly correlated with the presence and degree of allodynia. Greater insight of key factors contributing to the development and maintenance of chronic neuropathic pain is important for improving quality of life.
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Auvray M, Myin E, Spence C. The sensory-discriminative and affective-motivational aspects of pain. Neurosci Biobehav Rev 2010; 34:214-23. [PMID: 18718486 DOI: 10.1016/j.neubiorev.2008.07.008] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2007] [Revised: 07/23/2008] [Accepted: 07/23/2008] [Indexed: 11/27/2022]
Affiliation(s)
- Malika Auvray
- Crossmodal Research Laboratory, Department of Experimental Psychology, Oxford University, South Parks Road, Oxford OX1 3UD, UK.
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The cutaneous senses: touch, temperature, pain/itch, and pleasure. Neurosci Biobehav Rev 2009; 34:145-7. [PMID: 19732791 DOI: 10.1016/j.neubiorev.2009.08.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 08/13/2009] [Indexed: 11/24/2022]
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Peng HY, Chang HM, Lee SD, Huang PC, Chen GD, Lai CH, Lai CY, Chiu CH, Tung KC, Lin TB. TRPV1 mediates the uterine capsaicin-induced NMDA NR2B-dependent cross-organ reflex sensitization in anesthetized rats. Am J Physiol Renal Physiol 2008; 295:F1324-35. [DOI: 10.1152/ajprenal.00126.2008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Spinal cord-mediated cross-organ sensitization between the uterus and the lower urinary tract may underlie the high concurrence of obstetrical/gynecological inflammation and chronic pelvic pain syndrome characterized by urogenital pain. However, the neural pathway and the neurotransmitters involved are still unknown. We tested the hypothesis that the excitation of capsaicin-sensitive primary afferent fibers arising from the uterus through the stimulation of transient receptor potential vanilloid 1 (TRPV1) induces cross-organ sensitization on the pelvic-urethra reflex activity. Capsaicin (1–1,000 μM, 0.05 ml) was instilled into the uterus to induce cross-organ reflex sensitization. Activation of capsaicin-sensitive primary afferent fibers by capsaicin instillation into the uterine horn sensitized the pelvic-urethra reflex activity that was reversed by an intrauterine pretreatment with capsaizepine, a TRPV1-selective antagonist. Intrathecal injection of AP5, a glutamatergic N-methyl-d-aspartate (NMDA) antagonist, and Co-101244, an NMDA NR2B-selective antagonist, both abolished the cross-organ reflex sensitization caused by capsaicin instillation. These results demonstrated that TRPV1 plays a crucial role in contributing to the capsaicin-sensitive primary afferent fibers mediating the glutamatergic NMDA-dependent cross-organ sensitization between the uterus and the lower urinary tract when there is a tissue injury.
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Gallace A, Spence C. The science of interpersonal touch: an overview. Neurosci Biobehav Rev 2008; 34:246-59. [PMID: 18992276 DOI: 10.1016/j.neubiorev.2008.10.004] [Citation(s) in RCA: 315] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 09/12/2008] [Accepted: 10/01/2008] [Indexed: 01/13/2023]
Abstract
Surprisingly little scientific research has been conducted on the topic of interpersonal touch over the years, despite the importance of touch in our everyday social interactions from birth through to adulthood and old age. In this review, we critically evaluate the results of the research on this topic that have emerged from disciplines, such as cognitive and social psychology, neuroscience, and cultural anthropology. We highlight some of the most important advances to have been made in our understanding of this topic: For example, research has shown that interpersonal tactile stimulation provides an effective means of influencing people's social behaviors (such as modulating their tendency to comply with requests, in affecting people's attitudes toward specific services, in creating bonds between couples or groups, and in strengthening romantic relationships), regardless of whether or not the tactile contact itself can be remembered explicitly. What is more, interpersonal touch can be used to communicate emotion in a manner similar to that demonstrated previously in vision and audition. The recent growth of studies investigating the potential introduction of tactile sensations to long-distance communication technologies (by means of mediated or 'virtual' touch) are also reviewed briefly. Finally, we highlight the synergistic effort that will be needed by researchers in different disciplines if we are to develop a more complete understanding of interpersonal touch in the years to come.
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Affiliation(s)
- Alberto Gallace
- Department of Psychology, University of Milan-Bicocca, Milan, Italy.
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Peng HY, Huang PC, Liao JM, Tung KC, Lee SD, Cheng CL, Shyu JC, Lai CY, Chen GD, Lin TB. Estrous cycle variation of TRPV1-mediated cross-organ sensitization between uterus and NMDA-dependent pelvic-urethra reflex activity. Am J Physiol Endocrinol Metab 2008; 295:E559-68. [PMID: 18577691 DOI: 10.1152/ajpendo.90289.2008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cross-organ sensitization between the uterus and the lower urinary tract (LUT) underlies the high concurrence of pelvic pain syndrome and LUT dysfunctions, and yet the role of gonadal steroids is still unknown. We tested the hypothesis that cross-organ sensitization on pelvic-urethra reflex activity caused by uterine capsaicin instillation is estrous cycle dependent. When compared with the baseline reflex activity (1.00 +/- 0.00 spikes/stimulation), uterine capsaicin instillation significantly increased reflex activity (45.42 +/- 9.13 spikes/stimulation, P < 0.01, n = 7) that was corroborated by an increase in phosphorylated NMDA NR2B (P < 0.05, n = 4) but not NR2A subunit (P > 0.05, n = 4) expression. Both intrauterine pretreatment with capsazepine (5.02 +/- 2.11 spikes/stimulation, P < 0.01, n = 7) and an intrathecal injection of AP5 (3.21 +/- 0.83 spikes/stimulation, P < 0.01, n = 7) abolished the capsaicin-induced cross-organ sensitization and the increment in the phosphorylated NR2B level (P < 0.05, n = 4). The degrees of the cross-organ sensitization increased in a dose-dependent manner with the concentration of instilled capsaicin from 100 to 300 microM in both the proestrus and metestrus stages, whereas they weakened when the concentrations were higher than 1,000 microM. Moreover, the cross-organ sensitization caused by the uterine capsaicin instillation increased significantly in the rats during the proestrus stage when compared with the metestrus stage (P < 0.01, n = 7). These results suggest that estrogen levels might modulate the cross-organ sensitization between the uterus and the urethra and underlie the high concurrence of pelvic pain syndrome and LUT dysfunctions.
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Affiliation(s)
- Hsien-Yu Peng
- Dept. of Physiology, College of Medicine, Chung-Shan Medical University, Taichung, Taiwan 40201
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Nociceptive behavior in animal models for peripheral neuropathy: spinal and supraspinal mechanisms. Prog Neurobiol 2008; 86:22-47. [PMID: 18602968 DOI: 10.1016/j.pneurobio.2008.06.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 04/08/2008] [Accepted: 06/11/2008] [Indexed: 02/01/2023]
Abstract
Since the initial description by Wall [Wall, P.D., 1967. The laminar organization of dorsal horn and effects of descending impulses. J. Neurophysiol. 188, 403-423] of tonic descending inhibitory control of dorsal horn neurons, several studies have aimed to characterize the role of various brain centers in the control of nociceptive input to the spinal cord. The role of brainstem centers in pain inhibition has been well documented over the past four decades. Lesion to peripheral nerves results in hypersensitivity to mild tactile or cold stimuli (allodynia) and exaggerated response to nociceptive stimuli (hyperalgesia), both considered as cardinal signs of neuropathic pain. The increased interest in animal models for peripheral neuropathy has raised several questions concerning the rostral conduction of the neuropathic manifestations and the role of supraspinal centers, especially brainstem, in the inhibitory control or in the abnormal contribution to the maintenance and facilitation of neuropathic-like behavior. This review aims to summarize the data on the ascending and descending modulation of neuropathic manifestations and discusses the recent experimental data on the role of supraspinal centers in the control of neuropathic pain. In particular, the review emphasizes the importance of the reciprocal interconnections between the analgesic areas of the brainstem and the pain-related areas of the forebrain. The latter includes the cerebral limbic areas, the prefrontal cortex, the intralaminar thalamus and the hypothalamus and play a critical role in the control of pain considered as part of an integrated behavior related to emotions and various homeostatic regulations. We finally speculate that neuropathic pain, like extrapyramidal motor syndromes, reflects a disorder in the processing of somatosensory information.
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Weerakkody NS, Blouin JS, Taylor JL, Gandevia SC. Local subcutaneous and muscle pain impairs detection of passive movements at the human thumb. J Physiol 2008; 586:3183-93. [PMID: 18467366 DOI: 10.1113/jphysiol.2008.152942] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Activity in both muscle spindle endings and cutaneous stretch receptors contributes to the sensation of joint movement. The present experiments assessed whether muscle pain and subcutaneous pain distort proprioception in humans. The ability to detect the direction of passive movements at the interphalangeal joint of the thumb was measured when pain was induced experimentally in four sites: the flexor pollicis longus (FPL), the subcutaneous tissue overlying this muscle, the flexor carpi radialis (FCR) muscle and the subcutaneous tissue distal to the metacarpophalangeal joint of thumb. Tests were conducted when pain was at a similar subjective intensity. There was no significant difference in the ability to detect flexion or extension under any painful or non-painful condition. The detection of movement was significantly impaired when pain was induced in the FPL muscle, but pain in the FCR, a nearby muscle that does not act on the thumb, had no effect. Subcutaneous pain also significantly impaired movement detection when initiated in skin overlying the thumb, but not in skin overlying the FPL muscle in the forearm. These findings suggest that while both muscle and skin pain can disturb the detection of the direction of movement, the impairment is site-specific and involves regions and tissues that have a proprioceptive role at the joint. Also, pain induced in FPL did not significantly increase the perceived size of the thumb. Proprioceptive mechanisms signalling perceived body size are less disturbed by a relevant muscle nociceptive input than those subserving movement detection. The results highlight the complex relationship between nociceptive inputs and their influence on proprioception and motor control.
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Affiliation(s)
- N S Weerakkody
- Prince of Wales Medical Research Institute, Barker Street, Randwick, Sydney, NSW 2031, Australia
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Cothron KJ, Massey JM, Onifer SM, Hubscher CH. Identification of penile inputs to the rat gracile nucleus. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1015-23. [PMID: 18171689 DOI: 10.1152/ajpregu.00656.2007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurons in the medullary reticular formation (MRF) of the rat receive a vast array of urogenital inputs. Using select acute and chronic spinal cord lesions to identify the location of the ascending neural circuitries providing either direct or indirect inputs to MRF from the penis, our previous studies demonstrated that the dorsal columns and dorsal half of the lateral funiculus convey low- and high-threshold inputs, respectively. In the present study, the gracile nucleus was targeted as one of the likely sources of low-threshold information from the penis to MRF. Both electrophysiological recordings and neuroanatomical tracing [injection of cholera toxin B subunit (CTB) into a dorsal nerve of the penis] were used. After discrimination of a single neuron responding to penile stimulation, testing for somatovisceral convergence was done (mechanical stimulation of the distal colon and the skin over the entire hindquarters). In 12 rats, a limited number of neurons (43 in total) responded to penile stimulation. Many of these neurons also responded to scrotal stimulation (53.5%, dorsal and/or ventral scrotum) and/or prepuce stimulation (46.5%). Histological reconstruction of the electrode tracks showed that the majority of neurons responding to penile stimulation were located ventrally within the medial one-third of the gracile nucleus surrounding obex. This location corresponded to sparse innervation by CTB-immunoreactive primary afferent terminals. These results indicate that neurons in the gracile nucleus are likely part of the pathway that provides low-threshold penile inputs to MRF, a region known to play an important role in mating processes.
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Affiliation(s)
- Kyle J Cothron
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
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21
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Malykhina AP. Neural mechanisms of pelvic organ cross-sensitization. Neuroscience 2007; 149:660-72. [PMID: 17920206 DOI: 10.1016/j.neuroscience.2007.07.053] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 07/05/2007] [Accepted: 07/12/2007] [Indexed: 12/12/2022]
Abstract
Clinical observations of viscerovisceral referred pain in patients with gastrointestinal and genitourinary disorders suggest an overlap of neurohumoral mechanisms underlying both bowel and urinary bladder dysfunctions. Close proximity of visceral organs within the abdominal cavity complicates identification of the exact source of chronic pelvic pain, where it originates, and how it relocates with time. Cross-sensitization among pelvic structures may contribute to chronic pelvic pain of unknown etiology and involves convergent neural pathways of noxious stimulus transmission from two or more organs. Convergence of sensory information from discrete pelvic structures occurs at different levels of nervous system hierarchy including dorsal root ganglia, the spinal cord and the brain. The cell bodies of sensory neurons projecting to the colon, urinary bladder and male/female reproductive organs express a wide range of membrane receptors and synthesize many neurotransmitters and regulatory peptides. These substances are released from nerve terminals following enhanced neuronal excitability and may lead to the occurrence of neurogenic inflammation in the pelvis. Multiple factors including inflammation, nerve injury, ischemia, peripheral hyperalgesia, metabolic disorders and other pathological conditions dramatically alter the function of directly affected pelvic structures as well as organs located next to a damaged domain. Defining precise mechanisms of viscerovisceral cross-sensitization would have implications for the development of effective pharmacological therapies for the treatment of functional disorders with chronic pelvic pain such as irritable bowel syndrome and painful bladder syndrome. The complexity of overlapping neural pathways and possible mechanisms underlying pelvic organ crosstalk are analyzed in this review at both systemic and cellular levels.
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Affiliation(s)
- A P Malykhina
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA.
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Fromy B, Sigaudo-Roussel D, Baron C, Roquelaure Y, Leftheriotis G, Saumet JL. Neuroendocrine pathway involvement in the loss of the cutaneous pressure-induced vasodilatation during acute pain in rats. J Physiol 2006; 579:247-54. [PMID: 17158176 PMCID: PMC2075372 DOI: 10.1113/jphysiol.2006.121426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Pain is regarded as a risk factor in pressure ulcer development by contributing to immobility. Pressure-induced vasodilatation (PIV) is a mechanism whereby cutaneous blood flow increases in response to progressive locally applied pressure, thereby delaying the occurrence of ischaemia and appearing to be a protective response to local pressure. When the interaction between nervous and vascular systems is deregulated, PIV, which relies on both systems, is absent. We thus hypothesized that acute pain could alter PIV. This study investigated the effects on PIV of acute pain triggered by noxious heat (50 degrees C) applied to the tail of anaesthetized rats. To address the mechanisms underlying these effects, chronic sympathectomy was performed using guanethidine, and the plasma concentrations of pituitary adrenocorticotrophin (ACTH) and catecholamines were measured. Our results show that acute pain induces a loss of PIV associated with an increase of ACTH. Direct involvement of hypertensive effects and peripheral sympathetic nervous system are excluded in the loss of PIV, whereas the activation of brain structures that have descending inhibitory control cannot be excluded. A low dose of systemic morphine prevented this loss of PIV and maintained the ability of the cutaneous microcirculation to adapt to the applied pressure. The loss of a protective response to local pressure (PIV) induced by acute pain lends physiological support to the direct involvement of pain in pressure ulcer development. Therefore, an adequate evaluation and treatment of pain is crucial.
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Affiliation(s)
- Bérengère Fromy
- Integrative neuro-vascular biology, UMR CNRS 6214-INSERM 771, University of Angers, Rue Haute de Reculee, F-49045 Angers, France
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Winnard KP, Dmitrieva N, Berkley KJ. Cross-organ interactions between reproductive, gastrointestinal, and urinary tracts: modulation by estrous stage and involvement of the hypogastric nerve. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1592-601. [PMID: 16946082 DOI: 10.1152/ajpregu.00455.2006] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Central nervous system neurons process information converging from the uterus, colon, and bladder, partly via the hypogastric nerve. This processing is influenced by the estrous cycle, suggesting the existence of an estrous-modifiable central nervous system substrate by which input from one pelvic organ can influence functioning of other pelvic organs. Here, we tested predictions from this hypothesis that acute inflammation of colon, uterine horn, or bladder would produce signs of inflammation in the other uninflamed organs (increase vascular permeability) and that cross-organ effects would vary with estrous and be eliminated by hypogastric neurectomy (HYPX). Under urethane anesthesia, the colon, uterine horn, or bladder of rats in proestrus or metestrus, with or without prior HYPX, was treated with mustard oil or saline. Two hours later, Evans Blue dye extravasation was measured to assess vascular permeability. Extravasation was increased in all inflamed organs, regardless of estrous stage. For rats in proestrus, but not metestrus, either colon or uterine horn inflammation significantly increased extravasation in the uninflamed bladder. Much smaller cross-organ effects were seen in colon and uterine horn. HYPX reduced extravasation in the inflamed colon and inflamed uterine horn, but not the inflamed bladder. HYPX eliminated the colon-to-bladder and uterine horn-to-bladder effects. These results demonstrate that inflaming one pelvic organ can produce estrous-modifiable signs of inflammation in other pelvic organs, particularly bladder, and suggest that the cross-organ effects involve the hypogastric nerve and are at least partly centrally mediated. Such effects could contribute to cooccurrence and cyclicity of distressing pelvic disorders in women.
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Affiliation(s)
- Kenneth P Winnard
- Program in Neuroscience, Florida State University, Eppes Bldg., Copeland Street, Tallahassee, FL 32306-1270, USA
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Kaddumi EG, Hubscher CH. Changes in rat brainstem responsiveness to somatovisceral inputs following acute bladder irritation. Exp Neurol 2006; 203:349-57. [PMID: 17010973 DOI: 10.1016/j.expneurol.2006.08.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 07/14/2006] [Accepted: 08/17/2006] [Indexed: 12/27/2022]
Abstract
A number of clinical studies indicate the coexistence of multiple chronic pelvic diseases and pain syndromes. An association between various conditions related to the pelvic viscera may relate to a high degree of central visceral convergence, which is a requisite for the cross-organ coordination that is necessary for their normal functions. In the present study, a population of neurons receiving a high degree of somatovisceral convergence (those in the medullary reticular formation--MRF) was targeted in order to examine the effect of infusing a chemical irritant into one organ on the responsiveness of convergent inputs from various visceral and somatic regions of the body, using electrophysiological techniques. Acute irritation of the urinary bladder (UB) with 2% acetic acid significantly decreased the percentage of convergent MRF neuronal responses to UB distention and urethral infusion and significantly increased the percentage responding to whole body, mainly due to stimulation of the face. Irritation also produced a significant increase in the response duration of MRF neurons to distention of colon as well as the bladder (for those few UB responses that still remained). These results indicate that a pelvic/visceral pathology confined to one organ can affect at least some of the convergent responses from other regions of the body. The findings suggest that MRF neurons contribute to the cross-talk between different regions of the body under both normal and pathological conditions.
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Affiliation(s)
- Ezidin G Kaddumi
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA
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Morrison TC, Dmitrieva N, Winnard KP, Berkley KJ. Opposing viscerovisceral effects of surgically induced endometriosis and a control abdominal surgery on the rat bladder. Fertil Steril 2006; 86:1067-73. [PMID: 16962120 DOI: 10.1016/j.fertnstert.2006.03.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 03/20/2006] [Accepted: 03/20/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To determine, in rats, how surgically induced endometriosis and a control surgery (partial hysterectomy; sutures in abdomen) affects micturition thresholds and bladder vascular permeability. DESIGN Two animal studies, each performed in three groups of urethane-anesthetized rats in proestrus. SETTING Academic facility. ANIMAL(S) Seventy-three female, regularly cycling Sprague-Dawley rats studied in proestrus. INTERVENTION(S) Surgical induction of endometriosis (ENDO), surgical control (shamENDO), intact control (NoSURG), and bladder inflammation via intravesicular turpentine in all three groups. MAIN OUTCOME MEASURE(S) [1] Micturition thresholds (MTs; volume voiding thresholds), as measured by repetitive transurethral cystometry before and after bladder inflammation and [2] bladder inflammation, as assessed by extravasation of Evans Blue dye. RESULT(S) In the uninflamed bladder, MTs were significantly lower and dye extravasation significantly higher in ENDO rats than in shamENDO and NoSURG rats. Bladder inflammation increased dye extravasation in all groups and reduced MTs in the NoSURG and ENDO rats, but not in the shamENDO rats. CONCLUSION(S) Endometriosis reduces MTs and produces signs of inflammation in the healthy bladder. Surprisingly, the control surgical procedure (partial hysterectomy; sutures on mesenteric blood vessels) protects bladder reflexes from the influence of bladder inflammation, a condition that is named silent bladder inflammation. Such cross-system inducing and masking effects have important clinical relevance.
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Affiliation(s)
- Trevor C Morrison
- Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-1270, USA
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Hubscher CH. Estradiol-associated variation in responses of rostral medullary neurons to somatovisceral stimulation. Exp Neurol 2006; 200:227-39. [PMID: 16624305 DOI: 10.1016/j.expneurol.2006.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 01/09/2006] [Accepted: 02/10/2006] [Indexed: 11/30/2022]
Abstract
The lordosis posture and cervix stimulation during copulation are important reproductive events involving complex neural circuitries that are under hormonal influence. An important component of this circuitry, neurons within the medullary reticular formation (MRF), was examined in the present study using electrophysiological techniques. Single unit extracellular recordings were performed in the MRF of 27 urethane-anesthetized female rats. Using bilateral electrical stimulation of the dorsal nerve of the clitoris as the search stimulus, a detailed examination of the somatovisceral convergent responses of 585 individual MRF neurons was made. A total of 7 different groups of cycling and ovariectomized/hormone-supplemented rats were examined and their neuronal response properties to mechanical stimulation of various pelvic organs (cervix pressure, vaginal distension, colon distension) compared. The results indicate the existence of complex response properties as well as several variations in MRF response characteristics that are hormone-dependent. Specifically, estradiol is associated with hyposensitivity to cervix pressure and hypersensitivity to stroking the face. These opposing effects of estradiol in the same subset of neurons likely relate to lordosis behavior which can be either disrupted or elicited, depending on the area being stimulated (upper versus lower parts of the body, respectively).
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Affiliation(s)
- Charles H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA.
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Robbins MT, Uzzell TW, Aly S, Ness TJ. Characterization of thalamic neuronal responses to urinary bladder distention, including the effect of acute spinal lesions in the rat. THE JOURNAL OF PAIN 2006; 7:218-24. [PMID: 16516828 DOI: 10.1016/j.jpain.2005.10.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 10/25/2005] [Accepted: 10/27/2005] [Indexed: 10/25/2022]
Abstract
UNLABELLED Chronic visceral pain has proved to be difficult to treat. This study characterized urinary bladder distention (UBD)-evoked responses of neurons located within the ventrobasal group of the thalamus. Units were also characterized for responses to cutaneous stimuli and colorectal distention (CRD). In addition, the effects of spinal lesions on UBD-evoked responses were examined in a subset of neurons. After a stable response to UBD was established, 3 sequential lesions of the spinal cord at the mid-cervical level were performed, and responses to UBD were determined 1 and 5 minutes later. A majority of the neurons in the ventrobasal group of the thalamus were excited by UBD, demonstrated graded responses to graded distention pressures, and responded to cutaneous stimulation. No correlation between the magnitude of the responses of thalamic neurons to UBD and CRD was found. UBD-evoked thalamic neuronal activity was significantly attenuated after dorsal midline lesions of the spinal cord. The present study is a quantitative description of ventrobasal thalamic neuronal responses to UBD in the rat and provides direct neurophysiologic evidence that nociceptive information from the urinary bladder to the ventrobasal group of the thalamus ascends via a dorsal midline pathway. PERSPECTIVE The effect of dorsal midline lesions is of profound clinical interest because it points to a potential treatment for urinary bladder pain, such as that which is characteristic of interstitial cystitis. Further research might reveal pharmacologic approaches to modulate this pain pathway and result in novel treatments for interstitial cystitis.
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Affiliation(s)
- Meredith T Robbins
- Department of Anesthesiology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama 35294, USA.
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Kaddumi EG, Hubscher CH. Convergence of multiple pelvic organ inputs in the rat rostral medulla. J Physiol 2006; 572:393-405. [PMID: 16455688 PMCID: PMC1779668 DOI: 10.1113/jphysiol.2005.102574] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Accepted: 01/27/2006] [Indexed: 12/12/2022] Open
Abstract
Electrophysiological recordings were used to investigate the degree of pelvic/visceral convergent inputs onto single medullary reticular formation (MRF) neurons. A total of 94 MRF neurons responsive to bilateral electrical stimulation of the pelvic nerve (PN) in 12 urethane-anaesthetized male rats were tested for responses to mechanical stimulation of the urinary bladder, urethra, colon and penis, and electrical stimulation of the dorsal nerve of the penis (DNP) and abdominal branches of the vagus. Responses to distension of the bladder were found for 51% (n = 48) of the MRF neurons tested. Of these 48, 71% responded to urethral infusion, 81% responded to colon distension, 100% responded to penile stimulation (and DNP), and 85% responded to vagal stimulation, with 62% responding to stimulation of all four of these territories. This high degree of visceral convergence (i.e. 62%) in a subset of PN-responsive MRF neurons is significantly greater than for the subset of PN-responsive MRF neurons that did not respond to urinary bladder distension (i.e. out of the 46 remaining neurons, none responded to all four of the other pelvic/visceral stimuli combined). These results suggest that the neurons processing information from the urinary bladder at this level of the neural axis are likely to be important for mediating interactions between different visceral organs for the coordination of multiple pelvic/visceral functions.
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Affiliation(s)
- Ezidin G Kaddumi
- Department of Anatomical Sciences and Neurobiology, University of Louisville, KY 40292, USA
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Villanueva L, Lopez-Avila A, Monconduit L. Chapter 8 Ascending nociceptive pathways. HANDBOOK OF CLINICAL NEUROLOGY 2006; 81:93-102. [PMID: 18808830 DOI: 10.1016/s0072-9752(06)80012-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Hubscher CH. Ascending spinal pathways from sexual organs: effects of chronic spinal lesions. AUTONOMIC DYSFUNCTION AFTER SPINAL CORD INJURY 2006; 152:401-14. [PMID: 16198716 DOI: 10.1016/s0079-6123(05)52027-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A recent survey of paraplegics indicates that regaining sexual function is of the highest priority for both males and females (Anderson, K.D. (2004) Targeting recovery: priorities of the spinal cord-injured population J. Newrotrauma, 21: 1371-1383). Our understanding of the neural pathways and mechanisms underlying sexual behavior and function is limited at the present time. More studies are obviously needed to direct experiments geared toward developing effective therapeutic interventions. In this chapter, a review of studies on the processing of sensory inputs from the male and female reproductive organs is presented with a review of what is known about the location of ascending spinal pathways conveying this information. The effect of spinal cord injury on sexual function and the problems that ensue are discussed.
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Affiliation(s)
- Charles H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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Hubscher CH, Johnson RD. Chronic spinal cord injury induced changes in the responses of thalamic neurons. Exp Neurol 2006; 197:177-88. [PMID: 16266704 DOI: 10.1016/j.expneurol.2005.09.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 08/16/2005] [Accepted: 09/08/2005] [Indexed: 11/22/2022]
Abstract
Sensory disturbances following spinal cord injury (SCI) include chronic pain, which is often localized at spinal levels just rostral to the lesion (referred to as at-level neuropathic pain) and not effectively relieved by traditional treatments. In the present study, a clinically relevant spinal contusion injury was made at the spinal T8 level in 11 deeply anesthetized male rats. Behavioral testing just prior to terminal electrophysiological experiments (done at 30 days post-injury) demonstrated at-level sensitivity to touching the trunk (i.e., allodynia) in 64% of the animals. Electrophysiological data (urethane anesthesia) were obtained for 218 single somatovisceral convergent neurons that were located throughout 12 subregions of the thalamus. In total, 90% (197 of 218) responded to noxious at-level pinch, compared to 52% for pinching the dorsal trunk at the same level in uninjured controls (our previously published data--recorded from 133 total neurons). In addition, 33% of the total neurons tested also responded to gentle touch (dorsal trunk) versus 9% in controls. A comparison of electrophysiological and behavioral data for each individual animal reveals novel tactile neuronal responses within ventral and posterior thalamic subnuclei for those rats showing signs of at-level allodynia. These data suggest that neurons in specific regions of thalamus undergo significant changes in responsiveness following severe chronic SCI. The observed plasticity and ensuing hypersensitivity are likely part of the central reorganization producing the multitude of sensory disturbances that surface following SCI.
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Affiliation(s)
- Charles H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA.
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Abstract
A large body of literature indicates that cannabinoids suppress behavioral responses to acute and persistent noxious stimulation in animals. This review examines neuroanatomical, behavioral, and neurophysiological evidence supporting a role for cannabinoids in suppressing pain at spinal, supraspinal, and peripheral levels. Localization studies employing receptor binding and quantitative autoradiography, immunocytochemistry, and in situ hybridization are reviewed to examine the distribution of cannabinoid receptors at these levels and provide a neuroanatomical framework with which to understand the roles of endogenous cannabinoids in sensory processing. Pharmacological and transgenic approaches that have been used to study cannabinoid antinociceptive mechanisms are described. These studies provide insight into the functional roles of cannabinoid CB1 (CB1R) and CB2 (CB2R) receptor subtypes in cannabinoid antinociceptive mechanisms, as revealed in animal models of acute and persistent pain. The role of endocannabinoids and related fatty acid amides that are implicated in endogenous mechanisms for pain suppression are discussed. Human studies evaluating therapeutic potential of cannabinoid pharmacotherapies in experimental and clinical pain syndromes are evaluated. The potential of exploiting cannabinoid antinociceptive mechanisms in novel pharmacotherapies for pain is discussed.
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MESH Headings
- Animals
- Cannabinoid Receptor Modulators/physiology
- Cannabinoids/pharmacology
- Cannabinoids/therapeutic use
- Humans
- Hyperalgesia/physiopathology
- Nociceptors/physiology
- Pain/drug therapy
- Pain/physiopathology
- RNA, Messenger/analysis
- Receptor, Cannabinoid, CB1/analysis
- Receptor, Cannabinoid, CB1/drug effects
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/physiology
- Receptor, Cannabinoid, CB2/drug effects
- Receptor, Cannabinoid, CB2/physiology
- Spinal Cord/drug effects
- Spinal Cord/physiology
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Affiliation(s)
- J M Walker
- Department of Psychology, Indiana University Bloomington, IN 47405-7007, USA
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33
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Kitagawa J, Tsuboi Y, Ogawa A, Ren K, Hitomi S, Saitoh K, Takahashi O, Masuda Y, Harada T, Hanzawa N, Kanda K, Iwata K. Involvement of Dorsal Column Nucleus Neurons in Nociceptive Transmission in Aged Rats. J Neurophysiol 2005; 94:4178-87. [PMID: 16293592 DOI: 10.1152/jn.00243.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To clarify the functional role of the dorsal column nucleus (DCN) in nociception in rats with advancing age, single neuronal activity and substance P–like immunoreactivity (SP-LI) of the gracile nucleus (GN) were studied in aged rats (29 to 34 mo old) and adult rats (9 to 12 mo old). A total of 122 neurons [aged: 34 wide-dynamic-range (WDR), two nociceptive-specific (NS), and 32 low-threshold mechanical (LTM) neurons; adult: 22 WDR and 32 LTM neurons] were recorded from GN. For WDR neurons, the latency to antidromic activation of the ventral posterior lateral nucleus of the thalamus showed no difference between the aged and adult rats. Sciatic nerve stimulation with C-fiber intensity induced responses of GN with significantly longer latency in aged rats than in adults, whereas there was no difference in the response latency to A-fiber intensity stimulation. Background activity and afterdischarges were significantly higher in the aged rats than those in the adult rats. Responses to noxious mechanical and thermal stimuli were significantly greater in the aged rats during application of graded stimuli. There were no significant differences in responses to nonnoxious mechanical stimulus, mechanical response threshold, and the size of the receptive fields between neurons in the aged and adult rats. The area occupied by SP-LI fibers in the GN and the size of SP-LI dorsal root ganglia neurons were significantly larger in aged rats than in adults. The present findings suggest that the hyperexcitability of GN neurons could be involved in abnormal noxious pain sensations with advancing age.
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Affiliation(s)
- Junichi Kitagawa
- Department of Physiology, School of Dentistry, Nihon University, Chiyoda-ku, Tokyo, Japan
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34
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Abstract
Despite the many advances in our understanding of the mechanisms underlying pain processing, pain continues to be a major healthcare problem in the United States. Each day, millions of Americans are affected by both acute and chronic pain conditions, costing in excess of $100 billion for treatment-related costs and lost work productivity. Thus, it is imperative that better treatment strategies be developed. One step toward improving pain management is through increased knowledge of pain physiology. Within the nervous system, there are several pathways that transmit information about pain from the periphery to the brain. There is also a network of pathways that carry modulatory signals from the brain and brainstem that alter the incoming flow of pain information. This article provides a review to the physiology and processing of pain.
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Affiliation(s)
- Cynthia L Renn
- Department of Organizational Systems and Adult Health, School of Nursing, University of Maryland, Baltimore, Maryland 21201-1579, USA.
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35
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Hubscher CH, Johnson RD. Effects of Chronic Dorsal Column Lesions on Pelvic Viscerosomatic Convergent Medullary Reticular Formation Neurons. J Neurophysiol 2004; 92:3596-600. [PMID: 15282259 DOI: 10.1152/jn.00310.2004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Single medullary reticular formation (MRF) neurons receive multiple somatovisceral convergent inputs originating from many different spinal and cranial nerves, including the pelvic nerve (PN), dorsal nerve of the penis (DNP), and the abdominal branches of the vagus. In a previous study, the input to MRF from the male genitalia was shown to be eliminated with chronic 30-day dorsal hemisection at the T8 spinal level. In this study, the effect of a smaller chronic lesion [dorsal column lesion (DCx)] on MRF neuronal responses was examined. Responses to bilateral electrical stimulation of the DNP remained. MRF neuronal responses to non-noxious (touch/stroke) levels of penile stimulation, however, were eliminated; only responses to noxious pinch remained. No differences were found for the number of neurons responding to noxious distention of the colon between the DCx and control groups. Although no differences were found across these groups for the percent MRF responses to vagal stimulation, the mean response latency for the DCx group was twice the sham-DCx/intact control group. Taken together, these results indicate that the MRF receives at least some of its input from the male genitalia via pathways located within the dorsal columns at the mid-thoracic spinal level.
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Affiliation(s)
- Charles H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40292, USA.
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36
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Abstract
The generation of neuropathic pain is a complex phenomenon involving a process of peripheral and central sensitization producing enhanced transmission of nociceptive inputs to the brain associated with the loss of discriminatory processing of noxious and innocuous stimuli. This increased flow of abnormally processed nociceptive inputs to the brain may overcome the ability of descending modulatory pathways to produce analgesia, causing further worsening of the pain. Several crucial locations involved in the physiologic generation of pain inputs (eg, peripheral nociceptors, dorsal horns, thalamus, cortex) show evidence of functional reorganization and altered nociceptive processing in association with chronic pain. These locations present the best targets for therapeutic intervention, including systemic administration of drugs able to counteract the chemical storm induced by neural injuries in the nociceptive afferents and dorsal horns, or for more focused intervention, such as neuroablative procedures; intrathecal drug delivery; and spinal cord, deep brain, or motor cortex stimulation.
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Affiliation(s)
- Pantaleo Romanelli
- Epilepsy Surgery Unit, Department of Neurosurgery, Neuromed IRCCS, Pozzilli, Italy.
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37
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Rong PJ, Zhang JL, Zhang HQ. Interactions between tactile and noxious visceral inputs in rat nucleus gracilus. Neurosci Lett 2004; 362:162-5. [PMID: 15193777 DOI: 10.1016/j.neulet.2004.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 03/10/2004] [Accepted: 03/12/2004] [Indexed: 02/08/2023]
Abstract
Recent studies have revealed that noxious visceral inputs travel in the dorsal column pathway, and interactions between colorectal noxious and tactile inputs occur in the ventrobasal thalamus. This investigation was to test whether the somatovisceral interactions also take place at a lower level in the dorsal column nuclei. Extracellular single neuron recordings were carried out in nucleus gracilus of anesthetized rats. Forty-three neurons responsive to colorectal distension (CRD) all had excitatory responses to tactile stimuli, and their tactile responses were predominantly (31/43 units) enhanced by preceding CRD. In contrast, the neuronal responses to CRD were reduced in 22/43 units when preceded by tactile stimulation but in two units there was an enhancement. The similarity and differences in the gracile response features in comparison with the thalamic recordings suggest that somatovisceral interactions take place at multiple levels in the dorsal column-medial lemniscus system.
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Affiliation(s)
- Pei-Jing Rong
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
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38
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Hwang SL, Lin CL, Lieu AS, Kuo TH, Yu KL, Ou-Yang F, Wang SN, Lee KT, Howng SL. Punctate midline myelotomy for intractable visceral pain caused by hepatobiliary or pancreatic cancer. J Pain Symptom Manage 2004; 27:79-84. [PMID: 14711472 DOI: 10.1016/j.jpainsymman.2003.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The purpose of this study was to demonstrate the existence of a newly recognized midline posterior column pathway that mediates the perception of visceral pain resulting from hepatobiliary or pancreatic cancer. A punctate midline myelotomy (PMM) of T(3) level was performed in 6 patients who experienced severe visceral pain caused by hepatobiliary or pancreatic cancer. Preoperatively, the pain was refractory to strong opioids. Clinical efficacy of PMM was evaluated by comparing patient pain rating on a visual analogue scale. Follow-up periods ranged from 2-18 weeks after operation. All 6 patients had immediate pain relief after operation. Although the pain recurred from 2-12 weeks later in 3 patients, the severity of recurrent cancer pain markedly decreased. No adverse neurological sequelae were observed. Our results of high thoracic PMM offer clinical support for the concept that neurosurgical interruption of midline visceral pain pathway can effectively control severe visceral pain without causing adverse neurological sequelae in patients with hepatobiliary or pancreatic cancer.
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Affiliation(s)
- Shiuh-Lin Hwang
- Division of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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39
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Abstract
The specificity theory of somesthesis holds that perceptions of warmth, cold, and pain are served by separate senses. Although no longer accepted in all its details, the theory's basic assumptions of anatomical and functional specificity have remained guiding principles in research on temperature perception and its relationship to pain. This article reviews the response characteristics of thermoreceptors, temperature-sensitive nociceptors, and their associated pathways in the context of old and new perceptual phenomena, most of which cannot be satisfactorily explained by the specificity theory. The evidence indicates that throughout most of the perceptual range, temperature sensitivity depends upon coactivation of, and interactions among, thermal and nociceptive pathways that are composed of both specific "labeled lines" and nonspecific, multimodal fibers. Adding to this complexity is evidence that tactile stimulation can influence the way in which thermal stimulation is perceived. It is argued that thermoreception is best defined as a functional subsystem of somesthesis that serves the very different and sometimes conflicting demands of thermoregulation, protection from thermal injury, and haptic perception.
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Affiliation(s)
- Barry G Green
- The John B. Pierce Laboratory and Department of Surgery (Otolaryngology), Yale School of Medicine, 290 Congress Avenue, New Haven, Connecticut 06519, USA.
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40
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Bradshaw HB, Berkley KJ. The influence of ovariectomy with or without estrogen replacement on responses of rat gracile nucleus neurons to stimulation of hindquarter skin and pelvic viscera. Brain Res 2003; 986:82-90. [PMID: 12965232 DOI: 10.1016/s0006-8993(03)03175-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Responses of neurons in the gracile nucleus (NG) of female rats to tactile and visceral stimulation change across the estrous cycle [J. Neurosci. 20 (2000) 7722]. To investigate estrogen's role in these changes, responses of NG neurons to tactile and visceral stimuli were examined in three groups: ovariectomized (OVX), OVX with estrogen replacement (OVX+E2), or sham OVX (tested in diestrus; shamOVX-D). The stimuli were: gentle brushing of hindquarter skin, pressure on the cervix, and distention of the uterus, vagina, or colon. After OVX, the magnitude of multi-unit responses to brushing the perineum, hip and tail, but not the foot and leg, were significantly reduced relative to shamOVX-D. OVX+E2 restored this magnitude to the same level as shamOVX-D, but not, as expected, to levels as large as previously observed in proestrus. After OVX, responses of single neurons to stimulation of the uterus, cervix, and colon were more likely to be excitatory (versus inhibitory) than they had been in cycling rats in proestrus (uterus, cervix) or diestrus (colon); OVX+E2 did not restore the inhibitory responses. In contrast, whereas all responses to vaginal distention after OVX were also excitatory, OVX+E2 in this case significantly restored the inhibitory responses. These findings provide further support for the conclusion that response characteristics of NG neurons are influenced by the rat's hormonal milieu, but also indicate that the influences are not a simple reflection of estrogen levels. The findings further suggest that NG is a component of neural systems that contribute to both reproductive behaviors and vaginal nociception.
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Affiliation(s)
- Heather B Bradshaw
- Program in Neuroscience, Florida State University, Copeland Street, Tallahassee, FL 32306-1270, USA
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41
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Chang DS, Lin CL, Lieu AS, Cheng CY, Wu SC, Hung MH, Loh JK, Kuo TH, Howng SL, Hwang SL. High cervical midline punctate myelotomy in the management of visceral pain in the mouse. Kaohsiung J Med Sci 2003; 19:159-62. [PMID: 12795344 DOI: 10.1016/s1607-551x(09)70465-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Increasing evidence implies the existence of a visceral pain pathway in the dorsal column of the spinal cord. Limited midline myelotomy has been used to treat intractable pelvic cancer pain. However, no obvious evidence has been provided that high cervical punctate midline myelotomy (CPMM) relieves visceral pain originating from the abdomen. This study was designed to examine the pain relief effect of CPMM in a mouse model of visceral pain. Thirty-six Institute of Cancer Research (ICR) mice were divided into three groups: Group 1, healthy controls; Group 2, treated with CPMM at C1 and C2; and Group 3, a sham group that underwent laminectomy at C1 and C2 without CPMM. All animals were tested for antinociception in the writhing test 24 hours after surgery. Visceral pain-related behaviors were counted from 5-20 minutes after intraperitoneal injection of 0.6% acetic acid. Writhing test scores were not significantly different between Groups 1 (56.7 +/- 10.7) and 3 (50.7 +/- 17.4). However, Group 2 (30.0 +/- 14.3) showed more than 40% antinociception after treatment, and writhing test scores were significantly different from those of Groups 1 and 3 (p < 0.001). Our results confirm that midline punctate myelotomy can relieve visceral pain and imply that there is a pathway in the posterior funiculus that signals visceral pain. Punctate midline myelotomy at the cervical or high thoracic level may be an alternative strategy in the management of intractable visceral pain due to abdominal or pelvic cancers.
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Affiliation(s)
- Dyi-Sheng Chang
- Division of Neurosurgery, Armed Forces Taichung General Hospital, Kaohsiung, Taiwan
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42
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Zhang HQ, Rong PJ, Zhang SP, Al-Chaer ED, Willis WD. Noxious visceral inputs enhance cutaneous tactile response in rat thalamus. Neurosci Lett 2003; 336:109-12. [PMID: 12499052 DOI: 10.1016/s0304-3940(02)01243-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The current study investigates whether visceral nociceptive inputs affect tactile processing in the thalamic ventroposterior lateral nucleus in anesthetized rats by means of extracellular single unit recordings. Twenty out of the 44 neurons had their response to tactile stimulation increased by preceding nociceptive colorectal distension (CRD), and this influence appear more potent than the opposite effect, tactile on CRD response. There was a dynamic change of tactile response along with CRD response and the background activities as a function of repeated colorectal stimulation. The abnormal neuronal discharge in response to tactile stimulation in the condition of visceral nociception could contribute to the development of referred pain and allodynia.
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Affiliation(s)
- Hong-Qi Zhang
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
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43
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Abstract
There have been relatively few electrophysiological studies, in any species, describing the supraspinal processing of inputs from the male genital tract. The thalamus was the focus of the present study. In 11 urethan-anesthetized male rats, subregions of the thalamus were surveyed for neuronal responses to the search stimulus, bilateral electrical stimulation of the dorsal nerve of the penis (DNP). A total of 133 DNP-responsive neurons were found and further tested for degree of somatovisceral convergence from other peripheral structures. Histological reconstruction of the recording sites revealed that the penile-responsive neurons were distributed among various thalamic subregions. These thalamic subregions included the medial-dorsal nuclei and ventral and lateral thalamic subregions (majority of neurons responsive to both tactile and pinch stimulation of the penis) as well as intralaminar, posterior and reticular subregions (majority responsive to pinch only). Taken together, the data demonstrate the existence of thalamic neurons with inputs from the male genitalia with widespread somatovisceral convergence. These neurons likely contribute to the neural circuitries underlying various aspects of penile sensation associated with reproductive and nociceptive events.
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Affiliation(s)
- Charles H Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Kentucky 40292, USA.
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44
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Abstract
Prevention of nerve injury-induced tactile, but not thermal, hypersensitivity is achieved by ipsilateral lesions of the dorsal columns or lidocaine microinjection into the nucleus gracilis (n. gracilis). These and other data support the possibility that tactile hyperresponsiveness after nerve injury may be selectively mediated by a low-threshold myelinated fiber pathway to the n. gracilis. Here we identify a transmitter that might selectively mediate such injury-induced tactile hypersensitivity. Neuropeptide Y (NPY), normally not detected in the dorsal root ganglion (DRG) or in the n. gracilis of rats, became markedly upregulated at both sites and in the spinal cord after spinal nerve injury. Injury-induced NPY-IR occurred predominately in large-diameter DRG cells, and the NPY-IR in the n. gracilis was blocked by dorsal rhizotomy or dorsal column lesion. NPY microinjection into the n. gracilis of uninjured rats elicited reversible tactile, but not thermal, hypersensitivity only in the ipsilateral hindpaw. Administration of anti-NPY antiserum, but not control serum or preabsorbed serum, into the n. gracilis ipsilateral to nerve injury reversed tactile, but not thermal, hypersensitivity. Similarly, microinjection of the NPY antagonists NPY(18-36) and (R)-N-[[4-(aminocarbonylaminomethyl)-phenyl]methyl]-N2-(diphenylacetyl)-argininamide trifluoroacetate, into the n. gracilis ipsilateral to the injury reversed tactile, but not thermal, hypersensitivity. Antagonist administration into the contralateral n. gracilis had no effect on injury-induced hypersensitivity. These data suggest the selective mediation of nerve injury-induced tactile hypersensitivity by upregulated NPY via large fiber input to n. gracilis. Selective reversal of injury-induced tactile allodynia by NPY receptor antagonists would have significant implications for human neuropathic conditions.
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45
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Zhang HQ, Al-Chaer ED, Willis WD. Effect of tactile inputs on thalamic responses to noxious colorectal distension in rat. J Neurophysiol 2002; 88:1185-96. [PMID: 12205140 DOI: 10.1152/jn.2002.88.3.1185] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent discoveries of visceral nociceptive inputs sharing the classical tactile pathway in the dorsal-column medial lemniscus system have opened a new venue for the investigation of somatovisceral interactions. The current study was designed to determine whether somatic innocuous inputs modulate visceral nociceptive transmission at the thalamic level. The investigation was carried out by means of extracellular single-unit recordings in the ventroposterior lateral nucleus of the thalamus in rats anesthetized with pentobarbital. Noxious visceral stimulation was achieved by reproducible colorectal distension (CRD, 20-80 mmHg) with a balloon catheter. Tactile stimulation was delivered by means of a feedback-controlled mechanical stimulator. The response of the neurons to CRD was compared before and after the conditioning procedure by giving tactile stimulation either immediately before CRD or overlapping it. Twenty-five ventroposterior lateral (VPL) thalamic neurons were found among numerous tactile-only neurons to have convergent inputs from both tactile and visceral sources. Their responses to CRD were excitatory (19), inhibitory (4), or bimodal. When cutaneous tactile stimuli were delivered before CRD, the responses were reduced in 18 cases. The reduction, however, was usually short-lasting, immediately following tactile stimulation and could not be enhanced by a prolonged conditioning procedure. It was unlikely to be attributable to neuronal habituation as the inverted procedure, CRD stimulation before tactile, often produced the opposite effect, that is, an enhanced response to skin stimulation. Repeated CRD could bring about sensitization of the responses of thalamic neurons as manifested by increased spontaneous discharge, lowered response threshold, and increased response level. Under such circumstances, the original effect of tactile stimulation on CRD responses could be weakened. In conclusion, tactile stimulation may in most circumstances inhibit thalamic neuronal responses to visceral nociceptive input produced by CRD. However, the effect appears to be mild and short-lasting at the individual neuronal level in the VPL thalamus.
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Affiliation(s)
- Hong-Qi Zhang
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
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46
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Hubscher CH, Johnson RD. Differential effects of chronic spinal hemisection on somatic and visceral inputs to caudal brainstem. Brain Res 2002; 947:234-42. [PMID: 12176166 DOI: 10.1016/s0006-8993(02)02930-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The medullary reticular formation (MRF) receives convergent inputs from multiple somatic and pelvic/visceral territories. The effects of chronic 30-day lateral hemisections at T8 on the responses of single MRF neurons to noxious mechanical stimulation of both hindpaws was examined in urethane-anesthetized male rats. Neuronal responses on both sides of the MRF to pinching of the hindpaw on the side opposite the lesion (intact-side) were found either to be completely absent or if present, weak (i.e. hindpaw was hyposensitive). The presence or absence of intact-side responses appeared to be dependent on the lesion extent. In contrast, bilateral MRF responses to pinching the lesion-side hindpaw were present; however, responses were greater in magnitude (lower thresholds) relative to surgical sham controls suggesting hypersensitivity. Responses to lesion-side hindpaw stimulation on both sides of the MRF indicated that whereas the ascending projections are primarily crossed below the level of lesion, they are both crossed and uncrossed above. These findings are in contrast with our previous data on ascending projections from the bilaterally organized male urogenital tract. The results presented for the hindpaws correlate with clinical observations of patients with similar incomplete spinal cord injuries (Brown-Séquard syndrome).
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Affiliation(s)
- Charles H Hubscher
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA.
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47
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Lue JH, Leong SM, Day AS, Tsai YJ, Shieh JY, Wen CY. Changes in c-Fos protein expression in the rat cuneate nucleus after electric stimulation of the transected median nerve. J Neurotrauma 2002; 19:897-907. [PMID: 12184859 DOI: 10.1089/08977150260190483] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this study we investigate temporal changes in Fos expression in cuneate neurons after a high-threshold electrical stimulation of the transected median nerve in rats. Two hours after injury of the median nerve when given electrical stimulation, c-Fos-immunoreactive (c-Fos-IR) cells were barely detected in the ipsilateral cuneate nucleus (CN). A few c-Fos-IR cells, however, were observed in the ipsilateral CN at 5 days. A marked increase in c-Fos-IR cells was observed at 2, 3, and 4 weeks, but levels subsided thereafter. Labeled cells were totally diminished by 16 weeks. The statistical analysis showed that the mean density of c-Fos-IR cells throughout the CN at 4 weeks was significantly higher than at other post-surgical time points, except for 3 weeks. Furthermore, the mean density of c-Fos-IR cells in the middle region of the CN was markedly higher than in other areas of the nucleus. The mean density of c-Fos-IR cells in the middle region at 4 weeks (mean density = 35.9 +/- 3.0 cells/section) was considerably higher than at other time points. Combined retrograde Fluorogold (FG) labeling and c-Fos immunocytochemistry showed that throughout the CN about 60% (2270/3652) of the c-Fos-IR cells contained FG, confirming that they were cuneothalamic projection neurons (CTNs). Moreover, the percentage of double-labeled cells in the middle region at 2 weeks (78.9 +/- 0.6%) was significantly greater than at 3 (70.2 +/- 3.4%) and 4 weeks (66.0b +/- 1.4%) after injury. Although the mechanism leading to the vigorous c-Fos expression in the CTNs following the electrical stimulation of the transected median nerve remains unclear the hyperexcitable CTNs may transmit the neuropathic nociceptive sensation to the thalamus after the median nerve injury.
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Affiliation(s)
- June-Horng Lue
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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48
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Abstract
Multi- and single-unit recording was performed in the gracile nucleus in urethane-anesthetized rats to examine estrous variations in responses of its neurons to brushing the hindquarters and mechanical stimulation of the uterus, vaginal canal, cervix, and colon. Six rats each were studied in each of the four estrous stages: proestrus (P), estrus (E), metestrus (M), and diestrus (D). The magnitude of multi-unit responses to gentle brushing of the perineum, hip, and tail, but not the foot and leg, was significantly greater during proestrus than during other stages. Of 70 single units responsive to brush, 56 (80%) responded to stimulation of at least one viscus. Although this percentage did not change with estrous stage, the direction and latency of some responses did. Pressure on the cervix evoked significantly more inhibitory (vs excitatory) responses in P than in E and M, and the response latency was significantly longer in D and P than in E and M. The direction of response to vaginal distention did not change with estrous stage, but response latency was significantly longer in D than in P and E. Uterine distention evoked significantly more inhibitory responses in D than in P, with no estrous changes in latency. Responses to colon distention did not change. These variations in both magnitude of response to tactile stimulation and characteristics of response to stimulation of reproductive organs, but not the colon, correlate with changes in mating behaviors of the female rat, suggesting that the gracile nucleus is a component of neural systems that control reproductive behaviors.
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49
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Day AS, Lue JH, Sun WZ, Shieh JY, Wen CY. A beta-fiber intensity stimulation of chronically constricted median nerve induces c-fos expression in thalamic projection neurons of the cuneate nucleus in rats with behavioral signs of neuropathic pain. Brain Res 2001; 895:194-203. [PMID: 11259778 DOI: 10.1016/s0006-8993(01)02095-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study was aimed to investigate the possible involvement of neurons in the cuneate nucleus (CN) in the processing of A beta afferent inputs evoked by electrical stimulation of constricted median nerve in rats with behavioral signs of neuropathic pain. Immunohistochemical localization of Fos protein was used to examine the neuronal activation, and the combination of Fos immunohistochemistry with the retrograde labeling of Fluoro-Gold (FG) injected into the ventrobasal complex of the thalamus was used to characterize the activated neurons. Two weeks after unilateral median nerve constriction injury, the rats exhibited behavioral signs of neuropathic pain in the affected forepaws. In rats after nerve injury but without electrical stimulation, some Fos-like immunoreactive (Fos-LI) neurons were detected in the dorsal horn of the seventh cervical segment (C7) but none was found in the CN. Similar features were also noted when the stimulation of the intact median nerve served as an additional control. After A beta-fiber intensity stimulation of the previously constricted median nerve, an increase in number of Fos-LI neurons occurred in the medial half of the ipsilateral C7 dorsal horn as well as in the ipsilateral CN. In the latter, the Fos-LI neurons were located in the median nerve projection territory throughout the nucleus. Most of the Fos-LI neurons were distributed in the middle region of the CN, with about 78% of them emitting FG fluorescence indicating that they were cuneothalamic projection neurons. The results of this study suggest that the dorsal column-medial lemniscal system may contribute to the transmission and modulation of A beta-fiber mediated neuropathic pain signals.
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Affiliation(s)
- A S Day
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Section 1, Jen-Ai Road, Taipei 100, Taiwan
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Abstract
A midline dorsal column lesion has been shown to be an effective surgical treatment for the relief of pelvic visceral pain in patients. The aim of this study was to examine the effectiveness of a dorsal column lesion upon: (i) increased electrophysiological responses of neurons in the ventral posterolateral thalamic nucleus in anesthetized rats evoked by the application of bradykinin to the surface of the pancreas, and (ii) pain-related behaviors observed after pancreatic infusion with bradykinin. In rats anesthetized with pentobarbital, recordings from individual thalamic neurons were made using tungsten electrodes. Brief application of bradykinin (10 microg/ml) to the surface of the pancreas resulted in an increased firing rate in approximately 20% of neurons recorded. A dorsal column lesion or intrathecal administration of morphine greatly reduced the excitatory effects of pancreatic bradykinin application on thalamic neurons. In a separate group of rats, bradykinin was infused into the pancreas through a previously implanted catheter resulting in a decrease in exploratory behavior and an increase in other pain-related behaviors, e.g. licking of the abdomen. A dorsal column lesion made prior (1 week) to the bradykinin infusion reduced the decrease in exploratory behavior but did not return exploratory behavior to control levels. In conclusion, nociceptive information relayed to the thalamus about the pancreas is transmitted from the spinal cord through the dorsal columns, possibly by the post-synaptic dorsal column pathway. However, the dorsal column pathway may not be the sole route for relaying information about noxious stimulation of the pancreas, particularly that impacting complex behavioral responses.
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Affiliation(s)
- A K Houghton
- Department of Anatomy and Neurosciences, Marine Biomedical Institute, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069, USA
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