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da Cunha PHM, de Andrade DC. The deep and the deeper: Spinal cord and deep brain stimulation for neuropathic pain. Presse Med 2024; 53:104231. [PMID: 38636785 DOI: 10.1016/j.lpm.2024.104231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Neuropathic pain occurs in people experiencing lesion or disease affecting the somatosensorial system. It is present in 7 % of the general population and may not fully respond to first- and second-line treatments in up to 40 % of cases. Neuromodulation approaches are often proposed for those not tolerating or not responding to usual pharmacological management. These approaches can be delivered surgically (invasively) or non-invasively. Invasive neuromodulation techniques were the first to be employed in neuropathic pain. Among them is spinal cord stimulation (SCS), which consists of the implantation of epidural electrodes over the spinal cord. It is recommended in some guidelines for peripheral neuropathic pain. While recent studies have called into question its efficacy, others have provided promising data, driven by advances in techniques, battery capabilities, programming algorithms and software developments. Deep brain stimulation (DBS) is another well-stablished neuromodulation therapy routinely used for movement disorders; however, its role in pain management remains limited to specific research centers. This is not only due to variable results in the literature contesting its efficacy, but also because several different brain targets have been explored in small trials, compromising comparisons between these studies. Structures such as the periaqueductal grey, posterior thalamus, anterior cingulate cortex, ventral striatum/anterior limb of the internal capsule and the insula are the main targets described to date in literature. SCS and DBS present diverse rationales for use, mechanistic backgrounds, and varying levels of support from experimental studies. The present review aims to present their methodological details, main mechanisms of action for analgesia and their place in the current body of evidence in the management of patients with neuropathic pain, as well their particularities, effectiveness, safety and limitations.
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Affiliation(s)
| | - Daniel Ciampi de Andrade
- Center for Neuroplasticity and Pain, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
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Pagano RL, Dale CS, Campos ACP, Hamani C. Translational aspects of deep brain stimulation for chronic pain. FRONTIERS IN PAIN RESEARCH (LAUSANNE, SWITZERLAND) 2023; 3:1084701. [PMID: 36713643 PMCID: PMC9874335 DOI: 10.3389/fpain.2022.1084701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 12/22/2022] [Indexed: 01/13/2023]
Abstract
The use of deep brain stimulation (DBS) for the treatment of chronic pain was one of the first applications of this technique in functional neurosurgery. Established brain targets in the clinic include the periaqueductal (PAG)/periventricular gray matter (PVG) and sensory thalamic nuclei. More recently, the anterior cingulum (ACC) and the ventral striatum/anterior limb of the internal capsule (VS/ALIC) have been investigated for the treatment of emotional components of pain. In the clinic, most studies showed a response in 20%-70% of patients. In various applications of DBS, animal models either provided the rationale for the development of clinical trials or were utilized as a tool to study potential mechanisms of stimulation responses. Despite the complex nature of pain and the fact that animal models cannot reliably reflect the subjective nature of this condition, multiple preparations have emerged over the years. Overall, DBS was shown to produce an antinociceptive effect in rodents when delivered to targets known to induce analgesic effects in humans, suggesting a good predictive validity. Compared to the relatively high number of clinical trials in the field, however, the number of animal studies has been somewhat limited. Additional investigation using modern neuroscience techniques could unravel the mechanisms and neurocircuitry involved in the analgesic effects of DBS and help to optimize this therapy.
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Affiliation(s)
- Rosana L. Pagano
- Laboratory of Neuroscience, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Camila S. Dale
- Laboratory of Neuromodulation and Experimental Pain, Department of Anatomy, University of São Paulo, São Paulo, Brazil
| | | | - Clement Hamani
- Sunnybrook Research Institute, Hurvitz Brain Sciences Centre, Toronto, ON, Canada,Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON, Canada,Division of Neurosurgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada,Correspondence: Clement Hamani
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Seamans JK, Floresco SB. Event-based control of autonomic and emotional states by the anterior cingulate cortex. Neurosci Biobehav Rev 2021; 133:104503. [PMID: 34922986 DOI: 10.1016/j.neubiorev.2021.12.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 11/25/2021] [Accepted: 12/14/2021] [Indexed: 12/25/2022]
Abstract
Despite being an intensive area of research, the function of the anterior cingulate cortex (ACC) remains somewhat of a mystery. Human imaging studies implicate the ACC in various cognitive functions, yet surgical ACC lesions used to treat emotional disorders have minimal lasting effects on cognition. An alternative view is that ACC regulates autonomic states, consistent with its interconnectivity with autonomic control regions and that stimulation evokes changes in autonomic/emotional states. At the cellular level, ACC neurons are highly multi-modal and promiscuous, and can represent a staggering array of task events. These neurons nevertheless combine to produce highly event-specific ensemble patterns that likely alter activity in downstream regions controlling emotional and autonomic tone. Since neuromodulators regulate the strength of the ensemble activity patterns, they would regulate the impact these patterns have on downstream targets. Through these mechanisms, the ACC may determine how strongly to react to the very events its ensembles represent. Pathologies arise when specific event-related representations gain excessive control over autonomic/emotional states.
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Affiliation(s)
- Jeremy K Seamans
- Depts. of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6B2T5, Canada.
| | - Stan B Floresco
- Depts. of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6B2T5, Canada
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Role of the Anterior Cingulate Cortex in Translational Pain Research. Neurosci Bull 2021; 37:405-422. [PMID: 33566301 DOI: 10.1007/s12264-020-00615-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023] Open
Abstract
As the most common symptomatic reason to seek medical consultation, pain is a complex experience that has been classified into different categories and stages. In pain processing, noxious stimuli may activate the anterior cingulate cortex (ACC). But the function of ACC in the different pain conditions is not well discussed. In this review, we elaborate the commonalities and differences from accumulated evidence by a variety of pain assays for physiological pain and pathological pain including inflammatory pain, neuropathic pain, and cancer pain in the ACC, and discuss the cellular receptors and signaling molecules from animal studies. We further summarize the ACC as a new central neuromodulation target for invasive and non-invasive stimulation techniques in clinical pain management. The comprehensive understanding of pain processing in the ACC may lead to bridging the gap in translational research between basic and clinical studies and to develop new therapies.
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Friesner ID, Martinez E, Zhou H, Gould JD, Li A, Chen ZS, Zhang Q, Wang J. Ketamine normalizes high-gamma power in the anterior cingulate cortex in a rat chronic pain model. Mol Brain 2020; 13:129. [PMID: 32967695 PMCID: PMC7513294 DOI: 10.1186/s13041-020-00670-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/14/2020] [Indexed: 11/18/2022] Open
Abstract
Chronic pain alters cortical and subcortical plasticity, causing enhanced sensory and affective responses to peripheral nociceptive inputs. Previous studies have shown that ketamine had the potential to inhibit abnormally amplified affective responses of single neurons by suppressing hyperactivity in the anterior cingulate cortex (ACC). However, the mechanism of this enduring effect has yet to be understood at the network level. In this study, we recorded local field potentials from the ACC of freely moving rats. Animals were injected with complete Freund’s adjuvant (CFA) to induce persistent inflammatory pain. Mechanical stimulations were administered to the hind paw before and after CFA administration. We found a significant increase in the high-gamma band (60–100 Hz) power in response to evoked pain after CFA treatment. Ketamine, however, reduced the high-gamma band power in response to evoked pain in CFA-treated rats. In addition, ketamine had a sustained effect on the high-gamma band power lasting up to five days after a single dose administration. These results demonstrate that ketamine has the potential to alter maladaptive neural responses in the ACC induced by chronic pain.
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Affiliation(s)
- Isabel D Friesner
- Department of Anesthesiology, Perioperative Care and Pain, New York University School of Medicine, New York, NY, 10016, USA
| | - Erik Martinez
- Department of Anesthesiology, Perioperative Care and Pain, New York University School of Medicine, New York, NY, 10016, USA
| | - Haocheng Zhou
- Department of Anesthesiology, Perioperative Care and Pain, New York University School of Medicine, New York, NY, 10016, USA
| | | | - Anna Li
- Department of Anesthesiology, Perioperative Care and Pain, New York University School of Medicine, New York, NY, 10016, USA
| | - Zhe Sage Chen
- Department of Psychiatry, New York University School of Medicine, New York, NY, 10016, USA.,Department of Neuroscience & Physiology, New York University School of Medicine, New York, NY, 10016, USA.,Neuroscience Institute, New York University School of Medicine, New York, NY, 10016, USA
| | - Qiaosheng Zhang
- Department of Anesthesiology, Perioperative Care and Pain, New York University School of Medicine, New York, NY, 10016, USA.
| | - Jing Wang
- Department of Anesthesiology, Perioperative Care and Pain, New York University School of Medicine, New York, NY, 10016, USA. .,Department of Neuroscience & Physiology, New York University School of Medicine, New York, NY, 10016, USA. .,Neuroscience Institute, New York University School of Medicine, New York, NY, 10016, USA.
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Mussio CA, Harte SE, Borszcz GS. Regional Differences Within the Anterior Cingulate Cortex in the Generation Versus Suppression of Pain Affect in Rats. THE JOURNAL OF PAIN 2019; 21:121-134. [PMID: 31201992 DOI: 10.1016/j.jpain.2019.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/22/2019] [Accepted: 06/02/2019] [Indexed: 01/08/2023]
Abstract
The anterior cingulate cortex (ACC) modulates emotional responses to pain. Whereas, the caudal ACC (cACC) promotes expression of pain affect, the rostral ACC (rACC) contributes to its suppression. Both subdivisions receive glutamatergic innervation, and the present study evaluated the contribution of N-methyl-d-aspartic acid (NMDA) receptors within these subdivisions to rats' expression of pain affect. Vocalizations that follow a brief noxious tail shock (vocalization afterdischarges, VAD) are a validated rodent model of pain affect. The threshold current for eliciting VAD was increased in a dose-dependent manner by injecting NMDA into the rACC, but performance (latency, amplitude, and duration) at threshold was not altered. Alternately, the threshold current for eliciting VAD was not altered following injection of NMDA into the cACC, but its amplitude and duration at threshold were increased in a dose-dependent manner. These effects were limited to Cg1 of the rACC and cACC, and blocked by pretreatment of the ACC with the NMDA receptor antagonist d-2-amino-5-phosphonovalerate. These findings demonstrate that NMDA receptor agonism within the cACC and rACC either increases or decreases emotional responses to noxious stimulation, respectively. PERSPECTIVE: NMDA receptor activation of the rostral and caudal ACC respectively inhibited or enhanced rats' emotional response to pain. These findings mirror those obtained from human neuroimaging studies; thereby, supporting the use of this model system in evaluating the contribution of ACC to pain affect.
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Affiliation(s)
- Casey A Mussio
- Behavioral and Cognitive Neuroscience Program, Department of Psychology, Wayne State University, Detroit, Michigan
| | - Steven E Harte
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | - George S Borszcz
- Behavioral and Cognitive Neuroscience Program, Department of Psychology, Wayne State University, Detroit, Michigan.
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Tsuda M, Koga K, Chen T, Zhuo M. Neuronal and microglial mechanisms for neuropathic pain in the spinal dorsal horn and anterior cingulate cortex. J Neurochem 2017; 141:486-498. [DOI: 10.1111/jnc.14001] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/02/2017] [Accepted: 02/08/2017] [Indexed: 01/02/2023]
Affiliation(s)
- Makoto Tsuda
- Department of Life Innovation; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Kohei Koga
- Department of Neurophysiology; Hirosaki University Graduate School of Medicine; Hirosaki Japan
- Department of Physiology; University of Toronto; Toronto Canada
| | - Tao Chen
- Department of Physiology; University of Toronto; Toronto Canada
- Department of Anatomy, Histology and Embryology; Fourth Military Medical University; Xi'an Shaanxi China
- Center for Neuron and Disease; Frontier Institutes of Science and Technology; Xi'an Jiaotong University; Xi'an Shanxi China
| | - Min Zhuo
- Department of Physiology; University of Toronto; Toronto Canada
- Center for Neuron and Disease; Frontier Institutes of Science and Technology; Xi'an Jiaotong University; Xi'an Shanxi China
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Gee LE, Walling I, Ramirez-Zamora A, Shin DS, Pilitsis JG. Subthalamic deep brain stimulation alters neuronal firing in canonical pain nuclei in a 6-hydroxydopamine lesioned rat model of Parkinson's disease. Exp Neurol 2016; 283:298-307. [PMID: 27373204 DOI: 10.1016/j.expneurol.2016.06.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/18/2016] [Accepted: 06/28/2016] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Chronic pain is one of the most common non-motor symptoms of Parkinson's disease (PD) affecting up to 85% of patients. Previous studies have established that reduced mechanical and thermal thresholds occur in both idiopathic PD patients and animal models of PD, suggesting that changes may occur in sensory processing circuits. Improvements in sensory thresholds are achieved using subthalamic nucleus (STN) deep brain stimulation (DBS), however the mechanism by which this occurs remains unresolved. MATERIALS AND METHODS We examined unilateral medial forebrain bundle 6-hydroxydopamine (6OHDA) rat model of PD to determine whether STN DBS alters neuronal firing rates in brain areas involved in ascending and descending pain processing. Specifically, single unit in vivo recordings were conducted in the anterior cingulate cortex (ACC), the periaqueductal grey (PAG), and the ventral posteriolateral nucleus of the thalamus (VPL), before, during and after stimulation was applied to the STN at 50 or 150Hz. RESULTS Sham and 6OHDA lesioned animals have similar neuronal firing activity in the VPL, ACC and PAG before stimulation was applied (p>0.05). In 6OHDA lesioned rats, both low frequency stimulation (LFS) (p<0.01) and high frequency stimulation (HFS) (p<0.05) attenuated firing frequency in the ACC. In shams, only LFS decreased firing frequency. A subset of neurons in the PAG was significantly attenuated in both sham and 6OHDA lesioned animals during HFS and LFS (p<0.05), while another subset of PAG neuronal activity significantly increased in 6OHDA lesioned rats during HFS (p<0.05). Finally, low or high frequency STN DBS did not alter neuronal firing frequencies in the VPL. CONCLUSIONS Our results suggest that STN DBS alters neuronal firing in descending pain circuits. We hypothesize that STN DBS attenuates excitatory projections from the ACC to the PAG in 6OHDA lesioned rats. Following this, neurons in the PAG respond by either increasing (during HFS only) or decreasing (during both LFS and HFS), which may modulate descending facilitation or inhibition at the level of the spinal cord. Future work should address specific neuronal changes in the ACC and PAG that occur in a freely moving parkinsonian animal during a pain stimulus treated with STN DBS.
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Affiliation(s)
- Lucy E Gee
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurosurgery, Albany Medical Center, Albany, NY, United States
| | - Ian Walling
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurosurgery, Albany Medical Center, Albany, NY, United States
| | | | - Damian S Shin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Julie G Pilitsis
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurosurgery, Albany Medical Center, Albany, NY, United States.
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Hamzeh-Gooshchi N, Tamaddonfard E, Farshid AA. Effects of microinjection of histamine into the anterior cingulate cortex on pain-related behaviors induced by formalin in rats. Pharmacol Rep 2015; 67:593-9. [DOI: 10.1016/j.pharep.2014.12.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/25/2014] [Accepted: 12/30/2014] [Indexed: 11/16/2022]
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Gu L, Uhelski ML, Anand S, Romero-Ortega M, Kim YT, Fuchs PN, Mohanty SK. Pain inhibition by optogenetic activation of specific anterior cingulate cortical neurons. PLoS One 2015; 10:e0117746. [PMID: 25714399 PMCID: PMC4340873 DOI: 10.1371/journal.pone.0117746] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 12/31/2014] [Indexed: 01/22/2023] Open
Abstract
Cumulative evidence from both humans and animals suggests that the anterior cingulate cortex (ACC) is important for pain-related perception, and thus a likely target for pain relief therapy. However, use of existing electrode based ACC stimulation has not significantly reduced pain, at least in part due to the lack of specificity and likely co-activation of both excitatory and inhibitory neurons. Herein, we report a dramatic reduction of pain behavior in transgenic mice by optogenetic stimulation of the inhibitory neural circuitry of the ACC expressing channelrhodopsin-2. Electrophysiological measurements confirmed that stimulation of ACC inhibitory neurons is associated with decreased neural activity in the ACC. Further, a distinct optogenetic stimulation intensity and frequency-dependent inhibition of spiking activity in the ACC was observed. Moreover, we confirmed specific electrophysiological responses from different neuronal units in the thalamus, in response to particular types of painful stimuli (i,e., formalin injection, pinch), which we found to be modulated by optogenetic control of the ACC inhibitory neurons. These results underscore the inhibition of the ACC as a clinical alternative in inhibiting chronic pain, and leads to a better understanding of the pain processing circuitry of the cingulate cortex.
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Affiliation(s)
- Ling Gu
- Biophysics and Physiology Group, Department of Physics, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Megan L. Uhelski
- Department of Psychology, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Sanjay Anand
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Mario Romero-Ortega
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Young-tae Kim
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Perry N. Fuchs
- Departments of Psychology and Biology, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Samarendra K. Mohanty
- Biophysics and Physiology Group, Department of Physics, University of Texas at Arlington, Arlington, TX-76019, United States of America
- * E-mail:
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Fuchs PN, Peng YB, Boyette-Davis JA, Uhelski ML. The anterior cingulate cortex and pain processing. Front Integr Neurosci 2014; 8:35. [PMID: 24829554 PMCID: PMC4017137 DOI: 10.3389/fnint.2014.00035] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 04/15/2014] [Indexed: 12/11/2022] Open
Abstract
The neural network that contributes to the suffering which accompanies persistent pain states involves a number of brain regions. Of primary interest is the contribution of the cingulate cortex in processing the affective component of pain. The purpose of this review is to summarize recent data obtained using novel behavioral paradigms in animals based on measuring escape and/or avoidance of a noxious stimulus. These paradigms have successfully been used to study the nature of the neuroanatomical and neurochemical contributions of the anterior cingulate cortex (ACC) to higher order pain processing in rodents.
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Affiliation(s)
- Perry N Fuchs
- Department of Psychology, University of Texas at Arlington, Arlington TX, USA ; Department of Biology, University of Texas at Arlington, Arlington TX, USA
| | - Yuan Bo Peng
- Department of Psychology, University of Texas at Arlington, Arlington TX, USA
| | | | - Megan L Uhelski
- Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis MN, USA
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Ikeda H, Takasu S, Murase K. Contribution of anterior cingulate cortex and descending pain inhibitory system to analgesic effect of lemon odor in mice. Mol Pain 2014; 10:14. [PMID: 24555533 PMCID: PMC3936890 DOI: 10.1186/1744-8069-10-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 01/13/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Affections are thought to regulate pain perception through the descending pain inhibitory system in the central nervous system. In this study, we examined in mice the affective change by inhalation of the lemon oil, which is well used for aromatherapy, and the effect of lemon odor on pain sensation. We also examined the anterior cingulate cortex (ACC) and descending pain inhibitory system to such regulation of pain. RESULTS In the elevated plus maze, the time spent in the open arms was increased by inhalation of lemon oil. The pain behavior induced by injection of formalin into the hind paw was decreased. By inhalation of lemon oil, the number of c-Fos expression by formalin injection was significantly increased in the ACC, periaqueductal grey (PAG), nucleu raphe magnus (NRM) and locus ceruleus, and decreased in the spinal dorsal horn (SDH). The destruction of the ACC with ibotenic acid led to prevent the decrease of formalin-evoked nocifensive behavior in mice exposed to lemon oil. In these mice, the change of formalin-induced c-Fos expression in the ACC, lateral PAG, NRM and SDH by lemon odor was also prevented. Antagonize of dopamine D1 receptor in the ACC prevented to the analgesic effect of lemon oil. CONCLUSIONS These results suggest that the analgesic effect of lemon oil is induced by dopamine-related activation of ACC and the descending pain inhibitory system.
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Affiliation(s)
- Hiroshi Ikeda
- Department of Human and Artificial Intelligence Systems, Graduate School of Engineering, and Research and Education Program for Life Science, University of Fukui, 3-9-1 Bunkyo, 910-8507 Fukui, Japan.
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