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Viguier F, Michot B, Kayser V, Bernard JF, Vela JM, Hamon M, Bourgoin S. GABA, but not opioids, mediates the anti-hyperalgesic effects of 5-HT7 receptor activation in rats suffering from neuropathic pain. Neuropharmacology 2012; 63:1093-106. [DOI: 10.1016/j.neuropharm.2012.07.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 07/03/2012] [Accepted: 07/10/2012] [Indexed: 12/12/2022]
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Blyth BJ, Bazarian JJ. Traumatic alterations in consciousness: traumatic brain injury. Emerg Med Clin North Am 2010; 28:571-94. [PMID: 20709244 DOI: 10.1016/j.emc.2010.03.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Mild traumatic brain injury (mTBI) refers to the clinical condition of transient alteration of consciousness as a result of traumatic injury to the brain. The priority of emergency care is to identify and facilitate the treatment of rare but potentially life-threatening intracranial injuries associated with mTBI through the judicious application of appropriate imaging studies and neurosurgical consultation. Although post-mTBI symptoms quickly and completely resolve in the vast majority of cases, a significant number of patients will complain of lasting problems that may cause significant disability. Simple and early interventions such as patient education and appropriate referral can reduce the likelihood of chronic symptoms. Although definitive evidence is lacking, mTBI is likely to be related to significant long-term sequelae such as Alzheimer disease and other neurodegenerative processes.
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Affiliation(s)
- Brian J Blyth
- Department of Emergency Medicine, Center for Neural Development and Disease, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, USA.
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OSHIMA H, KATAYAMA Y. Neuroethics of Deep Brain Stimulation for Mental Disorders: Brain Stimulation Reward in Humans. Neurol Med Chir (Tokyo) 2010; 50:845-52. [DOI: 10.2176/nmc.50.845] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hideki OSHIMA
- Department of Functional Morphology, Nihon University School of Medicine
| | - Yoichi KATAYAMA
- Department of Neurological Surgery, Nihon University School of Medicine
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Kohlmeier KA, Soja PJ, Kristensen MP. Disparate cholinergic currents in rat principal trigeminal sensory nucleus neurons mediated by M1 and M2 receptors: a possible mechanism for selective gating of afferent sensory neurotransmission. Eur J Neurosci 2006; 23:3245-58. [PMID: 16820015 DOI: 10.1111/j.1460-9568.2006.04875.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neurons situated in the principal sensory trigeminal nucleus (PSTN) convey orofacial sensory inputs to thalamic relay regions and higher brain centres, and the excitability of these ascending tract cells is modulated across sleep/wakefulness states and during pain conditions. Moreover, acetylcholine release changes profoundly across sleep/wakefulness states and ascending sensory neurotransmission is altered by cholinergic agonists. An intriguing possibility is, therefore, that cholinergic mechanisms mediate such state-dependent modulation of PSTN tract neurons. We tested the hypotheses that cholinergic agonists can modulate PSTN cell excitability and that such effects are mediated by muscarinic receptor subtypes, using patch-clamp methods in rat and mouse. In all examined cells, carbachol elicited an electrophysiological response that was independent of action potential generation as it persisted in the presence of tetrodotoxin. Responses were of three types: depolarization, hyperpolarization or a biphasic response consisting of hyperpolarization followed by depolarization. In voltage-clamp mode, carbachol evoked corresponding inward, outward or biphasic currents. Moreover, immunostaining for the vesicle-associated choline transporter showed cholinergic innervation of the PSTN. Using muscarinic receptor antagonists, we found that carbachol-elicited PSTN neuron hyperpolarization was mediated by M2 receptors and depolarization, in large part, by M1 receptors. These data suggest that acetylcholine acting on M1 and M2 receptors may contribute to selective excitability enhancement or depression in individual, rostrally projecting sensory neurons. Such selective gating effects via cholinergic input may play a functional role in modulation of ascending sensory transmission, including across behavioral states typified by distinct cholinergic tone, e.g. sleep/wakefulness arousal levels or neuropathic pain conditions.
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Affiliation(s)
- Kristi A Kohlmeier
- Department of Physiology, New York Medical College, Valhalla, NY 10595, USA.
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Carlson JD, Selden NR, Heinricher MM. Nocifensive reflex-related on- and off-cells in the pedunculopontine tegmental nucleus, cuneiform nucleus, and lateral dorsal tegmental nucleus. Brain Res 2005; 1063:187-94. [PMID: 16256081 DOI: 10.1016/j.brainres.2005.09.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 09/23/2005] [Accepted: 09/27/2005] [Indexed: 11/16/2022]
Abstract
Cholinergic projections from the pedunculopontine tegmental nucleus (PPTg) to the rostral ventromedial medulla (RVM) have been implicated in nociceptive modulation. The goal of this study was to identify neurons with nocifensive reflex-related activity in the mesopontine tegmentum including the PPTg. This study used the same behavioral neurophysiological classification system to identify neurons as has been extensively described in the RVM. Extracellular microelectrode recording was conducted in lightly anesthetized rats. Changes in firing associated with the noxious heat-evoked tail flick reflex were used to classify neurons as "on-cells" (displayed a burst in neuronal activity associated with the reflex), "off-cells" (displayed a pause in activity), and neutral cells (showed no response). Of 188 neurons studied in 23 rats, 77 were classified as on-cells, 14 as off-cells, the remainder as neutral cells. Recordings during periods without noxious stimulation found that some of the on- and off-cells displayed spontaneous transitions between active and silent periods termed cell cycling. The distribution of on- and off-cells in the mesopontine tegmentum overlapped and included the cholinergic PPTg and lateral dorsal tegmental nucleus identified by NADPH diaphorase staining, as well as the cuneiform nucleus and periaqueductal gray. The mesopontine tegmentum thus contains nocifensive reflex-related neurons with neurophysiological characteristics similar to those reported in the RVM. Neurons showing reflex-related activity were frequently encountered in the cholinergic PPTg and LDTg. Further studies will be required to determine whether these neurons modulate nociception through a link to the RVM.
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Affiliation(s)
- Jonathan Dennis Carlson
- Department of Neurological Surgery, L-472, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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Wallace BA, Ashkan K, Benabid AL. Deep brain stimulation for the treatment of chronic, intractable pain. Neurosurg Clin N Am 2004; 15:343-57, vii. [PMID: 15246342 DOI: 10.1016/j.nec.2004.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Deep brain stimulation (DBS) was first used for the treatment of pain in 1954. Since that time, remarkable advances have been made in the field of DBS, largely because of the resurgence of DBS for the treatment of movement disorders. Although DBS for pain has largely been supplanted by motor cortex and spinal cord stimulation during the last decade, no solid evidence exists that these alternative modalities truly offer improved outcomes. Furthermore, nuclei not yet fully explored are known to play a role in the transmission and modulation of pain. This article outlines the history of DBS for pain, pain classification, patient selection criteria, DBS target selection, surgical techniques, indications for DBS (versus ablative techniques), putative new DBS targets, complications, and the outcomes associated with DBS for pain.
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Affiliation(s)
- Bradley A Wallace
- Department of Neurosurgery, University of Florida, Gainesville 32610, USA.
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Abstract
Deep brain stimulation (DBS) plays an important role in the treatment of chronic pain when other less invasive treatment modalities have been exhausted. DBS is an apparently safe and effective treatment option for a select group of patients. Further research into the mechanisms of pain relief by DBS and careful prospective outcomes studies should help to define better the optimal techniques for DBS and clarify which patient populations may be best helped by this interventional procedure.
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Affiliation(s)
- Robert M Levy
- Departments of Neurological Surgery and Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Monassi CR, Leite-Panissi CR, Menescal-de-Oliveira L. Ventrolateral periaqueductal gray matter and the control of tonic immobility. Brain Res Bull 1999; 50:201-8. [PMID: 10566982 DOI: 10.1016/s0361-9230(99)00192-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Tonic immobility is an inborn defensive behavior characterized by a temporary state of profound and reversible motor inhibition elicited by some forms of physical restraint. The periaqueductal gray matter (PAG) contains neural circuits involved in descending pain modulation, as well as in the modulation of TI. We have reported previously that the cholinergic stimulation of the ventrolateral PAG increases the duration of TI in guinea pigs. In the present study, we attempted to characterize further the modulation of TI by pharmacological alteration of the neurochemistry of the ventrolateral PAG circuitry. We observed that both cholinergic (carbachol, 5.4 nmol/0.2 microl) and opioidergic stimulations (morphine, 4.48 nmol/0.2 microl) of the ventrolateral PAG increase the duration of TI and that these effects can be reversed by pre-treatment with naloxone (2.74 nmol/0.2 microl). Our results also showed that microinjection of the GABAergic agonist muscimol (1, 0.5, and 0.26 nmol/0.2 microl) decreased the duration of TI episodes, while microinjection of the GABAergic antagonist bicuculline (1 nmol/microl) increased it. Moreover, we observed that preadministration of muscimol (0.13 nmol/0.2 microl) at a dose that had no effect per se at this site antagonized the potentiating effect of morphine. Our results suggest that this modulation of TI from the ventrolateral PAG circuitry is accomplished by a complex interaction of cholinergic, opioidergic, and GABAergic mechanisms, similar to that proposed for descending antinociceptive circuits.
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Affiliation(s)
- C R Monassi
- Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
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Abstract
Increases in the expression of immediate early genes have been shown to occur in the lumbar spinal cord dorsal horn after peripheral inflammation. Given that the pontine parabrachial nucleus has been implicated in nociceptive as well as antinociceptive processes and is reciprocally connected with the spinal cord dorsal horn, it seems likely that peripheral inflammation will cause alterations in immediate early gene expression in this nucleus. To test this hypothesis we examined cFos-like immunoreactivity in a rodent complete Freund's adjuvant-induced peripheral inflammatory model of persistent nociception. Unilateral hind paw injections of complete Freund's adjuvant produced inflammation, hyperalgesia of the affected limb, and alterations in open field behaviors. Immunocytochemical analysis demonstrated a bilateral increase in cFos-like immunoreactivity in the lateral and Kolliker-Fuse subdivisions of the parabrachial nucleus at 6 and 24 hours postinjection and an ipsilateral decrease below basal levels in the Kolliker-Fuse subdivision at 96 hours postinjection when compared to saline controls. Taken together, these results suggest that select parabrachial neurons are activated by noxious somatic inflammation. These active parabrachial neurons are likely to participate in ascending nociceptive and/or descending antinociceptive pathways.
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Affiliation(s)
- L L Bellavance
- Neuroscience Program and Department of Veterinary PathoBiology, University of Minnesota, St. Paul 55108, USA
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Young RF, Tronnier V, Rinaldi PC. Chronic stimulation of the Kölliker-Fuse nucleus region for relief of intractable pain in humans. J Neurosurg 1992; 76:979-85. [PMID: 1588433 DOI: 10.3171/jns.1992.76.6.0979] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Chronic electrical stimulation in the periventricular or periaqueductal gray matter regions and the thalamic somatosensory relay nuclei (ventralis posteromedialis and ventralis posterolateralis) provides long-term pain relief in about 50% of patients with intractable pain refractory to other conservative and/or surgical measures. To enhance the success of electrical stimulation in relief of pain, alternative brain and brain-stem targets have been sought. A series of laboratory studies indicated that the Kölliker-Fuse nucleus and the parabrachial region may provide appropriate alternatives to the "classic" targets. This report describes six patients with intractable chronic pain of nociceptive or central origin, in whom an electrode was stereotactically implanted in the region of the Kölliker-Fuse nucleus. Kölliker-Fuse nucleus stimulation alone or in combination with stimulation in the periaqueductal/periventricular gray matter region or the somatosensory thalamic nuclei provided excellent pain relief in three of the six patients.
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Affiliation(s)
- R F Young
- Division of Neurological Surgery, University of California, Irvine Medical Center, Orange
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12
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González-Mariscal G, Gómora P, Caba M, Beyer C. Copulatory analgesia in male rats ensues from arousal, motor activity, and genital stimulation: blockage by manipulation and restraint. Physiol Behav 1992; 51:775-81. [PMID: 1594675 DOI: 10.1016/0031-9384(92)90115-i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effect of copulation on the vocalization threshold to tail shock (VTTS) was assessed in freely-moving, sexually experienced, Wistar male rats. Mean VTTS during the first copulation was 40% above the baseline values and slightly decreased during the first postejaculatory interval (PEI; 28% above baseline). VTTS mean values further increased during the second copulatory series (93% above baseline and 63% during the PEI). Testing at the same intervals in noncopulating rats did not induce analgesia. VTTS values also increased after the display of either one ejaculation (E), five intromissions (I), or five mounts (M), the analgesia persisting for at least 20 min. Analgesia following M was smaller and shorter than that observed after either I or E. Analgesia developed gradually during copulation since VTTS values after five I were significantly higher than those after one I. The incidence of vocalizations to suprathreshold shocks (STS, 20% above the VTTS) occurring during various phases of copulation was also studied to determine the onset and short-term fluctuations of copulatory analgesia. The proportion of STS inducing vocalizations decreased from 91% (mean of individual proportions) before copulation, to 24% during copulation, and to 25% during the PEI. A maximal reduction in the proportion of vocalizations to STS was found during the last third of copulation. Nearly all vocalizations to STS during copulation occurred when subjects were quiescent, while few or no vocalizations occurred when rats were engaged in sexual activity, i.e., during M, I, or penile grooming. In contrast to the above-mentioned data, no significant analgesia was observed using the tail-flick latency test (TFL) following either E, five I, or five M.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G González-Mariscal
- Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, Mexico
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Foreman RD. Organization of the Spinothalamic Tract as a Relay for Cardiopulmonary Sympathetic Afferent Fiber Activity. ACTA ACUST UNITED AC 1989. [DOI: 10.1007/978-3-642-74058-9_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Girardot MN, Brennan TJ, Martindale ME, Foreman RD. Effects of stimulating the subcoeruleus-parabrachial region on the non-noxious and noxious responses of T1-T5 spinothalamic tract neurons in the primate. Brain Res 1987; 409:19-30. [PMID: 3034377 DOI: 10.1016/0006-8993(87)90737-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of electrical stimulation of the subcoeruleus-parabrachial (SC-PB) region on the discharge rate of upper thoracic spinothalamic tract (STT) neurons were investigated in 21 monkeys anesthetized with alpha-chloralose. STT cells were antidromically activated from the medial thalamus (MT) and the ventral posterior lateral nucleus (VPL) and received viscerosomatic convergent input from the cardiopulmonary sympathetic afferents and the left chest-forearm region. Stimulation of the SC-PB region inhibited the activity of all 30 STT neurons studied in the T1-T5 regions of the spinal cord. The minimum average current required to decrease the discharge rate of 22 cells exhibiting spontaneous activity was 89 +/- 10 microA (100 Hz, 100 microseconds duration). Currents as high as 300 microA completely inhibited the activity of most cells. Examination of the importance of frequency of stimulation from the SC-PB area on 8 cells revealed that impulses of at least 40 Hz (208 +/- 37 microA, 100 microseconds duration) were necessary to inhibit the spontaneous activity by 60%. Higher frequencies produced greater degrees of inhibition. Stimulation of the SC-PB region also inhibited the response of 23 of 23 neurons excited by noxious pinch and 11 of 11 wide dynamic range cells stimulated by innocuous input such as blowing or brushing hair. No differences in the inhibition produced by SC-PB stimulation on cells projecting to VPL (n = 20), MT (n = 5), or both VPL and MT (n = 5) were observed. These results demonstrate that the SC-PB region may be an important brainstem site for descending inhibition of both noxious and innocuous somatic input to upper thoracic STT cells in the primate.
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Ossipov MH, Gebhart GF. Opioid, cholinergic and alpha-adrenergic influences on the modulation of nociception from the lateral reticular nucleus of the rat. Brain Res 1986; 384:282-93. [PMID: 2877712 DOI: 10.1016/0006-8993(86)91164-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The lateral reticular nucleus (LRN) has been identified as an area in the caudal medulla involved in the centrifugal modulation of spinal nociceptive transmission and withdrawal reflexes. The data presented in this report further support a role for the LRN in the modulation of nociceptive responses. It was confirmed in the present study that focal electrical stimulation in the LRN inhibits the nociceptive tail-flick (TF) reflex at low intensities of stimulation in lightly pentobarbital-anesthetized rats. Aversive effects, however, were typically produced at similar and higher intensities of stimulation in the LRN in the same rats in the awake state. It was also determined that an inhibitory modulation of nociceptive responses organized both spinally and supraspinally could be activated independently by muscarinic cholinergic or opioid mechanisms in the LRN. Microinjection of morphine into the LRN in conscious rats produced an antinociception in both TF and hot plate (HP) tests which could be attenuated significantly by naloxone, but not atropine, previously microinjected into the same site in the LRN. Carbachol microinjected into the LRN also produced an antinociception which was attenuated significantly by atropine but not naloxone previously microinjected into the same site in the LRN. In contrast, the microinjection of clonidine or norepinephrine into the LRN either did not affect or shortened significantly response latencies in the TF and HP tests. These results further establish that the LRN contributes to the modulation of nociception. Opioid and cholinergic influences in the LRN appear to independently activate inhibition of responding to nociceptive stimuli organized either spinally or supraspinally, although descending inhibition was most clearly activated. An action at alpha 2 adrenoceptors in the LRN, conversely, produces an hyperalgesia as reflected by shortened latencies to respond in TF and HP tests.
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Schneider JS. Interactions between the basal ganglia, the pontine parabrachial region, and the trigeminal system in cat. Neuroscience 1986; 19:411-25. [PMID: 3774149 DOI: 10.1016/0306-4522(86)90271-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Anatomical studies utilizing wheat germ lectin-bound horseradish peroxidase demonstrated direct connections between the pontine parabrachial region and the substantia nigra pars reticulata and to a lesser extent, the entopeduncular nucleus as well as a number of other forebrain regions including the amygdala, hypothalamus, thalamus, bed nucleus stria terminalis and substantia innominata. The pontine parabrachial region was also shown to receive direct inputs from the spinal trigeminal system and to send axons to areas surrounding trigeminal and hypoglossal motor areas. Once the anatomical connections were determined, electrophysiological studies were undertaken to investigate some of the functional aspects of these connections between the pontine parabrachial, basal ganglia and trigeminal systems. Extracellular single unit recordings were obtained from 228 cells in the dorsal pontine parabrachial region of the cat. These cells were tested for responsiveness to trigeminal sensory stimulation and activation of basal ganglia outputs (i.e. substantia nigra and entopeduncular nucleus). Twenty-two percent of pontine parabrachial cells responded to only trigeminal stimulation; 4% responded to entopeduncular nucleus only; 37% responded to substantia nigra only, and 28% responded to both substantia nigra and trigeminal stimulation. Furthermore, 43% of pontine parabrachial cells with both substantia nigra and sensory response had the sensory response altered by a preceding stimulus to the substantia nigra. Thus, the substantia nigra is shown to exert influences on both the spontaneous activities and afferent responses of pontine parabrachial neurons. The significance of these findings are discussed in relation to the importance of descending basal ganglia influences and ascending influences from the pontine parabrachial region on various sensorimotor activities.
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Hayes RL, Katayama Y. Range of environmental stimuli producing nociceptive suppression: implications for neural mechanisms. Ann N Y Acad Sci 1986; 467:1-13. [PMID: 3524376 DOI: 10.1111/j.1749-6632.1986.tb14614.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Initial studies of environmentally induced analgesia in the rat established several important characteristics of this phenomenon. We demonstrated that stressful environmental stimuli were not sufficient to produce nociceptive suppression. However, emphasis by many researchers on stress-related analgesia has limited studies of the range of environmental contexts producing nociceptive suppression and handicapped efforts to describe neural mechanisms mediating EIA. Another feature of EIA was the observation that the nervous system might contain multiple opiate and non-opiate systems capable of modulating nociceptive responses. Although previous research had recognized the possibility of endogenous opiate analgesic systems, little attention had been given to non-opiate analgesic mechanisms. Since it seems unlikely that multiple systems would serve purely redundant roles, it seemed reasonable to speculate that at least some of these systems may mediate other modulatory functions in addition to regulating sensory information on noxious stimuli. The observation that some environmental conditions could increase nociceptive responses certainly indicated that environmentally induced nociceptive modulation was not restricted to analgesia. These and other observations lead us to suspect that neural mechanisms mediating at least some forms of EIA could be related to mechanisms mediating more general modulating processes associated with selective attention, orienting, or arousal. Subsequent studies in the primate established that changes in vigilance demands, stimulus relevance, and stimulus predictability could modulate responses of medullary dorsal horn nociceptors coding sensory-discriminative information on noxious thermal stimuli. However, these studies provided no information on the neural mechanisms mediating this modulation. Later studies in cats described an endogenous, non-narcotic analgesic system representing a subcomponent of a larger cholinergic system principally involved in regulating animals' responsiveness to external stimuli. Research also indicated that this cholinergic analgesic system could function physiologically to modulate nociceptive responsiveness in the presence of certain environmental stimuli but not others. Considered together, data from these studies indicate that, while stress is not sufficient to produce analgesia, a variety of environmental conditions can modulate nociceptive input. A number of different neural systems could contribute EIA associated with various stimuli. It is possible that the regulation of nociceptive input is not the exclusive, or even principal, consequence of normal activity within certain of these systems.
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Parabrachial Modulation of Pain and Blood Pressure. J Neurosurg 1985. [DOI: 10.3171/jns.1985.63.3.0478a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Katayama Y, Glisson JD, Becker DP, Hayes RL. Concussive head injury producing suppression of sensory transmission within the lumbar spinal cord in cats. J Neurosurg 1985; 63:97-105. [PMID: 2989452 DOI: 10.3171/jns.1985.63.1.0097] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This study examines the effects of concussive levels of a fluid-percussion head injury on sensory transmission within the lumbar spinal cord of the cat. Primary afferent depolarization (PAD) was suppressed for 2 to 5 minutes following injury, as assessed by dorsal root potentials and augmentation of antidromic dorsal root potentials, both evoked by stimulation of adjacent dorsal roots. Polysynaptic reflex discharges in ventral root potentials evoked by dorsal root stimulation were also profoundly suppressed during this same period, even when spontaneous and monosynaptic reflex discharges were facilitated. Changes in PAD produced by injury were abolished by spinal cord transection, but were not affected by midpontine transection. These findings suggest that concussive head injury can produce suppression of segmental sensory transmission by neurally mediated processes involving the bulbar brain stem. Recordings of dorsal root resting potentials, antidromic dorsal root potentials, and reductions of antidromic dorsal root potentials induced by tetanic root stimulation indicated that depressed segmental sensory function produced by injury was due to suppression of postsynaptic interneuronal transmission rather than to excitability changes in primary afferent fibers. Somatosensory cortical potentials evoked by dorsal root stimulation were profoundly depressed at the same time as segmental sensory transmission was suppressed, suggesting that suppressed segmental sensory transmission may also contribute to suppression of ascending sensory transmission. It is hypothesized that transmission failure of interneuronal systems in the initial period following insult may be a general response occurring in wide areas of the central nervous system, and not restricted to areas to which mechanical stress is directly applied. This response pattern may result from indiscriminate activation of interconnected excitatory and inhibitory elements of interneuronal systems.
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Katayama Y, Reuther S, Dixon CE, Becker DP, Hayes RL. Dissociation of endogenous components of auditory evoked potentials following carbachol microinjection into the cholinoceptive pontine inhibitory area. Brain Res 1985; 334:366-71. [PMID: 3995327 DOI: 10.1016/0006-8993(85)90234-3] [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: 01/08/2023]
Abstract
Microinjections of the cholinergic agonist, carbachol, into an area ventromedial to the principal nucleus of the locus coeruleus produce pronounced suppression of postural somatomotor and sympathetic visceromotor functions, and profound unresponsiveness to external stimuli. In order to clarify whether this unresponsiveness is due exclusively to disruption of motor components of various behavioral responses, we examined changes in the endogenous components of auditory evoked potentials recorded in conjunction with a tone discrimination task. Concomitant with carbachol-induced behavioral unresponsiveness, the late positive component (LPC) at 250-350 ms disappeared, while the early positive component at 80-150 ms was enhanced. This result suggests that, after the onset of carbachol-induced behavioral unresponsiveness, external stimuli enter the brain but are not integrated in neural processes reflected in LPC which has previously been implicated in processes mediating orienting responses, selective attention, and/or cognitive evaluation.
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DeSalles AA, Katayama Y, Becker DP, Hayes RL. Pain suppression induced by electrical stimulation of the pontine parabrachial region. Experimental study in cats. J Neurosurg 1985; 62:397-407. [PMID: 3871845 DOI: 10.3171/jns.1985.62.3.0397] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cholinergic stimulation by microinjection of drugs into a region surrounding the lateral half of the brachium conjunctivum selectively produces a non-opiate form of pain suppression in the cat. Since this suppression does not appear to involve neural systems that mediate morphine analgesia, stimulation of this pontine parabrachial region (PBR) may potentially be useful for control of human pain resistant or tolerant to opiate treatment. Because of technical problems associated with the clinical use of microinjection techniques in the human brain, we investigated whether electrical stimulation of the PBR can produce pain suppression similar to pain suppression produced by cholinergic stimulation. The results indicate that electrical stimulation of an area generally corresponding to the PBR can also produce significant pain suppression. Although the PBR is a region previously implicated in a variety of behavioral and physiological functions, the stimulation parameters that produce maximal pain suppressive effects (namely, low frequency and relatively low intensity) were not associated with noticeable changes in such functions. The prolonged onset period and persistent analgesic effects outlasting the period of stimulation--features that have been reported in other studies of brain stimulation-produced pain suppression--were observed in the present study. The time course of pain suppression did not parallel other changes in behavioral and physiological functions. These data indicate that electrical stimulation of the PBR, under certain stimulation parameters, can activate previously demonstrated neural populations related to pain suppression without affecting neural elements contributing to other behavioral or physiological functions. The authors suggest that electrical stimulation of the PBR may be clinically applicable for treatment of human pain.
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Hayes RL, Katayama Y, Watkins LR, Becker DP. Bilateral lesions of the dorsolateral funiculus of the cat spinal cord: effects on basal nociceptive reflexes and nociceptive suppression produced by cholinergic activation of the pontine parabrachial region. Brain Res 1984; 311:267-80. [PMID: 6498485 DOI: 10.1016/0006-8993(84)90089-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In cats, bilateral microinjections of the cholinergic agonist, carbachol (0.6 micrograms in 0.2 microliter), into an area surrounding the lateral half of the brachium conjunctivum (BC) produces a non-narcotic suppression of nociceptive responses, as assessed by flexion reflexes (tail-flick and calibrated pinch tests). Bilateral lesions of the dorsolateral funiculi (DLF) of the thoracic spina cord (T2) significantly reduced the magnitude of this nociceptive suppression. Nociceptive suppression following carbachol microinjections into sites along the dorsal aspect of BC was reduced by DLF lesions to a greater degree than nociceptive suppression following injections into sites within or ventral to BC. Relatively superficial DLF lesions produced reductions in nociceptive suppression which were equivalent to reductions induced by deeper lesions. DLF lesions, either superficial or deep, produced equivalent, reliable decreases in tail-flick test assessments of baseline nociceptive thresholds. The magnitude of decreases in baseline nociceptive thresholds produced by DLF lesions was not correlated with the magnitude of reduction of carbachol-induced suppression of nociceptive responses, indicating that DLF lesions suppress anti-nociception independent of baseline alterations. These data suggest that non-narcotic analgesia produced by cholinergic activation of cells along the dorsal aspect of BC may be predominantly mediated by fibers descending within the DLF. However, results of the retrograde horseradish peroxidase (HRP) tracing studies reported in the present investigation indicate that this pain suppression is probably mediated by polysynaptic pathways since this region dorsal to BC projects neither through DLF nor extra-DLF pathways. Retrograde HRP data show that areas ventral to and including BC projects to the cord via both DLF and extra-DLF pathways. Since DLF lesions were less effective in reducing analgesia attained from ventral compared to dorsal sites, spinal pathways other than DLF may mediate reflex suppression following carbachol microinjection into these more ventral sites. Possible cholinergic contributions to endogenous, non-opiate forms of analgesia are discussed.
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Abstract
A review of pharmacological, neuroanatomical, electrophysiological, and behavioral data indicates that systems controlling cardiovascular function are closely coupled to systems modulating the perception of pain. This view is directly supported by experiments from our laboratory showing that activation of either the cardiopulmonary baroreceptor reflex arc or the sinoaortic baroreceptor reflex arc induces antinociception. The outcomes of studies using pharmacological treatments, peripheral nerve stimulation, peripheral nerve resection, and CNS lesions are also presented as a preliminary means of characterizing cardiovascular input to pain regulatory systems. The network formed by these systems is proposed to participate in the elaboration of adaptive responses to physical and psychological stressors at various levels of the neuroaxis, and possibly to participate in "diseases of adaptation." In particular, the present analysis suggests that the inhibition of pain brought about by elevations in either arterial or venous blood pressure may provide a form of psychophysiological relief under situations of stress and contribute to the development of essential hypertension in humans.
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