1
|
Münzberg H, Berthoud HR, Neuhuber WL. Sensory spinal interoceptive pathways and energy balance regulation. Mol Metab 2023; 78:101817. [PMID: 37806487 PMCID: PMC10590858 DOI: 10.1016/j.molmet.2023.101817] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/10/2023] Open
Abstract
Interoception plays an important role in homeostatic regulation of energy intake and metabolism. Major interoceptive pathways include gut-to-brain and adipose tissue-to brain signaling via vagal sensory nerves and hormones, such as leptin. However, signaling via spinal sensory neurons is rapidly emerging as an additional important signaling pathway. Here we provide an in-depth review of the known anatomy and functions of spinal sensory pathways and discuss potential mechanisms relevant for energy balance homeostasis in health and disease. Because sensory innervation by dorsal root ganglia (DRG) neurons goes far beyond vagally innervated viscera and includes adipose tissue, skeletal muscle, and skin, it is in a position to provide much more complete metabolic information to the brain. Molecular and anatomical identification of function specific DRG neurons will be important steps in designing pharmacological and neuromodulation approaches to affect energy balance regulation in disease states such as obesity, diabetes, and cancer.
Collapse
Affiliation(s)
- Heike Münzberg
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA.
| | - Hans-Rudolf Berthoud
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA.
| | - Winfried L Neuhuber
- Institute for Anatomy and Cell Biology, Friedrich-Alexander University, Erlangen, Germany.
| |
Collapse
|
2
|
Leva TM, Whitmire CJ. Thermosensory thalamus: parallel processing across model organisms. Front Neurosci 2023; 17:1210949. [PMID: 37901427 PMCID: PMC10611468 DOI: 10.3389/fnins.2023.1210949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 09/15/2023] [Indexed: 10/31/2023] Open
Abstract
The thalamus acts as an interface between the periphery and the cortex, with nearly every sensory modality processing information in the thalamocortical circuit. Despite well-established thalamic nuclei for visual, auditory, and tactile modalities, the key thalamic nuclei responsible for innocuous thermosensation remains under debate. Thermosensory information is first transduced by thermoreceptors located in the skin and then processed in the spinal cord. Temperature information is then transmitted to the brain through multiple spinal projection pathways including the spinothalamic tract and the spinoparabrachial tract. While there are fundamental studies of thermal transduction via thermosensitive channels in primary sensory afferents, thermal representation in the spinal projection neurons, and encoding of temperature in the primary cortical targets, comparatively little is known about the intermediate stage of processing in the thalamus. Multiple thalamic nuclei have been implicated in thermal encoding, each with a corresponding cortical target, but without a consensus on the role of each pathway. Here, we review a combination of anatomy, physiology, and behavioral studies across multiple animal models to characterize the thalamic representation of temperature in two proposed thermosensory information streams.
Collapse
Affiliation(s)
- Tobias M. Leva
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Clarissa J. Whitmire
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| |
Collapse
|
3
|
Levichkina EV, Busygina II, Pigareva ML, Pigarev IN. The Mysterious Island: Insula and Its Dual Function in Sleep and Wakefulness. Front Syst Neurosci 2021; 14:592660. [PMID: 33643002 PMCID: PMC7904873 DOI: 10.3389/fnsys.2020.592660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/18/2020] [Indexed: 12/30/2022] Open
Abstract
In the recent sleep studies, it was shown that afferentation of many cortical areas switches during sleep to the interoceptive one. However, it was unclear whether the insular cortex, which is often considered as the main cortical visceral representation, maintains the same effective connectivity in both states of vigilance, or processes interoceptive information predominantly in one state. We investigated neuronal responses of the cat insular cortex to electrical stimulations of the intestinal wall delivered during wakefulness and natural sleep. Marked increase was observed in the number of insular neurons responding to this stimulation in sleep comparing to wakefulness, and enlarged amplitudes of evoked local field potentials were found as well. Moreover, most of the cells responding to intestinal stimulation in wakefulness never responded to identical stimuli during sleep and vice versa. It was also shown that applied low intensity intestinal stimulations had never compromised sleep quality. In addition, experiments with microstimulation of the insular cortex and recording of intestinal myoelectric activity demonstrated that effective insula-to-gut propagation also happened only during sleep. On the other hand, the same insular stimulations in wakefulness led to contractions of orofacial muscles. The evoked face movements gradually disappeared in the course of sleep development. These findings demonstrate that pattern of efficient afferent and efferent connections of the insular cortex changes with transition from wakefulness to sleep.
Collapse
Affiliation(s)
- Ekaterina V. Levichkina
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, Moscow, Russia
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Irina I. Busygina
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Marina L. Pigareva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Ivan N. Pigarev
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, Moscow, Russia
| |
Collapse
|
4
|
Abstract
Gastrointestinal (GI) pain - a form of visceral pain - is common in some disorders, such as irritable bowel syndrome, Crohn's disease and pancreatitis. However, identifying the cause of GI pain frequently represents a diagnostic challenge as the clinical presentation is often blurred by concomitant autonomic and somatic symptoms. In addition, GI pain can be nociceptive, neuropathic and associated with cancer, but in many cases multiple aetiologies coexist in an individual patient. Mechanisms of GI pain are complex and include both peripheral and central sensitization and the involvement of the autonomic nervous system, which has a role in generating the symptoms that frequently accompany pain. Treatment of GI pain depends on the precise type of pain and the primary disorder in the patient but can include, for example, pharmacological therapy, cognitive behavioural therapies, invasive surgical procedures, endoscopic procedures and lifestyle alterations. Owing to the major differences between organ involvement, disease mechanisms and individual factors, treatment always needs to be personalized and some data suggest that phenotyping and subsequent individual management of GI pain might be options in the future.
Collapse
|
5
|
Brierley SM, Hibberd TJ, Spencer NJ. Spinal Afferent Innervation of the Colon and Rectum. Front Cell Neurosci 2018; 12:467. [PMID: 30564102 PMCID: PMC6288476 DOI: 10.3389/fncel.2018.00467] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/16/2018] [Indexed: 12/12/2022] Open
Abstract
Despite their seemingly elementary roles, the colon and rectum undertake a variety of key processes to ensure our overall wellbeing. Such processes are coordinated by the transmission of sensory signals from the periphery to the central nervous system, allowing communication from the gut to the brain via the "gut-brain axis". These signals are transmitted from the peripheral terminals of extrinsic sensory nerve fibers, located within the wall of the colon or rectum, and via their axons within the spinal splanchnic and pelvic nerves to the spinal cord. Recent studies utilizing electrophysiological, anatomical and gene expression techniques indicate a surprisingly diverse set of distinct afferent subclasses, which innervate all layers of the colon and rectum. Combined these afferent sub-types allow the detection of luminal contents, low- and high-intensity stretch or contraction, in addition to the detection of inflammatory, immune, and microbial mediators. To add further complexity, the proportions of these afferents vary within splanchnic and pelvic pathways, whilst the density of the splanchnic and pelvic innervation also varies along the colon and rectum. In this review we traverse this complicated landscape to elucidate afferent function, structure, and nomenclature to provide insights into how the extrinsic sensory afferent innervation of the colon and rectum gives rise to physiological defecatory reflexes and sensations of discomfort, bloating, urgency, and pain.
Collapse
Affiliation(s)
- Stuart M Brierley
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide, Adelaide, SA, Australia
| | - Timothy J Hibberd
- Visceral Neurophysiology Laboratory, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - Nick J Spencer
- Visceral Neurophysiology Laboratory, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| |
Collapse
|
6
|
Hockley JRF, Smith ESJ, Bulmer DC. Human visceral nociception: findings from translational studies in human tissue. Am J Physiol Gastrointest Liver Physiol 2018; 315:G464-G472. [PMID: 29848022 DOI: 10.1152/ajpgi.00398.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Peripheral sensitization of nociceptors during disease has long been recognized as a leading cause of inflammatory pain. However, a growing body of data generated over the last decade has led to the increased understanding that peripheral sensitization is also an important mechanism driving abdominal pain in highly prevalent functional bowel disorders, in particular, irritable bowel syndrome (IBS). As such, the development of drugs that target pain-sensing nerves innervating the bowel has the potential to be a successful analgesic strategy for the treatment of abdominal pain in both organic and functional gastrointestinal diseases. Despite the success of recent peripherally restricted approaches for the treatment of IBS, not all drugs that have shown efficacy in animal models of visceral pain have reduced pain end points in clinical trials of IBS patients, suggesting innate differences in the mechanisms of pain processing between rodents and humans and, in particular, how we model disease states. To address this gap in our understanding of peripheral nociception from the viscera and the body in general, several groups have developed experimental systems to study nociception in isolated human tissue and neurons, the findings of which we discuss in this review. Studies of human tissue identify a repertoire of human primary afferent subtypes comparable to rodent models including a nociceptor population, the targeting of which will shape future analgesic development efforts. Detailed mechanistic studies in human sensory neurons combined with unbiased RNA-sequencing approaches have revealed fundamental differences in not only receptor/channel expression but also peripheral pain pathways.
Collapse
Affiliation(s)
- James R F Hockley
- Department of Pharmacology, University of Cambridge , Cambridge , United Kingdom
| | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge , Cambridge , United Kingdom
| | - David C Bulmer
- Department of Pharmacology, University of Cambridge , Cambridge , United Kingdom
| |
Collapse
|
7
|
Pigarev IN, Pigareva ML. Association of sleep impairments and gastrointestinal disorders in the context of the visceral theory of sleep. J Integr Neurosci 2018; 16:143-156. [PMID: 28891506 DOI: 10.3233/jin-170005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
It was noticed long ago that sleep disorders or interruptions to the normal sleep pattern were associated with various gastrointestinal disorders. We review the studies which established the causal link between these disorders and sleep impairment. However, the mechanism of interactions between the quality of sleep and gastrointestinal pathophysiology remained unclear. Recently, the visceral theory of sleep was formulated. This theory proposes that the same brain structures, and particularly the same cortical sensory areas, which in wakefulness are involved in processing of the exteroceptive information, switch during sleep to the processing of information coming from various visceral systems. We review the studies which demonstrated that neurons of the various cortical areas (occipital, parietal, frontal) during sleep began to fire in response to activation coming from the stomach and small intestine. These data demonstrate that, during sleep, the computational power of the central nervous system, including all cortical areas, is engaged in restoration of visceral systems. Thus, the general mechanism of the interaction between quality of sleep and health became clear.
Collapse
Affiliation(s)
- Ivan N Pigarev
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, Bol'shoy Karetniy st. 19, Moscow, 127994, Russia. E-mail:
| | - Marina L Pigareva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerova st. 5-a, Moscow, 117485, Russia. E-mail:
| |
Collapse
|
8
|
Lin SD, Tang T, Zhao TB, Liu SJ. Central projections and connections of lumbar primary afferent fibers in adult rats: effectively revealed using Texas red-dextran amine tracing. Neural Regen Res 2017; 12:1695-1702. [PMID: 29171435 PMCID: PMC5696851 DOI: 10.4103/1673-5374.217371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Signals from lumbar primary afferent fibers are important for modulating locomotion of the hind-limbs. However, silver impregnation techniques, autoradiography, wheat germ agglutinin-horseradish peroxidase and cholera toxin B subunit-horseradish peroxidase cannot image the central projections and connections of the dorsal root in detail. Thus, we injected 3-kDa Texas red-dextran amine into the proximal trunks of L4 dorsal roots in adult rats. Confocal microscopy results revealed that numerous labeled arborizations and varicosities extended to the dorsal horn from T12–S4, to Clarke's column from T10–L2, and to the ventral horn from L1–5. The labeled varicosities at the L4 cord level were very dense, particularly in laminae I–III, and the density decreased gradually in more rostral and caudal segments. In addition, they were predominately distributed in laminae I–IV, moderately in laminae V–VII and sparsely in laminae VIII–X. Furthermore, direct contacts of lumbar afferent fibers with propriospinal neurons were widespread in gray matter. In conclusion, the projection and connection patterns of L4 afferents were illustrated in detail by Texas red-dextran amine-dorsal root tracing.
Collapse
Affiliation(s)
- Shi-de Lin
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing; Department of Spinal Cord Injury, the General Hospital of Jinan Military Command, Jinan, Shandong Province, China
| | - Tao Tang
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Ting-Bao Zhao
- Department of Spinal Cord Injury, the General Hospital of Jinan Military Command, Jinan, Shandong Province, China
| | - Shao-Jun Liu
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| |
Collapse
|
9
|
Kanda H, Clodfelder-Miller BJ, Gu JG, Ness TJ, DeBerry JJ. Electrophysiological properties of lumbosacral primary afferent neurons innervating urothelial and non-urothelial layers of mouse urinary bladder. Brain Res 2016; 1648:81-89. [PMID: 27372884 DOI: 10.1016/j.brainres.2016.06.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 05/23/2016] [Accepted: 06/28/2016] [Indexed: 10/21/2022]
Abstract
Pelvic nerve (PN) bladder primary afferent neurons were retrogradely labeled by intraparenchymal (IPar) microinjection of fluorescent tracer or intravesical (IVes) infusion of tracer into the bladder lumen. IPar and IVes techniques labeled two distinct populations of PN bladder neurons differentiated on the basis of dorsal root ganglion (DRG) soma labeling, dye distribution within the bladder, and intrinsic electrophysiological properties. IPar (Fast blue)- and IVes (DiI)-labeled neurons accounted for 91.5% (378.3±32.3) and 8% (33.0±26.0) of all labeled neurons, respectively (p<0.01), with only 2.0±1.2 neurons labeled by both techniques. When dyes were switched, IPar (DiI)- and IVes (Fast blue) labeled neurons accounted for 77.6% (103.0±25.8) and 22.4% (29.8±10.5), respectively (P<0.05), with 6.0±1.5 double-labeled neurons. Following IPar labeling, DiI was distributed throughout non-urothelial layers of the bladder. In contrast, dye was contained within the urothelium and occasionally the submucosa after IVes labeling. Electrophysiological properties of DiI-labeled IPar and IVes DRG neurons were characterized by whole-mount, in situ patch-clamp recordings. IPar- and IVes-labeled neurons differed significantly with respect to rheobase, input resistance, membrane capacitance, amplitude of inactivating and sustained K(+) currents, and rebound action potential firing, suggesting that the IVes population is more excitable. This study is the first to demonstrate that IVes labeling is a minimally invasive approach for retrograde labeling of PN bladder afferent neurons, to selectively identify urothelial versus non-urothelial bladder DRG neurons, and to elucidate electrophysiological properties of urothelial and non-urothelial afferents in an intact DRG soma preparation.
Collapse
Affiliation(s)
- Hirosato Kanda
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Buffie J Clodfelder-Miller
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jianguo G Gu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Timothy J Ness
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jennifer J DeBerry
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
| |
Collapse
|
10
|
Schwartz ES, La JH, Young EE, Feng B, Joyce S, Gebhart GF. Chronic Prostatitis Induces Bladder Hypersensitivity and Sensitizes Bladder Afferents in the Mouse. J Urol 2016; 196:892-901. [PMID: 26997315 DOI: 10.1016/j.juro.2016.03.077] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2016] [Indexed: 12/30/2022]
Abstract
PURPOSE Chronic prostatitis/chronic pelvic pain syndrome causes symptoms that include the frequent and urgent need to urinate, pain or burning during urination and pain radiating to the back, abdomen and/or colorectum. These bladder symptoms suggest that chronic prostatitis/chronic pelvic pain syndrome is associated with sensitization of adjacent organs, termed cross-organ sensitization. The objective of this study was to determine the extent of 1) changes in immunomodulatory mediators in the prostate and bladder after inflammation of the prostate and 2) bladder function and bladder afferent sensitization. MATERIALS AND METHODS Prostate and bladder histology, immunohistochemistry and expression of immunomodulatory targets were examined weekly after zymosan or vehicle was injected in the dorsal lobe of the mouse prostate. Cystometry, bladder and bladder afferent sensitivity were also assessed weekly. RESULTS Prostate inflammation induced significant up-regulation in proinflammatory and anti-inflammatory cytokines TNF-α (tumor necrosis factor-α) and IL-10 (interleukin-10), growth factor NGF (nerve growth factor), and T-lymphocyte markers FoxP3, CD4 and CD8 in the prostate and the bladder. Notably, prostatitis significantly increased urinary voiding frequency, induced hypersensitivity to bladder distension and sensitized bladder afferents. We also examined sensory (afferent) co-innervation by injecting retrograde tracers DiI and Fast Blue in the bladder wall and the prostate, respectively. This showed that a significant proportion (approximately 17%) of dorsal root ganglion afferent somata contained tracers from the bladder and the prostate. CONCLUSIONS These observations support an afferent contribution to chronic prostatitis/chronic pelvic pain syndrome and cross-organ sensitization from prostate to bladder.
Collapse
Affiliation(s)
- Erica S Schwartz
- Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania.
| | - Jun-Ho La
- Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Erin E Young
- Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bin Feng
- Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Sonali Joyce
- Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - G F Gebhart
- Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|
11
|
Pigarev IN, Pigareva ML. The state of sleep and the current brain paradigm. Front Syst Neurosci 2015; 9:139. [PMID: 26528146 PMCID: PMC4602122 DOI: 10.3389/fnsys.2015.00139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/22/2015] [Indexed: 01/27/2023] Open
Abstract
Up to the present time cerebral cortex was considered as substrate for realization of the highest psychical functions including consciousness. Cortical sensory areas were regarded as structures specialized for processing of information coming from one particular modality (visual, auditory, somatosensory, and so on). However, studies of cortical activity in sleep-wake cycle demonstrated that during sleep the same neurons in the same cortical areas switch to processing of signals coming from the various visceral systems. After awakening these visceral responses disappear and the neurons return to processing of the information coming from the exteroreceptors. These observations indicate that most likely cortical areas are universal processors, which perform particular operations with incoming information independent of its origin. During wakefulness, results of the information processing on the cortical level should be directed to structures connected with organization of behavior and consciousness, while during sleep cortical outputs should be redirected to structures performing integration of the visceral information. Thus, results of sleep studies indicate that current brain paradigm should be changed.
Collapse
Affiliation(s)
- Ivan N. Pigarev
- Laboratory of Sensory Information Processing, Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of SciencesMoscow, Russia
| | - Marina L. Pigareva
- Laboratory of Neuroontogenesis, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of SciencesMoscow, Russia
| |
Collapse
|
12
|
Pigarev IN, Pigareva ML. Partial sleep in the context of augmentation of brain function. Front Syst Neurosci 2014; 8:75. [PMID: 24822040 PMCID: PMC4013465 DOI: 10.3389/fnsys.2014.00075] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/14/2014] [Indexed: 11/13/2022] Open
Abstract
Inability to solve complex problems or errors in decision making is often attributed to poor brain processing, and raises the issue of brain augmentation. Investigation of neuronal activity in the cerebral cortex in the sleep-wake cycle offers insights into the mechanisms underlying the reduction in mental abilities for complex problem solving. Some cortical areas may transit into a sleep state while an organism is still awake. Such local sleep would reduce behavioral ability in the tasks for which the sleeping areas are crucial. The studies of this phenomenon have indicated that local sleep develops in high order cortical areas. This is why complex problem solving is mostly affected by local sleep, and prevention of local sleep might be a potential way of augmentation of brain function. For this approach to brain augmentation not to entail negative consequences for the organism, it is necessary to understand the functional role of sleep. Our studies have given an unexpected answer to this question. It was shown that cortical areas that process signals from extero- and proprioreceptors during wakefulness, switch to the processing of interoceptive information during sleep. It became clear that during sleep all "computational power" of the brain is directed to the restoration of the vital functions of internal organs. These results explain the logic behind the initiation of total and local sleep. Indeed, a mismatch between the current parameters of any visceral system and the genetically determined normal range would provide the feeling of tiredness, or sleep pressure. If an environmental situation allows falling asleep, the organism would transit to a normal total sleep in all cortical areas. However, if it is impossible to go to sleep immediately, partial sleep may develop in some cortical areas in the still behaviorally awake organism. This local sleep may reduce both the "intellectual power" and the restorative function of sleep for visceral organs.
Collapse
Affiliation(s)
- Ivan N. Pigarev
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of SciencesMoscow, Russia
| | - Marina L. Pigareva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of SciencesMoscow, Russia
| |
Collapse
|
13
|
Pigarev IN, Bagaev VA, Levichkina EV, Fedorov GO, Busigina II. Cortical visual areas process intestinal information during slow-wave sleep. Neurogastroenterol Motil 2013; 25:268-75, e169. [PMID: 23216826 DOI: 10.1111/nmo.12052] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Previously we have shown that, during sleep, electrical and magnetic stimulation of areas of the stomach and small intestine evoked neuronal and EEG responses in various cortical areas. In this study we wanted to correlate natural myoelectrical activity of the duodenum with cortical neuronal activity, and to investigate whether there is a causal link between them during periods of slow-wave sleep. METHODS We have recorded the myoelectrical activity from the wall of the duodenum and activity of single neurons from three cortical visual areas in naturally sleeping cats and investigated causal interrelationship between these structures during slow-wave sleep. KEY RESULTS About 30% of the cortical neurons studied changed their firing rate dependent on the phases of the peristaltic cycle and demonstrated selectivity to particular pattern of duodenal myoelectrical activity during slow-wave sleep. This interrelationship was never seen when awake. CONCLUSIONS & INFERENCES This observation supports the hypothesis that, during sleep, the cerebral cortex switches from processing of exteroceptive and proprioceptive information to processing of interoceptive information.
Collapse
Affiliation(s)
- I N Pigarev
- Institute for Problems of Information Transmission (Kharkevich Institute), Russian Academy of Sciences, Moscow, Russia.
| | | | | | | | | |
Collapse
|
14
|
Target-dependence of sensory neurons: An ultrastructural comparison of axotomised dorsal root ganglion neurons with allowed or denied reinnervation of peripheral targets. Neuroscience 2013; 228:163-78. [DOI: 10.1016/j.neuroscience.2012.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 09/01/2012] [Accepted: 10/05/2012] [Indexed: 12/21/2022]
|
15
|
Zimmerman AL, Sawchuk M, Hochman S. Monoaminergic modulation of spinal viscero-sympathetic function in the neonatal mouse thoracic spinal cord. PLoS One 2012; 7:e47213. [PMID: 23144807 PMCID: PMC3489886 DOI: 10.1371/journal.pone.0047213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 09/10/2012] [Indexed: 11/27/2022] Open
Abstract
Descending serotonergic, noradrenergic, and dopaminergic systems project diffusely to sensory, motor and autonomic spinal cord regions. Using neonatal mice, this study examined monoaminergic modulation of visceral sensory input and sympathetic preganglionic output. Whole-cell recordings from sympathetic preganglionic neurons (SPNs) in spinal cord slice demonstrated that serotonin, noradrenaline, and dopamine modulated SPN excitability. Serotonin depolarized all, while noradrenaline and dopamine depolarized most SPNs. Serotonin and noradrenaline also increased SPN current-evoked firing frequency, while both increases and decreases were seen with dopamine. In an in vitro thoracolumbar spinal cord/sympathetic chain preparation, stimulation of splanchnic nerve visceral afferents evoked reflexes and subthreshold population synaptic potentials in thoracic ventral roots that were dose-dependently depressed by the monoamines. Visceral afferent stimulation also evoked bicuculline-sensitive dorsal root potentials thought to reflect presynaptic inhibition via primary afferent depolarization. These dorsal root potentials were likewise dose-dependently depressed by the monoamines. Concomitant monoaminergic depression of population afferent synaptic transmission recorded as dorsal horn field potentials was also seen. Collectively, serotonin, norepinephrine and dopamine were shown to exert broad and comparable modulatory regulation of viscero-sympathetic function. The general facilitation of SPN efferent excitability with simultaneous depression of visceral afferent-evoked motor output suggests that descending monoaminergic systems reconfigure spinal cord autonomic function away from visceral sensory influence. Coincident monoaminergic reductions in dorsal horn responses support a multifaceted modulatory shift in the encoding of spinal visceral afferent activity. Similar monoamine-induced changes have been observed for somatic sensorimotor function, suggesting an integrative modulatory response on spinal autonomic and somatic function.
Collapse
Affiliation(s)
- Amanda L. Zimmerman
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Michael Sawchuk
- Department of Physiology, Emory University, Atlanta, Georgia, United States of America
| | - Shawn Hochman
- Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, Georgia, United States of America
- Department of Physiology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
16
|
Interscalene brachial plexus block for scapular and upper chest pain due to cervical radiculopathy: a randomized controlled clinical trial. J Orthop Sci 2012; 17:515-20. [PMID: 22828914 DOI: 10.1007/s00776-012-0248-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 05/15/2012] [Indexed: 02/09/2023]
Abstract
BACKGROUND Animal experiments have shown that one of the pathways for pain originating from the cervical spine is the sympathetic trunk. However, there have been few reports regarding the cervical pain pathway and efficacy of interscalene brachial plexus block for upper limb, scapular and chest pain originating in the cervical spine in clinical cases. The purpose of the present study was to clarify the efficacy of interscalene brachial plexus block for upper limb, scapular and chest pain. METHODS Patients (137 men and 223 women) who had cervical radicular pain were studied. The intensity of upper limb, scapular and chest pain was measured by using a VAS before injection and at 5 min and 7 days after injection. To evaluate the efficacy of interscalene brachial plexus block, patients with cervical radicular pain who had received NSAIDs for at least 2 weeks were randomized to interscalene brachial plexus block or control block groups. VAS scores were compared to assess the effects of injection and the pain pathway. RESULTS The average VAS score for upper limb pain with or without scapular and chest pain was significantly reduced by interscalene brachial plexus block compared with control block at 5 min and 7 days after injection. After interscalene brachial plexus block, 89 patients reported symptoms of stellate ganglion block versus no patients after control block. Scapular and chest pain was significantly reduced in the patients with stellate ganglion block compared to those without stellate ganglion block. CONCLUSIONS Interscalene brachial plexus block is useful for upper limb, scapular and chest pain due to disorders of the cervical spine. The scapular and chest pain pathway is more likely to be interrupted by an interscalene brachial plexus block that causes a stellate ganglion block compared to an interscalene brachial plexus block without stellate ganglion block.
Collapse
|
17
|
Frøkjær JB, Olesen SS, Graversen C, Andresen T, Lelic D, Drewes AM. Neuroimaging of the human visceral pain system–A methodological review. Scand J Pain 2011; 2:95-104. [DOI: 10.1016/j.sjpain.2011.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 02/25/2011] [Indexed: 12/13/2022]
Abstract
Abstract
During the last decades there has been a tremendous development of non-invasive methods for assessment of brain activity following visceral pain. Improved methods for neurophysiological and brain imaging techniques have vastly increased our understanding of the central processing of gastrointestinal sensation and pain in both healthy volunteers as well as in patients suffering from gastrointestinal disorders. The techniques used are functional magnetic resonance imaging (fMRI), positron emission tomography (PET), electroencephalography (EEG)/evoked brain potentials (EPs), magnetoencephalography (MEG), single photon emission computed tomography (SPECT), and the multimodal combinations of these techniques. The use of these techniques has brought new insight into the complex brain processes underlying pain perception, including a number of subcortical and cortical regions, and paved new ways in our understanding of acute and chronic pain. The pathways are dynamic with a delicate balance between facilitatory and inhibitory pain mechanisms, and with modulation of the response to internal or external stressors with a high degree of plasticity. Hence, the ultimate goal in imaging of pain is to follow the stimulus response throughout the neuraxis.
Brain activity measured by fMRI is based on subtracting regional changes in blood oxygenation during a resting condition from the signal during a stimulus condition, and has high spatial resolution but low temporal resolution. SPECT and PET are nuclear imaging techniques where radiolabeled molecules are injected with visualization of the distribution, density and activity of receptors in the brain allowing not only assessment of brain activity but also study of receptor sites. EEG is based on assessment of electrical activity in the brain, and recordings of the resting EEG and evoked potentials following an external stimulus are used to study normal visceral pain processing, alterations of pain processing in different patient groups and the effect of pharmacological intervention. EEG has high temporal resolution, but relative poor spatial resolution, which however to some extent can be overcome by applying inverse modelling algorithms and signal decomposition procedures. MEG is based on recording the magnetic fields produced by electrical currents in the brain, has high spatial resolution and is especially suitable for the study cortical activation.
The treatment of chronic abdominal pain is often ineffective and dissapointing, which leads to search for optimized treatment achieved on the basis of a better understanding of underlying pain mechanisms. Application of the recent improvements in neuroimaging on the visceral pain system may likely in near future contribute substantially to our understanding of the functional and structural pathophysiology underlying chronic visceral pain disorders, and pave the road for optimized individual and mechanism based treatments.
The purpose of this review is to give a state-of-the-art overview of these methods, with focus on EEG, and especially the advantages and limitations of the single methods in clinical gastrointestinal pain esearch including examples from relevant studies.
Collapse
Affiliation(s)
- Jens Brøndum Frøkjær
- Mech-Sense , Department of Gastroenterology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
- Department of Radiology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
| | - Søren Schou Olesen
- Mech-Sense , Department of Gastroenterology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
| | - Carina Graversen
- Mech-Sense , Department of Gastroenterology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
| | - Trine Andresen
- Mech-Sense , Department of Gastroenterology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
| | - Dina Lelic
- Mech-Sense , Department of Gastroenterology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
| | - Asbjørn Mohr Drewes
- Mech-Sense , Department of Gastroenterology , Aalborg Hospital , Aarhus University Hospital , Aalborg , Denmark
| |
Collapse
|
18
|
|
19
|
Abstract
AbstractThe peripheral nervous system (PNS) has classically been separated into a somatic division composed of both afferent and efferent pathways and an autonomic division containing only efferents. J. N. Langley, who codified this asymmetrical plan at the beginning of the twentieth century, considered different afferents, including visceral ones, as candidates for inclusion in his concept of the “autonomic nervous system” (ANS), but he finally excluded all candidates for lack of any distinguishing histological markers. Langley's classification has been enormously influential in shaping modern ideas about both the structure and the function of the PNS. We survey recent information about the PNS and argue that many of the sensory neurons designated as “visceral” and “somatic” are in fact part of a histologically distinct group of afferents concerned primarily autonomic function. These afferents have traditionally been known as “small dark” neurons or B-neurons. In this target article we outline an association between autonomic and B-neurons based on ontogeny, cell phenotype, and functional relations, grouping them together as part of a common reflex system involved in homeostasis. This more parsimonious classification of the PNS, made possible by the identification of a group of afferents associated primarily with the ANS, avoids a number of confusions produced by the classical orientation. It may also have practical implications for an understanding of nociception, homeostatic reflexes, and the evolution of the nervous system.
Collapse
|
20
|
|
21
|
|
22
|
Capsaicin-sensitive chemoceptive B-afferents: A neural system with dual sensory-efferent function. Behav Brain Sci 2011. [DOI: 10.1017/s0140525x00078924] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
23
|
|
24
|
|
25
|
|
26
|
Capsaicin-sensitivity and the sensory vagus: Do these exceptions prove or disprove the B-neuron rule for autonomic afferents? Behav Brain Sci 2011. [DOI: 10.1017/s0140525x00078912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
27
|
Russo D, Bombardi C, Grandis A, Furness JB, Spadari A, Bernardini C, Chiocchetti R. Sympathetic innervation of the ileocecal junction in horses. J Comp Neurol 2010; 518:4046-66. [PMID: 20737599 DOI: 10.1002/cne.22443] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The distribution and chemical phenotypes of sympathetic and dorsal root ganglion (DRG) neurons innervating the equine ileocecal junction (ICJ) were studied by combining retrograde tracing and immunohistochemistry. Immunoreactivity (IR) for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), neuronal nitric oxide synthase (nNOS), calcitonin gene-related peptide (CGRP), substance P (SP), and neuropeptide Y (NPY) was investigated. Sympathetic neurons projecting to the ICJ were distributed within the celiac (CG), cranial mesenteric (CranMG), and caudal mesenteric (CaudMG) ganglia, as well as in the last ganglia of the thoracic sympathetic chain and in the splanchnic ganglia. In the CG and CranMG 91 +/- 8% and 93 +/- 12% of the neurons innervating the ICJ expressed TH- and DBH-IR, respectively. In the CaudMG 90 +/- 15% and 94 +/- 5% of ICJ innervating neurons were TH- and DBH-IR, respectively. Sympathetic (TH-IR) fibers innervated the myenteric and submucosal ganglia, ileal blood vessels, and the muscle layers. They were more concentrated at the ICJ level and were also seen encircling myenteric plexus (MP) and submucosal plexus (SMP) descending neurons that were retrogradely labeled from the ICJ. Among the few retrogradely labeled DRG neurons, nNOS-, CGRP-, and SP-IR nerve cells were observed. Dense networks of CGRP-, nNOS-, and SP-IR varicosities were seen around retrogradely labeled prevertebral ganglia neurons. The CGRP-IR fibers are probably the endings of neurons projecting from the intestine to the prevertebral ganglia. These findings indicate that this crucial region of the intestinal tract is strongly influenced by the sympathetic system and that sensory information of visceral origin influences the sympathetic control of the ICJ.
Collapse
Affiliation(s)
- D Russo
- Department of Veterinary Morphophysiology and Animal Productions (UNI EN ISO 9001:2008), University of Bologna, 40064 Ozzano Emilia, Bologna, Italy
| | | | | | | | | | | | | |
Collapse
|
28
|
Mekhail NA, Cheng J, Narouze S, Kapural L, Mekhail MN, Deer T. Clinical Applications of Neurostimulation: Forty Years Later. Pain Pract 2010; 10:103-12. [DOI: 10.1111/j.1533-2500.2009.00341.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
29
|
Clinical study of low back pain and radicular pain pathways by using l2 spinal nerve root infiltration: a randomized, controlled, clinical trial. Spine (Phila Pa 1976) 2009; 34:2008-13. [PMID: 19730208 DOI: 10.1097/brs.0b013e3181b1fb96] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Randomized control trial (RCT) for L2 spinal nerve infiltration (L2 block) in clinical cases. OBJECTIVES To confirm or refute the effect of L2 block using RCT, and to study the pathway of low back pain (LBP) and radicular pain in clinical cases. SUMMARY OF BACKGROUND DATA It has been reported in animal experiments that one of the main pathways of pain originating from the lumbar spine is the sympathetic trunk through the L2 spinal nerve rootvia sympathetic afferents. METHODS To evaluate the effectiveness of L2 block, patients who had LBP and were treated with nonsteroidal anti-inflammatory drugs for at least 2 weeks were then randomized to the L2 block or control block groups. The intensities of LBP and radicular pain were measured using visual analog scale and face scale before and at 5 minutes and 7 days after the injection. These values were compared, and the effects of the injections on the pain pathway were studied. RESULTS The average visual analog scale scores for LBP before and at 5 minutes and 7 days after the injection were 69, 14, and 44 mm in the L2 block group and 68, 62, and 59 mm in the control block group, respectively. After L2 block, 28 patients reported adequate therapeutic effect at 10 weeks, and the effect lasted for more than 24 weeks in 10 of these patients. After control block, 9 patients reported adequate therapeutic effect at 10 and 24 weeks. CONCLUSION The LBP and radicular pain pathways were likely interrupted by L2 block. An L2 block is useful in reducing LBP due to the disorders of L2 spinal nerve-innervated structures, such as the disc, facet joint, and sacroiliac joint. However, the therapeutic value of an L2 block may be occasionally insufficient to alleviate pain completely because of the short duration of its' effect.
Collapse
|
30
|
Li J, Micevych P, McDonald J, Rapkin A, Chaban V. Inflammation in the uterus induces phosphorylated extracellular signal-regulated kinase and substance P immunoreactivity in dorsal root ganglia neurons innervating both uterus and colon in rats. J Neurosci Res 2009; 86:2746-52. [PMID: 18478547 DOI: 10.1002/jnr.21714] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In women, clinical studies suggest that pain syndromes such as irritable bowel syndrome and interstitial cystitis, which are associated with visceral hyperalgesia, are often comorbid with endometriosis and chronic pelvic pain. One of the possible explanations for this phenomenon is viscerovisceral cross-sensitization, in which increased nociceptive input from an inflamed pelvic organ sensitizes neurons that receive convergent input to the same dorsal root ganglion (DRG) from an unaffected visceral organ. Nociception induces up-regulation of cellular mechanisms such as phosphorylated extracellular signal-regulated kinase (pERK) and substance P (SP), neurotransmitters associated with induced pain sensation. The purpose of this study was to determine, in a rodent model, whether uterine inflammation increased the number of pERK- and SP-positive neurons that received input from both the uterus and the colon. Cell bodies of colonic and uterine DRG were retrogradely labeled with fluorescent tracer dyes microinjected into the colon/rectum and into the uterus. Ganglia were harvested for fluorescent microscopy to identify positively stained neurons. Approximately 6% of neurons were colon specific and 10% uterus specific. Among these uterus- or colon-specific neurons, up to 3-5% of DRG neurons in the lumbosacral neurons (L1-S3 levels) received input from both visceral organs. Uterine inflammation increased the number of pERK- and SP-immunoreactive DRG neurons innervating specifically colon, or innervating specifically uterus, and those innervating both organs. These results suggest that a localized inflammation activates primary visceral afferents, regardless of whether they innervate the affected organ. This visceral sensory integration in the DRG may underlie the observed comorbidity of female pelvic pain syndromes.
Collapse
Affiliation(s)
- Jichang Li
- Department of Anesthesiology, Harbor-UCLA Medical Center, Los Angeles, California, USA
| | | | | | | | | |
Collapse
|
31
|
Robinson DR, Gebhart GF. Inside information: the unique features of visceral sensation. Mol Interv 2009; 8:242-53. [PMID: 19015388 DOI: 10.1124/mi.8.5.9] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Most of what is written and believed about pain and nociceptors originates from studies of the "somatic" (non-visceral) sensory system. As a result, the unique features of visceral pain are often overlooked. In the clinic, the management of visceral pain is typically poor, and drugs that are used with some efficacy to treat somatic pain often present unwanted effects on the viscera. For these reasons, a better understanding of visceral sensory neurons-particularly visceral nociceptors-is required. This review provides evidence of functional, morphological, and biochemical differences between visceral and non-visceral afferents, with a focus on potential nociceptive roles, and also considers some of the potential mechanisms of visceral mechanosensation.
Collapse
Affiliation(s)
- David R Robinson
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | | |
Collapse
|
32
|
Abstract
Functional gastrointestinal disorders are commonly encountered in clinical practice, and pain is their commonest presenting symptom. In addition, patients with these disorders often demonstrate a heightened sensitivity to experimental visceral stimulation, termed visceral pain hypersensitivity that is likely to be important in their pathophysiology. Knowledge of how the brain processes sensory information from visceral structures is still in its infancy. However, our understanding has been propelled by technological imaging advances such as functional Magnetic Resonance Imaging, Positron Emission Tomography, Magnetoencephalography, and Electroencephalography (EEG). Numerous human studies have non-invasively demonstrated the complexity involved in functional pain processing, and highlighted a number of subcortical and cortical regions involved. This review will focus on the neurophysiological pathways (primary afferents, spinal and supraspinal transmission), brain-imaging techniques and the influence of endogenous and psychological processes in healthy controls and patients suffering from functional gastrointestinal disorders. Special attention will be paid to the newer EEG source analysis techniques. Understanding the phenotypic differences that determine an individual’s response to injurious stimuli could be the key to understanding why some patients develop pain and hyperalgesia in response to inflammation/injury while others do not. For future studies, an integrated approach is required incorporating an individual’s psychological, autonomic, neuroendocrine, neurophysiological, and genetic profile to define phenotypic traits that may be at greater risk of developing sensitised states in response to gut inflammation or injury.
Collapse
|
33
|
Park TJ, Comer C, Carol A, Lu Y, Hong HS, Rice FL. Somatosensory organization and behavior in naked mole-rats: II. Peripheral structures, innervation, and selective lack of neuropeptides associated with thermoregulation and pain. J Comp Neurol 2003; 465:104-20. [PMID: 12926019 DOI: 10.1002/cne.10824] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
African naked mole-rats are subterranean rodents that have a robust orienting response to stimulation of unique vibrissa-like body hairs that are widely spaced over an otherwise hairless skin. To determine whether these large body hairs have a specialized organization similar to facial vibrissae, the structure and innervation of facial vibrissa follicles, body hair follicles, and intervening skin in naked mole-rats was compared with that in rats and a furred African mole-rat species (the common mole-rat). Immunofluorescence and lectin-binding analyses revealed that the body hair follicles in naked mole-rats were exceptionally large and well innervated, similar to guard hairs of furred species. However, these body vibrissae lacked the anatomic specializations and unique types of innervation affiliated with follicle sinus complexes of facial vibrissae. In contrast to the furred species, naked mole-rats had a paucity of Abeta-fiber Merkel endings at all peripheral locations. Naked mole-rats also were completely lacking in cutaneous C-fibers immunoreactive for substance P and calcitonin gene-related peptide. In contrast, the hairless skin of the naked mole-rats had an exceptional abundance of presumptive Adelta-fibers. The unusual features of the cutaneous innervation in naked mole-rats are presumably adaptations to their subterranean environment and that they are the only known poikilothermic mammal. The features of this mammalian model system provide unique opportunities to discriminate mechanisms related to tactile spatial orientation, vascular regulation, and nociception.
Collapse
Affiliation(s)
- Thomas J Park
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
| | | | | | | | | | | |
Collapse
|
34
|
Nakano M, Kishida R, Funakoshi K, Tsukagoshi M, Goris RC, Kadota T, Atobe Y, Hisajima T. Central projections of thoracic splanchnic and somatic nerves and the location of sympathetic preganglionic neurons in Xenopus laevis. J Comp Neurol 2003; 456:321-37. [PMID: 12532405 DOI: 10.1002/cne.10514] [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: 12/17/2022]
Abstract
The central and peripheral organization of thoracic visceral and somatic nervous elements was studied by applying dextran amines to the proximal cut ends of the thoracic splanchnic and somatic nerves in Xenopus laevis. Many labeled dorsal root ganglion cells of visceral afferents, and all somatic afferents, were located in a single ganglion of one spinal segment, and the two types of cells were distributed topographically within the ganglion. The labeled sympathetic preganglionic neurons were located predominantly in the same area of the thoracic spinal gray as in other frogs and in mammals. The labeled visceral afferents projected to Lissauer's tract and the dorsal funiculus. The visceral fibers of the tract ascended to the level of the subcerebellar area, supplying collateral branches to the lateral one-third of the dorsal horn and to the area of brainstem nuclei, including lateral cervical and descending trigeminal nucleus, and descended to the filum terminale. The visceral fibers of the dorsal funiculus were distributed to the dorsal column nucleus and the solitary tract. A similar longitudinal projection was also seen in the somatic afferents. The dual central pathway of thoracic primary afferents in the anuran spinal cord is a property held in common with mammals, but the widespread rostrocaudal projection through Lissauer's tract may be a characteristic of the anuran central nervous system. In frogs, the direct transmission of primary afferent information to an extremely wide area of the central nervous system may be important for prompt assessment of environmental factors and control of body functions.
Collapse
Affiliation(s)
- Masato Nakano
- Department of System Neuroanatomy, Yokohama City University School of Medicine, Yokohama, 236-0004 Japan.
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Rola R, Szulczyk PJ, Witkowski G. Voltage-dependent Ca2+ currents in rat cardiac dorsal root ganglion neurons. Brain Res 2003; 961:171-8. [PMID: 12535791 DOI: 10.1016/s0006-8993(02)03950-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study presents the kinetic and pharmacological properties of voltage-gated Ca(2+) currents in anatomically defined cardiac dorsal root ganglion (DRG) neurons in rats. The neurons were labelled by prior injection of fluorescent tracer Fast Blue into the pericardial sack. There were three distinct groups of neurons with respect to cell size: small (27% of total; cell capacitance <30 pF), medium (65% of total; capacitance 30-80 pF) and large neurons (8% of total; capacitance >80 pF). The properties of Ca(2+) currents were tested in small and medium-sized neurons. In large neurons currents could not be adequately controlled and were not analysed. Ca(2+) currents did not completely inactivate during 100 ms depolarising voltage steps. The activation thresholds in small (-36.9+/-1.3 mV) and medium (-39.0+/-1.3 mV) size neurons were similar. Current densities were 105.8 pA/pF in small and 97.4 pA/pF in large neurons and also did not differ. The kinetic properties of activation and inactivation did not differ between small and medium-sized cardiac DRG neurons. At membrane potentials between -50 and -60 mV (the expected resting membrane potential in these neurons) 55 to 70% of Ca(2+) currents in small and medium-sized neurons were available for activation. Both, small and medium-sized neurons expressed similar proportions of L (7.5%), N (25%) and P/Q (36%) type Ca(2+) currents. We conclude that small and medium-sized cardiac DRG neurons are homogeneous with respect to the expression and properties of voltage-gated Ca(2+) currents. Voltage-gated Ca(2+) currents probably play an important role in action potential generation in cardiac DRG neurons due to their availability for activation at resting membrane potential, their high density and voltage threshold close to the threshold for voltage-gated Na(+) currents.
Collapse
Affiliation(s)
- Rafal Rola
- The Medical University of Warsaw, The Faculty of Medicine, Department of Experimental and Clinical Physiology, Krakowskie Przedmieście 26/28, Warsaw 00-927, Poland
| | | | | |
Collapse
|
36
|
Rola R, Szulczyk B, Szulczyk P, Witkowski G. Expression and kinetic properties of Na(+) currents in rat cardiac dorsal root ganglion neurons. Brain Res 2002; 947:67-77. [PMID: 12144854 DOI: 10.1016/s0006-8993(02)02908-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The expression and properties of voltage-gated Na(+) currents in cardiac dorsal root ganglion (DRG) neurons were assessed in this study. Cardiac DRG neurons were labelled by injecting the Fast Blue fluorescent tracer into the pericardium. Recordings were performed from 138 cells. Voltage-dependent Na(+) currents were found in 115 neurons. There were 109 neurons in which both tetrodotoxin-sensitive (TTX-S, blocked by 1 microM of TTX) and tetrodotoxin-resistant (TTX-R, insensitive to 1 microM of TTX) Na(+) currents were present. Five cells expressed TTX-R current only and one cell only the TTX-S current. The kinetic properties of Na(+) currents and action potential waveform parameters were measured in neurons with cell membrane capacitance ranging from 15 to 75 pF. The densities of TTX-R (110.0 pA/pF) and TTX-S (126.1 pA/pF) currents were not significantly different. Current threshold was significantly higher for TTX-R (-34 mV) than for TTX-S (-40.4 mV) currents. V(1/2) of activation for TTX-S current (-19.6 mV) was significantly more negative than for TTX-R current (-9.2 mV), but k factors did not differ significantly. V(1/2) and the k constant for inactivation for TTX-S currents were -35.6 and -5.7 mV, respectively. These values were significantly lower than those recorded for TTX-R current for which V(1/2) and k were -62.3 and -7.7 mV, respectively. The action potential threshold was lower, the 10-90% rise time and potential width were shorter before than after the application of TTX. Based on this we drew the conclusion that action potential recorded before adding tetrodotoxin was mainly TTX-S current dependent, while the action potential recorded after the application of toxin was TTX-R current dependent. We also found 23 cells with mean membrane capacitance ranging from 12 to 35 pF (the smallest labelled DRG cells found in this study) that did not express the Na(+) current. The function of these cells is unclear. We conclude that the overwhelming majority of cardiac dorsal root ganglion neurons in which voltage-dependent Na(+) currents were present, exhibited both TTX-S and TTX-R Na(+) currents with remarkably similar expression and kinetic properties.
Collapse
Affiliation(s)
- Rafał Rola
- Department of Experimental and Clinical Physiology, Faculty of Medicine, Medical University of Warsaw, Krakowskie Przedmieście 26/28, Warsaw 00-927, Poland
| | | | | | | |
Collapse
|
37
|
Abstract
The use of functional brain imaging techniques has led to considerable advances in our understanding of brain processing of human visceral sensation. The use of complementary techniques such as functional MRI, positron emission tomography, magnetoencephalography, and EEG has led to the identification of a network of brain areas that process visceral sensation. These studies suggest that unlike somatic sensation, which has an intense homuncular representation in the primary somatosensory cortex (SI), visceral sensation is primarily represented in the secondary somatosensory cortex, whereas representation in SI is vague. This difference could account for the poor localization of visceral sensation in comparison with somatic sensation. However, in a manner similar to that of somatic sensation, visceral sensation is represented in the paralimbic and limbic structures such as the insular, anterior cingulate, and prefrontal cortices. These areas are likely to mediate the affective and cognitive components of visceral sensation. Recent studies suggest that negative emotional factors such as fear, and cognitive factors such as attention can modulate the brain processing of visceral sensation in the insular and anterior cingulate cortices. In addition, alterations in the pattern of cortical processing of visceral sensation have been described in patients with functional gastrointestinal pain. It is likely that future research into the factors that modulate the brain processing of visceral sensation in health and disease are likely to improve further our understanding of the pathophysiology of functional visceral pain disorders.
Collapse
Affiliation(s)
- Q Aziz
- Department of Gastrointestinal Science, University of Manchester, UK.
| | | | | |
Collapse
|
38
|
Yuan Y, Chandler MJ, Foreman RD, Farber JP. Effects of abdominal or cardiopulmonary sympathetic afferents on upper cervical inspiratory neurons. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1289-95. [PMID: 10801299 DOI: 10.1152/ajpregu.2000.278.5.r1289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Responses of upper cervical inspiratory neurons (UCINs) to abdominal visceral or cardiopulmonary sympathetic stimulation were studied using extracellular recordings from 213 UCINs in 54 pentobarbital sodium-anesthetized and paralyzed rats. Phrenic nerve activity was used to assess inspiration. The UCINs discharging during inspiration only were mainly in the C(1) segment, whereas phase-spanning UCINs were mostly in the C(2) segment. Phase-spanning activity was typically retained after overventilation or vagotomy. When greater splanchnic nerve (GSN) or cardiopulmonary sympathetic afferent (CPSA) fibers were electrically stimulated, augmented UCIN activity was observed in 65% of cells responding to CPSA stimulation but in only 17% of cells responding to GSN. Response latencies were 10.7 +/- 0.5 and 20.6 +/- 1.5 (SE) ms, respectively. Many augmented responses to CPSA stimulation (64%) and all augmented responses to GSN stimulation were followed by suppression of UCIN discharge (biphasic response). Phrenic nerve activity was suppressed by both GSN and CPSA stimulation, but with shorter latency for the latter (29 +/- 0.7 vs. 14.0 +/- 0.7 ms). Excitation of UCINs using CPSA stimulation occurs more often and by a more direct pathway than for GSN input.
Collapse
Affiliation(s)
- Y Yuan
- Department of Physiology, Univeristy of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73190, USA
| | | | | | | |
Collapse
|
39
|
|
40
|
Hara K, Saito Y, Kirihara Y, Sakura S, Kosaka Y. Antinociceptive effects of intrathecal L-type calcium channel blockers on visceral and somatic stimuli in the rat. Anesth Analg 1998; 87:382-7. [PMID: 9706935 DOI: 10.1097/00000539-199808000-00027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED L-type calcium channels can modulate neuronal transduction in the spinal cord. However, their role in noxious information processing in animals that are physiologically intact has not been elucidated. We evaluated the effects of L-type calcium channel blockers diltiazem and verapamil on somatic and visceral nociception at the level of the spinal cord. Intrathecal catheters were inserted at the L4-5 level in Sprague-Dawley rats. The tail flick (TF) test and colorectal distension (CD) test were used to assess somatic and visceral antinociceptive effects, respectively. Motor function was assessed by posture and muscle tone in the limbs. TF latency and CD threshold were measured before and for 180 min after the intrathecal administration of verapamil (50, 100, 300, and 500 microg), diltiazem (100, 300, 500, and 1000 microg), or isotonic sodium chloride solution. The percent maximal possible effect (%MPE) was calculated by transforming response threshold in TF and CD tests. Intrathecally administered diltiazem or verapamil increased both TF latency and CD threshold in a dose-dependent fashion. Isotonic sodium chloride solution, diltiazem 100 microg, and verapamil 50 microg did not increase %MPE in either test. Diltiazem 300 or 500 microg or verapamil 300 or 500 microg significantly (P < 0.05) increased %MPE, with the peak effects 5 min after administration and short-duration antinociception. %MPE was 100% until 15 min after the administration of diltiazem 1000 microg, and significant antinociception continued until 180 min in the TF test. Motor paralysis was observed after the administration of the larger dose of each drug. We demonstrated that intrathecally administered L-type calcium channel blockers diltiazem or verapamil produced both somatic and visceral antinociception and motor block dose-dependently. IMPLICATIONS We examined the effects of intrathecally administered L-type calcium channel blockers diltiazem and verapamil on somatic and visceral nociception in rats. L-type calcium channel blockers produced antinociceptive effects, suggesting a possible clinical application to control pain.
Collapse
Affiliation(s)
- K Hara
- Department of Anesthesiology, Shimane Medical University, Izumo, Japan
| | | | | | | | | |
Collapse
|
41
|
Hara K, Saito Y, Kirihara Y, Sakura S, Kosaka Y. Antinociceptive Effects of Intrathecal L-Type Calcium Channel Blockers on Visceral and Somatic Stimuli in the Rat. Anesth Analg 1998. [DOI: 10.1213/00000539-199808000-00027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
42
|
Affiliation(s)
- Q Aziz
- Department of Medicine, Section of Gastroenterology, University of Manchester, England
| | | |
Collapse
|
43
|
Burton MB, Gebhart GF. Effects of intracolonic acetic acid on responses to colorectal distension in the rat. Brain Res 1995; 672:77-82. [PMID: 7749755 DOI: 10.1016/0006-8993(94)01382-r] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The present study was undertaken to examine the effects of chemical irritation of the colon on responses to noxious colorectal distension (CRD) in the rat. Pressor and abdominal visceromotor (electromyographic, EMG) responses to CRD were examined in chronically instrumented, unanesthetized rats before and at 6 and 24 h after intracolonic instillation of 5% acetic acid (HAc) or saline. The magnitude of the visceromotor response to phasic CRD (80 mmHg, 20 s) was significantly greater in HAc- than in saline-treated rats at both 6 and 24 h. This was accompanied by a significant increase in the resting EMG activity in both groups, but not between groups. There was, however, no change produced in either the resting mean arterial pressure (MAP) or the magnitude of the pressor response to CRD by HAc treatment. Signs of colonic inflammation (leukocyte infiltration) were examined periodically after HAc treatment, but were apparent only at 24 h. It is concluded that mechanical (distension) and chemical irritation (HAc) of the colon can elicit changes in the basal visceromotor activity and the visceromotor response to CRD. These changes seem to reflect an alteration in the sensitivity of the colon to noxious stimuli.
Collapse
Affiliation(s)
- M B Burton
- Department of Pharmacology, University of Iowa, Iowa City 52242, USA
| | | |
Collapse
|
44
|
Speakman CT, Kamm MA, Swash M. Rectal sensory evoked potentials: an assessment of their clinical value. Int J Colorectal Dis 1993; 8:23-8. [PMID: 8492039 DOI: 10.1007/bf00341272] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To assess abnormalities of sensory conduction in anorectal disease we have evaluated peripheral sensory perception and somatosensory evoked potentials produced by rectal stimulation in control subjects and patients with either constipation or idiopathic faecal incontinence. Evoked potentials were also recorded after posterior tibial and dorsal genital nerve stimulation. Rectal sensation was also assessed using electrical stimulation. Reproducible evoked potential recordings after anorectal stimulation were possible in only a minority of subjects and when recorded showed intersubject and intrasubject variation. In the constipated group there was a significant difference in rectal electrical sensation (P < 0.05) from controls. We conclude that peripheral sensory testing demonstrates an abnormality in severe constipation. However, cerebral evoked potentials cannot be reliably recorded after rectal stimulation, and when recorded the latencies are of too broad a range to discriminate between health and disease. This probably relates to the difference between somatic and visceral pathways.
Collapse
Affiliation(s)
- C T Speakman
- Sir Alan Parks Physiology Unit, St Mark's Hospital, London, UK
| | | | | |
Collapse
|
45
|
Abstract
Esophageal pain is transmitted via the sympathetic nervous system to the spinal cord, in which pain from visceral and somatic sources ascends to higher centers in the brain. Primary afferent neurons are bipolar, with the peripheral end specialized to be a sensory receptor. Nociceptors of somatosensory afferents are free nerve endings that can be activated by mechanical, thermal, or chemical stimuli. Esophageal nociceptive neurons have not been specifically identified but probably are also free nerve endings. Most esophageal spinal mechanoreceptors have been shown to be nociceptive. Some esophageal mechanonociceptors have a wide dynamic range and respond to physiologic and painful stimuli, while others have a high threshold of stimulation and are solely nociceptive. Esophageal spinal afferents have their cell bodies in the dorsal root ganglia and contain substance P and calcitonin gene-related peptide. These putative neurotransmitters are transported in both the peripheral and central directions of bipolar afferent neurons. Primary afferent neurons are likely to also contain an excitatory amino acid neurotransmitter such as glutamate. Centrally, nociceptive primary afferents terminate on neurons in specific layers of the dorsal horn of the spinal cord. Convergence of multiple visceral afferents with somatic afferents onto the same dorsal horn neurons may explain referred pain. A patient's inability to distinguish esophageal from cardiac pain may be due to convergence of pain pathways. Second-order neurons in the dorsal horn project in the anterolateral system to the brain. Within the anterolateral system, nociception ascends in the spinothalamic, spinoreticular, and spinomesencephalic tracts. The thalamus relays fast pain to the postcentral areas of the parietal lobe of the cortex. Pathways to the reticular formation are slow and may mediate the increased arousal that occurs in response to pain. The spinomesencephalic tract projects to midbrain sites including the periaqueductal gray. Organ-specific pathways in the brain have yet to be defined, but neuroanatomic tracing techniques employing neurotropic viruses are being developed. The perception of pain can be influenced at multiple levels, such as the receptor in the esophagus, the synapses in the dorsal horn of the spinal cord or thalamus, or the cortex. A fundamental mechanism of modulating nociception is descending inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
Affiliation(s)
- R B Lynn
- Division of Gastroenterology and Hepatology, Jefferson Medical College, Philadelphia, Pennsylvania 19107
| |
Collapse
|
46
|
Chien CH, Li SH, Shen CL. The ovarian innervation in the dog: a preliminary study for the base for electro-acupuncture. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1991; 35:185-92. [PMID: 1720797 DOI: 10.1016/0165-1838(91)90096-l] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The origin of the canine ovarian sensory and sympathetic nerves was studied by applying horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP (WGA-HRP) to the ovarian stroma and into the ovarian bursa. HRP/WGA-HRP positive neurons were found bilaterally in the dorsal root ganglia of T10 to L4 segment with the majority located in T13 to L2. In sympathetic paravertebral ganglia, labeled neurons were distributed bilaterally in ganglia from T11 to L4 with the majorities located in segments T13 to L2. Both distributions show ipsilateral predominance. Labeled prevertebral neurons were mainly located in the aorticorenal ganglion, ovarian ganglia and caudal mesenteric ganglion. No labeled neurons were found in the dorsal motor nucleus of vagus, nodose ganglia or sacral segment from S1 to S3. This study provides the possible morphological basis of electro-acupuncture concerning the somato-visceral reflex of the ovary.
Collapse
Affiliation(s)
- C H Chien
- Department of Anatomy, College of Medicine, National Cheng-Kung University, Tainan, Taiwan
| | | | | |
Collapse
|
47
|
Kashiba H, Senba E, Ueda Y, Tohyama M. Cell size and cell type analysis of calcitonin gene-related peptide-containing cutaneous and splanchnic sensory neurons in the rat. Peptides 1991; 12:101-6. [PMID: 2052485 DOI: 10.1016/0196-9781(91)90174-n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cell size, cell type and calcitonin gene-related peptide (CGRP)-like immunoreactivity were compared between cutaneous and splanchnic sensory neurons by means of a combination of fluorescent tracer and immunohistochemistry. Nineteen percent of cutaneous sensory neurons and 88% of splanchnic sensory neurons were shown to contain CGRP. The former cells were larger than the latter ones, which was also confirmed by the finding that about a half of the former cells contained 200 kDa subunit of neurofilament protein, while only 8% of the latter ones were positively stained. These findings suggest that most of the visceral CGRP-IR sensory neurons are small type B.
Collapse
Affiliation(s)
- H Kashiba
- Department of Physiology, Kansai College of Acupuncture Medicine, Osaka, Japan
| | | | | | | |
Collapse
|
48
|
Procacci P, Maresca M, Cersosimo RM. Visceral pain: pathophysiology and clinical aspects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 298:175-81. [PMID: 1950783 DOI: 10.1007/978-1-4899-0744-8_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- P Procacci
- Pain Center, University of Florence, Italy
| | | | | |
Collapse
|
49
|
Akeyson EW, Knuepfer MM, Schramm LP. Splanchnic input to thoracic spinal neurons and its supraspinal modulation in the rat. Brain Res 1990; 536:30-40. [PMID: 2085755 DOI: 10.1016/0006-8993(90)90005-v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The urinary responses of 62 T8-T11 spinal neurons were recorded extracellularly following electrical stimulation of the greater splanchnic nerve (GSN) in chloralose-anesthetized rats. Recorded neurons were found in both the dorsal and ventral horns. Fifty-seven neurons increased their firing rate in response to GSN stimulation; 8 of these exhibited biphasic responses consisting of excitations followed by inhibitions. Excitatory responses to GSN stimulation consisted of either one or two bursts with latencies consistent with activation by either A delta or C fibers. GSN stimulation inhibited 5 neurons. The effects of reversible spinalization on spontaneous activity and on both synchronous and non-synchronous (afterdischarge) GSN-evoked responses were investigated using a cooling probe on the spinal cord between C1 and C2. Of 19 neurons tested in this way, 9 exhibited opposite directional changes in their spontaneous activities and their GSN-evoked responses upon spinalization. Differential effects of cold-block on first and second bursts, or on A delta- and C-fiber mediated responses, were not usually observed. However, differential effects of cold-block on synchronous and non-synchronous portions of the overall GSN-evoked response were often observed in that their magnitudes often changed independently of one another. Supraspinal pathways contributed to GSN-evoked responses of several neurons because their responses were diminished during cooling while spontaneous activity was increased or unchanged. These decreases in the magnitude of the GSN-evoked response were not always accounted for by decreases in the synchronous portions of the responses. However, most neurons did exhibit decreases in the number of non-synchronous responses, or afterdischarges, during spinal cooling, exhibiting in some cases biphasic responses. This study provides evidence for strong supraspinal regulation of splanchnic afferent input to the spinal cord of the rat. Further, this regulation exhibits some specificity toward different portions of splanchnic-evoked responses in spinal neurons.
Collapse
Affiliation(s)
- E W Akeyson
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | | | | |
Collapse
|
50
|
Kashiba H, Senba E, Ueda Y, Tohyama M. Calbindin D28k-containing splanchnic and cutaneous dorsal root ganglion neurons of the rat. Brain Res 1990; 528:311-6. [PMID: 2271930 DOI: 10.1016/0006-8993(90)91673-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Calbindin D28k (CaBP)-containing splanchnic and cutaneous sensory neurons in the rat dorsal root ganglia (DRGs) were investigated immunocytochemically in combination with a fluorescent dye tracer (Fluoro gold). About 15% of the DRG neurons at Th9-10 levels showed CaBP-like immunoreactivity. Eighty-four % of the splanchnic sensory neurons were immunoreactive to CaBP, while only 3% of the cutaneous sensory neurons were. The diameters of the splanchnic and cutaneous sensory neurons containing CaBP were 23.4 +/- 6.3 microns and 38.4 +/- 8.8 microns, respectively. Splanchnic sensory neurons containing CaBP were sensitive to capsaicin while cutaneous ones were not. These findings suggest that CaBP-containing splanchnic and cutaneous sensory neurons constitute different subgroups among the DRG neurons at the lower thoracic level.
Collapse
Affiliation(s)
- H Kashiba
- Department of Physiology, Kansai College of Acupuncture Medicine, Osaka, Japan
| | | | | | | |
Collapse
|