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Sullere S, Kunczt A, McGehee DS. A cholinergic circuit that relieves pain despite opioid tolerance. Neuron 2023; 111:3414-3434.e15. [PMID: 37734381 PMCID: PMC10843525 DOI: 10.1016/j.neuron.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/19/2023] [Accepted: 08/16/2023] [Indexed: 09/23/2023]
Abstract
Chronic pain is a tremendous burden for afflicted individuals and society. Although opioids effectively relieve pain, significant adverse outcomes limit their utility and efficacy. To investigate alternate pain control mechanisms, we explored cholinergic signaling in the ventrolateral periaqueductal gray (vlPAG), a critical nexus for descending pain modulation. Biosensor assays revealed that pain states decreased acetylcholine release in vlPAG. Activation of cholinergic projections from the pedunculopontine tegmentum to vlPAG relieved pain, even in opioid-tolerant conditions, through ⍺7 nicotinic acetylcholine receptors (nAChRs). Activating ⍺7 nAChRs with agonists or stimulating endogenous acetylcholine inhibited vlPAG neuronal activity through Ca2+ and peroxisome proliferator-activated receptor α (PPAR⍺)-dependent signaling. In vivo 2-photon imaging revealed that chronic pain induces aberrant excitability of vlPAG neuronal ensembles and that ⍺7 nAChR-mediated inhibition of these cells relieves pain, even after opioid tolerance. Finally, pain relief through these cholinergic mechanisms was not associated with tolerance, reward, or withdrawal symptoms, highlighting its potential clinical relevance.
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Affiliation(s)
- Shivang Sullere
- Committee on Neurobiology, University of Chicago, Chicago, IL 60637, USA
| | - Alissa Kunczt
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL 60637, USA
| | - Daniel S McGehee
- Committee on Neurobiology, University of Chicago, Chicago, IL 60637, USA; Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL 60637, USA.
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2
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Uliana DL, Diniz CRAF, da Silva LA, Borges-Assis AB, Lisboa SF, Resstel LBM. Contextual fear expression engages a complex set of interactions between ventromedial prefrontal cortex cholinergic, glutamatergic, nitrergic and cannabinergic signaling. Neuropharmacology 2023; 232:109538. [PMID: 37024011 DOI: 10.1016/j.neuropharm.2023.109538] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/22/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023]
Abstract
Rats re-exposed to an environment previously associated with the onset of shocks evoke a set of conditioned defensive responses in preparation to an eventual flight or fight reaction. Ventromedial prefrontal cortex (vmPFC) is mutually important for controlling the behavioral/physiological consequences of stress exposure and the one's ability to satisfactorily undergo spatial navigation. While cholinergic, cannabinergic and glutamatergic/nitrergic neurotransmissions within the vmPFC are shown as important for modulating both behavioral and autonomic defensive responses, there is a gap on how these systems would interact to ultimately coordinate such conditioned reactions. Then, males Wistar rats had guide cannulas bilaterally implanted to allow drugs to be administered in vmPFC 10 min before their re-exposure to the conditioning chamber where three shocks were delivered at the intensity of 0.85 mA for 2 s two days ago. A femoral catheter was implanted for cardiovascular recordings the day before fear retrieval test. It was found that the increment of freezing behavior and autonomic responses induced by vmPFC infusion of neostigmine (acetylcholinesterase inhibitor) were prevented by prior infusion of a transient receptor potential vanilloid type 1 (TRPV1) antagonist, N-methyl-d-aspartate receptor antagonist, neuronal nitric oxide synthase inhibitor, nitric oxide scavenger and soluble guanylate cyclase inhibitor. A type 3 muscarinic receptor antagonist was unable to prevent the boosting in conditioned responses triggered by a TRPV1 agonist and a cannabinoid receptors type 1 antagonist. Altogether, our results suggest that expression of contextual conditioned responses involves a complex set of signaling steps comprising different but complementary neurotransmitter pathways.
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Affiliation(s)
- Daniela Lescano Uliana
- Department of Pharmacology, School of Medicine, Campus USP, Ribeirão Preto, SP, 14049-900, Brazil
| | | | - Leandro Antero da Silva
- Department of Pharmacology, School of Medicine, Campus USP, Ribeirão Preto, SP, 14049-900, Brazil
| | | | - Sabrina Francesca Lisboa
- Department of Pharmacology, School of Medicine, Campus USP, Ribeirão Preto, SP, 14049-900, Brazil; Department of Biomolecular Sciences, School of Pharmaceutical Sciences, Campus USP, Ribeirão Preto, SP, 14040-9034, Brazil; National Institute of Science and Technology for Translational Medicine, Brazilian National Council for Scientific and Technological Development, Brasília, Brazil.
| | - Leonardo Barbosa Moraes Resstel
- Department of Pharmacology, School of Medicine, Campus USP, Ribeirão Preto, SP, 14049-900, Brazil; National Institute of Science and Technology for Translational Medicine, Brazilian National Council for Scientific and Technological Development, Brasília, Brazil.
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3
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Kan HW, Peng WH, Wu CC, Wang DW, Lee MT, Lee YK, Chu TH, Ho YC. Rapid antidepressant-like effects of muscarinic receptor antagonists require BDNF-dependent signaling in the ventrolateral periaqueductal gray. Psychopharmacology (Berl) 2022; 239:3805-3818. [PMID: 36221037 DOI: 10.1007/s00213-022-06250-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/26/2022] [Indexed: 10/17/2022]
Abstract
RATIONALE Clinical reports reveal that scopolamine, an acetylcholine muscarinic receptor antagonist, exerts rapid antidepressant effects in depressed patients, but the mechanisms underlying the therapeutic effects have not been fully identified. OBJECTIVES The present study examines the cellular mechanisms by which scopolamine produces antidepressant-like effects through its action in the ventrolateral midbrain periaqueductal gray (vlPAG). METHODS We used a well-established mouse model of depression induced by chronic restraint stress (CRS) exposure for 14 days. Behaviors were tested using the forced swim test (FST), tail suspension test (TST), female urine sniffing test (FUST), novelty-suppressed feeding test (NSFT), and locomotor activity (LMA). Synaptic transmission in the vlPAG was measured by whole-cell patch-clamp recordings. IntravlPAG microinjection was used to pharmacologically verify the signaling cascades of scopolamine in the vlPAG. RESULTS The results demonstrated that intraperitoneal injection of scopolamine produced antidepressant-like effects in a dose-dependent manner without affecting locomotor activity. CRS elicited depression-like behaviors, whereas intraperitoneal injection of scopolamine alleviated CRS-induced depression-like behaviors. CRS diminished glutamatergic transmission in the vlPAG, while scopolamine reversed the above effects. Moreover, intravlPAG microinjection of the L-type voltage-dependent calcium channel (VDCC) blocker verapamil, tropomyosin-related kinase B (TrkB) receptor antagonist ANA-12, mammalian target of rapamycin complex 1 (mTORC1) inhibitor rapamycin, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA) antagonist CNQX prevented scopolamine-induced antidepressant-like effects. CONCLUSIONS Scopolamine ameliorated CRS-elicited depression-like behavior required activation of VDCC, resulting in activity-dependent release of brain-derived neurotrophic factor (BDNF), engaging the TrkB receptor and downstream mTORC1 signaling in the vlPAG.
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Affiliation(s)
- Hung-Wei Kan
- School of Medicine for International Students, College of Medicine, I-Shou University, Kaohsiung City, 82445, Taiwan, Republic of China
| | - Wei-Hao Peng
- School of Medicine for International Students, College of Medicine, I-Shou University, Kaohsiung City, 82445, Taiwan, Republic of China.,School of Medicine, National Tsing Hua University, Hsinchu, 300044, Taiwan, Republic of China
| | - Cheng-Chun Wu
- School of Medicine, College of Medicine, I-Shou University, No.8, Yida Rd., Yanchao District, Kaohsiung City, 82445, Taiwan, Republic of China
| | - Deng-Wu Wang
- School of Medicine, College of Medicine, I-Shou University, No.8, Yida Rd., Yanchao District, Kaohsiung City, 82445, Taiwan, Republic of China.,Department of Psychiatry, E-Da Hospital, Kaohsiung City, 82445, Taiwan, Republic of China
| | - Ming Tatt Lee
- Faculty of Pharmaceutical Sciences, UCSI University, 56000, Cheras, Kuala Lumpur, Malaysia
| | - Yung-Kuo Lee
- Medical Laboratory, Medical Education and Research Center, Kaohsiung Armed Forces General Hospital, Kaohsiung City, 80284, Taiwan, Republic of China
| | - Tian-Huei Chu
- Medical Laboratory, Medical Education and Research Center, Kaohsiung Armed Forces General Hospital, Kaohsiung City, 80284, Taiwan, Republic of China
| | - Yu-Cheng Ho
- School of Medicine, College of Medicine, I-Shou University, No.8, Yida Rd., Yanchao District, Kaohsiung City, 82445, Taiwan, Republic of China.
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Neural Subtype-dependent Cholinergic Modulation of Neural Activities by Activation of Muscarinic 2 Receptors and G Protein-activated Inwardly Rectifying Potassium Channel in Rat Periaqueductal Gray Neurons. Neuroscience 2022; 506:1-13. [PMID: 36270414 DOI: 10.1016/j.neuroscience.2022.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/06/2022] [Accepted: 10/12/2022] [Indexed: 11/05/2022]
Abstract
Acetylcholine plays a pivotal role in the regulation of functions such as pain and the sleep and wake cycle by modulating neural activities of the ventrolateral periaqueductal gray (vlPAG). Electrophysiological studies have shown that cholinergic effects are inconsistent among recorded neurons, particularly in the depolarization and hyperpolarization of the resting membrane potential (RMP). This discrepancy may be due to the neural subtype-dependent cholinergic modulation of the RMP. To examine this possibility, we performed whole-cell patch-clamp recordings from subtype-identified neurons using vesicular GABA transporter (VGAT)-Venus × ChAT-TdTomato rats and elucidated cellular mechanisms of cholinergic effects on the RMP. The application of carbachol hyperpolarized the RMP of cholinergic neurons in a dose-dependent manner but had much less of an effect on other neural subtypes, including GABAergic/glycinergic and glutamatergic neurons. Cholinergic hyperpolarization was accompanied by a decrease in input resistance. These cholinergic effects were blocked by AF-DX384 or gallamine and were mimicked by arecaidine but-2-ynyl ester tosylate, suggesting that the carbachol-induced hyperpolarization of the RMP in cholinergic neurons is mediated via M2 receptors. Tertiapin suppressed the carbachol-induced G protein-activated inwardly rectifying potassium channel (GIRK) currents and hyperpolarization of the RMP in cholinergic neurons. Intracellular application of GDP-β-S blocked the carbachol-induced hyperpolarization of the RMP. Neostigmine slowly hyperpolarized the RMP in cholinergic neurons. These results suggest that neural firing of vlPAG cholinergic neurons is suppressed by GIRK currents induced via M2 receptor activation, and this negative feedback regulation of cholinergic neuronal activities can be induced by acetylcholine, which is intrinsically released in the vlPAG.
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Scienza-Martin K, Lotz FN, Zanona QK, Santana-Kragelund F, Crestani AP, Boos FZ, Calcagnotto ME, Quillfeldt JA. Memory consolidation depends on endogenous hippocampal levels of anandamide: CB1 and M4, but possibly not TRPV1 receptors mediate AM404 effects. Neuroscience 2022; 497:53-72. [DOI: 10.1016/j.neuroscience.2022.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/14/2022] [Accepted: 04/08/2022] [Indexed: 11/15/2022]
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Winters BL, Vaughan CW. Mechanisms of endocannabinoid control of synaptic plasticity. Neuropharmacology 2021; 197:108736. [PMID: 34343612 DOI: 10.1016/j.neuropharm.2021.108736] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/13/2023]
Abstract
The endogenous cannabinoid transmitter system regulates synaptic transmission throughout the nervous system. Unlike conventional transmitters, specific stimuli induce synthesis of endocannabinoids (eCBs) in the postsynaptic neuron, and these travel backwards to modulate presynaptic inputs. In doing so, eCBs can induce short-term changes in synaptic strength and longer-term plasticity. While this eCB regulation is near ubiquitous, it displays major regional and synapse specific variations with different synapse specific forms of short-versus long-term plasticity throughout the brain. These differences are due to the plethora of pre- and postsynaptic mechanisms which have been implicated in eCB signalling, the intricacies of which are only just being realised. In this review, we shall describe the current understanding and highlight new advances in this area, with a focus on the retrograde action of eCBs at CB1 receptors (CB1Rs).
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Affiliation(s)
- Bryony Laura Winters
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia.
| | - Christopher Walter Vaughan
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia
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Bouchet CA, Ingram SL. Cannabinoids in the descending pain modulatory circuit: Role in inflammation. Pharmacol Ther 2020; 209:107495. [PMID: 32004514 PMCID: PMC7183429 DOI: 10.1016/j.pharmthera.2020.107495] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/17/2020] [Indexed: 01/09/2023]
Abstract
The legalization of cannabis in some states has intensified interest in the potential for cannabis and its constituents to lead to novel therapeutics for pain. Our understanding of the cellular mechanisms underlying cannabinoid actions in the brain have lagged behind opioids; however, the current opioid epidemic has also increased attention on the use of cannabinoids as alternatives to opioids for pain, especially chronic pain that requires long-term use. Endogenous cannabinoids are lipid signaling molecules that have complex roles in modulating neuronal function throughout the brain. In this review, we discuss cannabinoid functions in the descending pain modulatory pathway, a brain circuit that integrates cognitive and emotional processing of pain to modulate incoming sensory inputs. In addition, we highlight areas where further studies are necessary to understand cannabinoid regulation of descending pain modulation.
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Affiliation(s)
- Courtney A Bouchet
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States of America
| | - Susan L Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States of America.
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Scuteri D, Rombolá L, Tridico L, Mizoguchi H, Watanabe C, Sakurada T, Sakurada S, Corasaniti MT, Bagetta G, Morrone LA. Neuropharmacological Properties of the Essential Oil of Bergamot for the Clinical Management of Pain-Related BPSDs. Curr Med Chem 2019. [PMID: 29521195 DOI: 10.2174/0929867325666180307115546] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Alzheimer's Disease (AD) accounts for approximately 50% of all cases of dementia and, in spite of the great effort for the development of disease-modifying drugs, a definitive treatment of cognitive impairment is not available yet. A perfect adherence to the current therapy of cognitive decline is needed for a better control of the disease and this is proven to reduce, though not completely abolish, the associated Behavioural and Psychological Symptoms of Dementia (BPSDs) from occurring. This cluster of symptoms, remarkably affecting patients' health-related quality of life (HRQL), is tightly associated with pain states. Antipsychotics are the only treatment for BPSDs. However, these drugs are more effective and safer in the short-term (6-12 weeks), they are able to manage aggression but not agitation and they cannot control pain. Aromatherapy with Melissa officinalis and Lavandula officinalis has been employed to handle BPSDs, but it has not provided strong evidence to offer relief from pain. OBJECTIVE Bergamot Essential Oil (BEO) exerts antinociceptive activity through several pharmacological mechanisms: in particular, it is able to enhance autophagy, a process undergoing derangement in chronic pain. Thus, the sound pharmacological basis for clinical translation of aromatherapy with BEO in the treatment of BPSDs has been pointed out. CONCLUSION The antinociceptive effects elicited by BEO in experimental pain models make it a possible candidate for the pharmacological management of pain-related BPSDs.
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Affiliation(s)
- Damiana Scuteri
- Department of Pharmacy, Health Science and Nutrition, Section of Translational Pharmacology, University of Calabria, 87036 Rende (CS), Italy
| | - Laura Rombolá
- Department of Pharmacy, Health Science and Nutrition, Section of Translational Pharmacology, University of Calabria, 87036 Rende (CS), Italy
| | - Laura Tridico
- Department of Pharmacy, Health Science and Nutrition, Section of Translational Pharmacology, University of Calabria, 87036 Rende (CS), Italy
| | - Hirokazu Mizoguchi
- Department of Physiology and Anatomy, Tohoku Pharmaceutical University, Sendai, Japan
| | - Chizuko Watanabe
- Department of Physiology and Anatomy, Tohoku Pharmaceutical University, Sendai, Japan
| | - Tsukasa Sakurada
- Department of Physiology and Anatomy, Tohoku Pharmaceutical University, Sendai, Japan
| | - Shinobu Sakurada
- First Department of Pharmacology, Daiichi College of Pharmaceutical Sciences, Fukuoka, Japan
| | - Maria T Corasaniti
- Department of Health Science, University Magna Graecia, Catanzaro, Italy
| | - Giacinto Bagetta
- Department of Pharmacy, Health Science and Nutrition, Section of Translational Pharmacology, University of Calabria, 87036 Rende (CS), Italy
| | - Luigi A Morrone
- Department of Pharmacy, Health Science and Nutrition, Section of Translational Pharmacology, University of Calabria, 87036 Rende (CS), Italy
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9
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Sokolov AY, Murzina AA, Osipchuk AV, Lyubashina OA, Amelin AV. Cholinergic mechanisms of headaches. NEUROCHEM J+ 2017. [DOI: 10.1134/s1819712417020131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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10
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Gawel K, Gibula-Bruzda E, Dziedzic M, Jenda-Wojtanowska M, Marszalek-Grabska M, Silberring J, Kotlinska JH. Cholinergic activation affects the acute and chronic antinociceptive effects of morphine. Physiol Behav 2016; 169:22-32. [PMID: 27865771 DOI: 10.1016/j.physbeh.2016.11.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 11/05/2016] [Accepted: 11/05/2016] [Indexed: 12/24/2022]
Abstract
Current studies indicate that the cholinergic and opioid systems interact to modulate pain. In the present work, we investigated the influence of the cholinesterase inhibitors, donepezil (0.5; 1 or 3mg/kg, i.p.) and rivastigmine (0.03; 0.5 or 1mg/kg, i.p.), on the acute antinociceptive effects of morphine (5mg/kg, i.p.) in the hot plate test in mice. Herein, both inhibitors were found to enhance and prolong the analgesic effects of morphine without affecting latencies themselves. In an extension of this work, we determined which cholinergic receptors subtype mediates the enhancement of analgesic effects of morphine, following inhibition of cholinesterases. In this part of the study, scopolamine (0.5mg/kg, i.p.), a muscarinic cholinergic receptors antagonist, but not mecamylamine (3mg/kg, i.p.), a nicotinic cholinergic receptors antagonist, reversed the enhancing effects of donepezil (3mg/kg, i.p.) and rivastigmine (1mg/kg, i.p.) on the morphine antinociception. Moreover, both cholinesterase inhibitors attenuated the development of tolerance to the antinociceptive effects of morphine. In contrast, acute administration of donepezil (3mg/kg, i.p.) or rivastigmine (1mg/kg, i.p.) on the day of expression of tolerance, had no effect on the already developed morphine tolerance. What is more, in both set of experiments, rivastigmine was slightly more potent than donepezil due to the broader inhibitory spectrum of this drug on acetylcholine degradation. Thus, our results suggest that the cholinesterase inhibitors, donepezil and rivastigmine, may be administered with morphine in order to enhance the latter's analgesic effects for the treatment of acute and chronic pain.
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Affiliation(s)
- Kinga Gawel
- Department of Pharmacology and Pharmacodynamics, Medical University, Chodzki 4a, 20-093 Lublin, Poland; Department of Experimental and Clinical Pharmacology, Medical University, Jaczewskiego 8b, 20-090 Lublin, Poland
| | - Ewa Gibula-Bruzda
- Department of Pharmacology and Pharmacodynamics, Medical University, Chodzki 4a, 20-093 Lublin, Poland
| | - Marcin Dziedzic
- Department of Laboratory Diagnostic, Medical University, Chodzki 1, 20-093 Lublin, Poland
| | | | - Marta Marszalek-Grabska
- Department of Pharmacology and Pharmacodynamics, Medical University, Chodzki 4a, 20-093 Lublin, Poland
| | - Jerzy Silberring
- Department of Biochemistry and Neurobiology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland
| | - Jolanta H Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Chodzki 4a, 20-093 Lublin, Poland.
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Fogaça MV, Fedoce AG, Ferreira-Junior NC, Guimarães FS, Resstel LB. Involvement of M1 and CB₁ receptors in the anxiogenic-like effects induced by neostigmine injected into the rat prelimbic medial prefrontal cortex. Psychopharmacology (Berl) 2016; 233:1377-85. [PMID: 26873081 DOI: 10.1007/s00213-016-4228-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 01/31/2016] [Indexed: 11/30/2022]
Abstract
The prelimbic (PL) medial prefrontal cortex is a brain region highly involved in the control of emotional responses, being modulated by several neurotransmitter systems, including the cholinergic and endocannabinoid. Activation of muscarinic type 1 (M1) receptors in the brain induces retrograde suppression of inhibition through the induction of endocannabinoid release, which, in turn, activates cannabinoid type 1 (CB1) receptors. No study so far, however, has been conducted to investigate if the cholinergic and endocannabinoid systems interact in the PL to modulate anxiety-related behaviors. Thus, the present work aimed at verifying if intra-PL administration of neostigmine, an acetylcholinesterase inhibitor, would produce changes in anxiety-like behavior and if these effects are mediated by M1 and CB1 receptor activation. Independent groups of animals received bilateral injections of vehicle, the M1 receptor antagonist pirenzepine (0.06, 0.6, and 6 nmol), the CB1 receptor antagonist AM251 (0.1 nmol), or the fatty acid amide hydrolase (FAAH) enzyme inhibitor URB597 (1, 3, and 10 pmol), followed by vehicle or neostigmine (0.01, 0.1, and 1 nmol), and were submitted to the elevated plus-maze (EPM) test. Neostigmine (1 nmol) decreased open arm exploration of the maze. This anxiogenic-like effect was reproduced in another anxiety-related animal model, the light-dark box. Previous injection of pirenzepine or AM251 abolished this response in the EPM, whereas URB597 had no effect. These results suggest that CB1 and M1 receptors interact in the PL to control anxiety-like behaviors.
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Affiliation(s)
- M V Fogaça
- Department of Pharmacology, Medical School of Ribeirão Preto-University of São Paulo (FMRP-USP), 3900 Bandeirantes Avenue, Monte Alegre, Ribeirão Preto, SP, Brazil, 14049-900. .,Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), University of São Paulo (USP), Ribeirão Preto, Brazil.
| | - A G Fedoce
- Department of Pharmacology, Medical School of Ribeirão Preto-University of São Paulo (FMRP-USP), 3900 Bandeirantes Avenue, Monte Alegre, Ribeirão Preto, SP, Brazil, 14049-900.,Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), University of São Paulo (USP), Ribeirão Preto, Brazil
| | - N C Ferreira-Junior
- Department of Pharmacology, Medical School of Ribeirão Preto-University of São Paulo (FMRP-USP), 3900 Bandeirantes Avenue, Monte Alegre, Ribeirão Preto, SP, Brazil, 14049-900.,Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), University of São Paulo (USP), Ribeirão Preto, Brazil
| | - F S Guimarães
- Department of Pharmacology, Medical School of Ribeirão Preto-University of São Paulo (FMRP-USP), 3900 Bandeirantes Avenue, Monte Alegre, Ribeirão Preto, SP, Brazil, 14049-900.,Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), University of São Paulo (USP), Ribeirão Preto, Brazil
| | - L B Resstel
- Department of Pharmacology, Medical School of Ribeirão Preto-University of São Paulo (FMRP-USP), 3900 Bandeirantes Avenue, Monte Alegre, Ribeirão Preto, SP, Brazil, 14049-900. .,Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), University of São Paulo (USP), Ribeirão Preto, Brazil.
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Hernández-Martínez R, Aceves JJ, Rueda-Orozco PE, Hernández-Flores T, Hernández-González O, Tapia D, Galarraga E, Bargas J. Muscarinic presynaptic modulation in GABAergic pallidal synapses of the rat. J Neurophysiol 2015; 113:796-807. [DOI: 10.1152/jn.00385.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The external globus pallidus (GPe) is central for basal ganglia processing. It expresses muscarinic cholinergic receptors and receives cholinergic afferents from the pedunculopontine nuclei (PPN) and other regions. The role of these receptors and afferents is unknown. Muscarinic M1-type receptors are expressed by synapses from striatal projection neurons (SPNs). Because axons from SPNs project to the GPe, one hypothesis is that striatopallidal GABAergic terminals may be modulated by M1 receptors. Alternatively, some M1 receptors may be postsynaptic in some pallidal neurons. Evidence of muscarinic modulation in any of these elements would suggest that cholinergic afferents from the PPN, or other sources, could modulate the function of the GPe. In this study, we show this evidence using striatopallidal slice preparations: after field stimulation in the striatum, the cholinergic muscarinic receptor agonist muscarine significantly reduced the amplitude of inhibitory postsynaptic currents (IPSCs) from synapses that exhibited short-term synaptic facilitation. This inhibition was associated with significant increases in paired-pulse facilitation, and quantal content was proportional to IPSC amplitude. These actions were blocked by atropine, pirenzepine, and mamba toxin-7, suggesting that receptors involved were M1. In addition, we found that some pallidal neurons have functional postsynaptic M1 receptors. Moreover, some evoked IPSCs exhibited short-term depression and a different kind of modulation: they were indirectly modulated by muscarine via the activation of presynaptic cannabinoid CB1 receptors. Thus pallidal synapses presenting distinct forms of short-term plasticity were modulated differently.
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Affiliation(s)
- Ricardo Hernández-Martínez
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - José J. Aceves
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Pavel E. Rueda-Orozco
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Teresa Hernández-Flores
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Omar Hernández-González
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Dagoberto Tapia
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Elvira Galarraga
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - José Bargas
- Instituto de Fisiología Celular, División de Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Zhang Y, Yu T, Liu Y, Qian K, Yu BW. Muscarinic M1 Receptors Regulate Propofol Modulation of GABAergic Transmission in Rat Ventrolateral Preoptic Neurons. J Mol Neurosci 2014; 55:830-5. [DOI: 10.1007/s12031-014-0435-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 09/30/2014] [Indexed: 11/25/2022]
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14
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Hu SSJ, Ho YC, Chiou LC. No more pain upon Gq-protein-coupled receptor activation: role of endocannabinoids. Eur J Neurosci 2014; 39:467-84. [PMID: 24494686 DOI: 10.1111/ejn.12475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 01/24/2023]
Abstract
Marijuana has been used to relieve pain for centuries. The analgesic mechanism of its constituents, the cannabinoids, was only revealed after the discovery of cannabinoid receptors (CB1 and CB2) two decades ago. The subsequent identification of the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), and their biosynthetic and degradation enzymes discloses the therapeutic potential of compounds targeting the endocannabinoid system for pain control. Inhibitors of the anandamide and 2-AG degradation enzymes, fatty acid amide hydrolase and monoacylglycerol lipase, respectively, may be superior to direct cannabinoid receptor ligands as endocannabinoids are synthesized on demand and rapidly degraded, focusing action at generating sites. Recently, a promising strategy for pain relief was revealed in the periaqueductal gray (PAG). It is initiated by Gq-protein-coupled receptor (Gq PCR) activation of the phospholipase C-diacylglycerol lipase enzymatic cascade, generating 2-AG that produces inhibition of GABAergic transmission (disinhibition) in the PAG, thereby leading to analgesia. Here, we introduce the antinociceptive properties of exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, particularly in the PAG. We also review recent studies disclosing the Gq PCR-phospholipase C-diacylglycerol lipase-2-AG retrograde disinhibition mechanism in the PAG, induced by activating several Gq PCRs, including metabotropic glutamatergic (type 5 metabotropic glutamate receptor), muscarinic acetylcholine (M1/M3), and orexin 1 receptors. Disinhibition mediated by type 5 metabotropic glutamate receptor can be initiated by glutamate transporter inhibitors or indirectly by substance P, neurotensin, cholecystokinin and capsaicin. Finally, the putative role of 2-AG generated after activating the above neurotransmitter receptors in stress-induced analgesia is discussed.
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Affiliation(s)
- Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
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15
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Lau BK, Drew GM, Mitchell VA, Vaughan CW. Endocannabinoid modulation by FAAH and monoacylglycerol lipase within the analgesic circuitry of the periaqueductal grey. Br J Pharmacol 2014; 171:5225-36. [PMID: 25041240 DOI: 10.1111/bph.12839] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 06/19/2014] [Accepted: 06/27/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Endogenous cannabinoids (endocannabinoids) in the periaqueductal grey (PAG) play a vital role in mediating stress-induced analgesia. This analgesic effect of endocannabinoids is enhanced by pharmacological inhibition of their degradative enzymes. However, the specific effects of endocannabinoids and the inhibitors of their degradation are largely unknown within this pain-modulating region. EXPERIMENTAL APPROACH In vitro electrophysiological recordings were conducted from PAG neurons in rat midbrain slices. The effects of the major endocannabinoids and their degradation inhibitors on inhibitory GABAergic synaptic transmission were examined. KEY RESULTS Exogenous application of the endocannabinoid, anandamide (AEA), but not 2-arachidonoylglycerol (2-AG), produced a reduction in inhibitory GABAergic transmission in PAG neurons. This AEA-induced suppression of inhibition was enhanced by the fatty acid amide hydrolase (FAAH) inhibitor, URB597, whereas a 2-AG-induced suppression of inhibition was unmasked by the monoacylglycerol lipase (MGL) inhibitor, JZL184. In addition, application of the CB1 receptor antagonist, AM251, facilitated the basal GABAergic transmission in the presence of URB597 and JZL184, which was further enhanced by the dual FAAH/MGL inhibitor, JZL195. CONCLUSIONS AND IMPLICATIONS Our results indicate that AEA and 2-AG act via disinhibition within the PAG, a cellular action consistent with analgesia. These actions of AEA and 2-AG are tightly regulated by their respective degradative enzymes, FAAH and MGL. Furthermore, individual or combined inhibition of FAAH and/or MGL enhanced tonic disinhibition within the PAG. Therefore, the current findings support the therapeutic potential of FAAH and MGL inhibitors as a novel pharmacotherapy for pain.
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Affiliation(s)
- Benjamin K Lau
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
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16
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Hescham S, Temel Y, Casaca-Carreira J, Arslantas K, Yakkioui Y, Blokland A, Jahanshahi A. A neuroanatomical analysis of the effects of a memory impairing dose of scopolamine in the rat brain using cytochrome c oxidase as principle marker. J Chem Neuroanat 2014; 59-60:1-7. [PMID: 24768696 DOI: 10.1016/j.jchemneu.2014.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 04/08/2014] [Accepted: 04/10/2014] [Indexed: 12/13/2022]
Abstract
Acetylcholine plays a role in mnemonic and attentional processes, but also in locomotor and anxiety-related behavior. Receptor blockage by scopolamine can therefore induce cognitive as well as motor deficits and increase anxiety levels. Here we show that scopolamine, at a dose that has previously been found to affect learning and memory performance (0.1 mg/kg i.p.), has a widespread effect on cytochrome c oxidase histochemistry in various regions of the rat brain. We found a down-regulation of cytochrome c oxidase in the nucleus basalis, in movement-related structures such as the primary motor cortex and the globus pallidus, memory-related structures such as the CA1 subfield of the hippocampus and perirhinal cortex and in anxiety-related structures like the amygdala, which also plays a role in memory. However choline acetyltransferase levels were only affected in the CA1 subfield of the hippocampus and both, choline acetyltransferase and c-Fos expression levels were decreased in the amygdala. These findings corroborate strong cognitive behavioral effects of this drug, but also suggest possible anxiety- and locomotor-related changes in subjects. Moreover, they present histochemical evidence that the effects of scopolamine are not ultimately restricted to cognitive parameters.
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Affiliation(s)
- Sarah Hescham
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands; European Graduate School of Neuroscience (Euron), The Netherlands.
| | - Yasin Temel
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands; Department of Neurosurgery, Maastricht University, Maastricht, The Netherlands; European Graduate School of Neuroscience (Euron), The Netherlands
| | - João Casaca-Carreira
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands; European Graduate School of Neuroscience (Euron), The Netherlands
| | - Kemal Arslantas
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Youssef Yakkioui
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands; Department of Neurosurgery, Maastricht University, Maastricht, The Netherlands; European Graduate School of Neuroscience (Euron), The Netherlands
| | - Arjan Blokland
- Department of Neuropsychology and Psychopharmacology, University of Maastricht, The Netherlands; European Graduate School of Neuroscience (Euron), The Netherlands
| | - Ali Jahanshahi
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands; Department of Neurosurgery, Maastricht University, Maastricht, The Netherlands; European Graduate School of Neuroscience (Euron), The Netherlands.
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Ramikie TS, Nyilas R, Bluett RJ, Gamble-George JC, Hartley ND, Mackie K, Watanabe M, Katona I, Patel S. Multiple mechanistically distinct modes of endocannabinoid mobilization at central amygdala glutamatergic synapses. Neuron 2014; 81:1111-1125. [PMID: 24607231 PMCID: PMC3955008 DOI: 10.1016/j.neuron.2014.01.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2013] [Indexed: 11/26/2022]
Abstract
The central amygdala (CeA) is a key structure at the limbic-motor interface regulating stress responses and emotional learning. Endocannabinoid (eCB) signaling is heavily implicated in the regulation of stress-response physiology and emotional learning processes; however, the role of eCBs in the modulation of synaptic efficacy in the CeA is not well understood. Here we describe the subcellular localization of CB1 cannabinoid receptors and eCB synthetic machinery at glutamatergic synapses in the CeA and find that CeA neurons exhibit multiple mechanistically and temporally distinct modes of postsynaptic eCB mobilization. These data identify a prominent role for eCBs in the modulation of excitatory drive to CeA neurons and provide insight into the mechanisms by which eCB signaling and exogenous cannabinoids could regulate stress responses and emotional learning.
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Affiliation(s)
- Teniel S Ramikie
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37212, USA; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Rita Nyilas
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Rebecca J Bluett
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37212, USA; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Joyonna C Gamble-George
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37212, USA; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Nolan D Hartley
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Ken Mackie
- Gill Institute and Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - István Katona
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Sachin Patel
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37212, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37212, USA; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37212, USA.
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18
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Chiou LC, Hu SSJ, Ho YC. Targeting the cannabinoid system for pain relief? ACTA ACUST UNITED AC 2013; 51:161-70. [PMID: 24529672 DOI: 10.1016/j.aat.2013.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/11/2013] [Indexed: 12/15/2022]
Abstract
Marijuana has been used to relieve pain for centuries, but its analgesic mechanism has only been understood during the past two decades. It is mainly mediated by its constituents, cannabinoids, through activating central cannabinoid 1 (CB1) receptors, as well as peripheral CB1 and CB2 receptors. CB2-selective agonists have the benefit of lacking CB1 receptor-mediated CNS side effects. Anandamide and 2-arachidonoylglycerol (2-AG) are two intensively studied endogenous lipid ligands of cannabinoid receptors, termed endocannabinoids, which are synthesized on demand and rapidly degraded. Thus, inhibitors of their degradation enzymes, fatty acid amide hydrolase and monoacylglycerol lipase (MAGL), respectively, may be superior to direct cannabinoid receptor ligands as a promising strategy for pain relief. In addition to the antinociceptive properties of exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, we also review recent studies that revealed a novel analgesic mechanism, involving 2-AG in the periaqueductal gray (PAG), a midbrain region for initiating descending pain inhibition. It is initiated by Gq-protein-coupled receptor (GqPCR) activation of the phospholipase C (PLC)-diacylglycerol lipase (DAGL) enzymatic cascade, generating 2-AG that produces inhibition of GABAergic transmission (disinhibition) in the PAG, thereby leading to analgesia. This GqPCR-PLC-DAGL-2-AG retrograde disinhibition mechanism in the PAG can be initiated by activating type 5 metabotropic glutamate receptor (mGluR5), muscarinic acetylcholine (M1/M3), and orexin (OX1) receptors. mGluR5-mediated disinhibition can be initiated by glutamate transporter inhibitors, or indirectly by substance P, neurotensin, cholecystokinin, capsaicin, and AM404, the bioactive metabolite of acetaminophen in the brain. The putative role of 2-AG generated after activating the above neurotransmitter receptors in stress-induced analgesia is also discussed.
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Affiliation(s)
- Lih-Chu Chiou
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacology, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan.
| | - Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Cheng Ho
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
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19
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Jeong SG, Choi IS, Cho JH, Jang IS. Cholinergic modulation of primary afferent glutamatergic transmission in rat medullary dorsal horn neurons. Neuropharmacology 2013; 75:295-303. [DOI: 10.1016/j.neuropharm.2013.07.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/28/2013] [Accepted: 07/22/2013] [Indexed: 10/26/2022]
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20
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Lauterbach EC, Cummings JL, Kuppuswamy PS. Toward a more precise, clinically—informed pathophysiology of pathological laughing and crying. Neurosci Biobehav Rev 2013; 37:1893-916. [PMID: 23518269 DOI: 10.1016/j.neubiorev.2013.03.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 03/01/2013] [Accepted: 03/11/2013] [Indexed: 12/11/2022]
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Damasceno F, Skinner GO, Araújo PC, Ferraz MMD, Tenório F, de Almeida OMMS. Nitric oxide modulates the hyperalgesic response to mechanical noxious stimuli in sleep-deprived rats. BMC Neurosci 2013; 14:92. [PMID: 23987566 PMCID: PMC3765713 DOI: 10.1186/1471-2202-14-92] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 08/22/2013] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Sleep restriction alters pain perception in animals and humans, and many studies have indicated that paradoxical sleep deprivation (PSD) promotes hyperalgesia. The hyperalgesia observed after mechanical nociceptive stimulus is reversed through nitric oxide synthase (NOS) inhibition. Both nitric oxide (NO) and the dorsolateral periaqueductal gray matter (dlPAG) area of the brainstem are involved in hyperalgesia. Thus, in this work, we investigated the pain-related behavior response after mechanical noxious stimuli (electronic von Frey test), and the activity of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), an indicator of NOS activity, within the dlPAG of paradoxical sleep-deprived rats. We also evaluated the effects of pre-treatment with L-NAME on these parameters. RESULTS These data revealed that PSD reduced the hindpaw withdrawal threshold (-47%, p < 0.0001) confirming the hyperalgesic effect of this condition. In addition, there were more NADPH-d positive cells in dlPAG after PSD than in control rats (+ 59%, p < 0.0001). L-NAME treatment prevented the reduction in the hindpaw withdrawal threshold (+ 93%, p < 0.0001) and the increase in the NADPH-d positive cells number in the dlPAG of PSD-treated rats (-36%, p < 0.0001). CONCLUSION These data suggest that the hyperalgesic response to mechanical noxious stimuli in paradoxical sleep-deprived rats is associated with increased NOS activity in the dlPAG, which presumably influences the descending antinociceptive pathway.
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Affiliation(s)
- Fabio Damasceno
- Department of Pharmacology and Psychobiology, Institute of Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil
| | - Gabriela O Skinner
- Department of Pharmacology and Psychobiology, Institute of Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil
| | - Paulo C Araújo
- Department of Pharmacology and Psychobiology, Institute of Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil
| | - Marcia MD Ferraz
- Department of Pharmacology and Psychobiology, Institute of Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil
| | - Frank Tenório
- Department of Pharmacology and Psychobiology, Institute of Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil
| | - Olga MMS de Almeida
- Department of Pharmacology and Psychobiology, Institute of Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil
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22
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Romano MR, Lograno MD. Signaling cross-talk between cannabinoid and muscarinic systems actives Rho-kinase and increases the contractile responses of the bovine ciliary muscle. Eur J Pharmacol 2013; 702:174-9. [PMID: 23396229 DOI: 10.1016/j.ejphar.2013.01.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 01/02/2013] [Accepted: 01/29/2013] [Indexed: 11/16/2022]
Abstract
The aim of the present study was to evaluate the role of a possible interaction between cannabinoid and muscarinic systems, both widely expressed in the ocular structure and involved in the control of bovine ciliary muscle contractility and intraocular pressure modulation. The ciliary muscle strips isolated by bovine eyes were exposed cumulatively to anandamide in the presence and in the absence of carbachol (5 nM), in a miograph system for isometric recording. The experiments were also conducted in the presence of AM251 (100 nM), 4-DAMP (100 nM), Pertussis toxin (500 ng/ml), U73122 (0.1 and 1 μM), chelerythrine (1 and 10 μM) and Y27632 (1 and 10 μM). Contractile responses were expressed as the percentage of 10 μM carbachol-induced contraction. The anandamide-induced contraction on bovine ciliary muscle strips was enhanced by the previous stimulation of Gq-protein-coupled muscarinic M3 receptors with carbachol. The contractile response to anandamide plus carbachol was affected by different inhibitors such as Pertussis toxin, phospholipase C, protein kinase C and Rho-kinase. The key results of the present study show that sequential activation of muscarinic M3 receptors and cannabinoid CB1 receptors produce synergistic contractile effects of the bovine ciliary muscle by involving the activation of Rho-kinase and protein kinase C.
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Affiliation(s)
- Maria Rosaria Romano
- Department of Pharmacy - Science of Drug, Section of Pharmacology and Toxicology, University of Bari Aldo Moro, Bari, Italy.
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23
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Muscarinic M4 receptors regulate GABAergic transmission in rat tuberomammillary nucleus neurons. Neuropharmacology 2012; 63:936-44. [PMID: 22828639 DOI: 10.1016/j.neuropharm.2012.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/30/2012] [Accepted: 07/03/2012] [Indexed: 11/22/2022]
Abstract
Histaminergic neurons within the tuberomammillary nucleus (TMN) play an important role in sleep-wakefulness regulation. Here, we report the muscarinic modulation of GABAergic spontaneous miniature inhibitory postsynaptic currents (mIPSCs) in mechanically dissociated rat histaminergic neurons using a conventional whole-cell patch clamp technique. Muscarine, a nonselective muscarinic acetylcholine (mACh) receptor agonist, reversibly decreased mIPSC frequency without affecting the current amplitude, indicating that muscarine acts presynaptically to decrease the probability of spontaneous GABA release. The muscarine action on GABAergic mIPSC frequency was completely blocked by atropine, a nonselective mACh receptor antagonist, and tropicamide, an M(4) receptor antagonist. The muscarine-induced decrease in mIPSC frequency was completely occluded in the presence of Cd(2+), a general voltage-dependent Ca(2+) channel blocker, or in a Ca(2+)-free external solution. However, pharmacological agents affecting adenylyl cyclase or G-protein coupled inwardly rectifying K(+) channel activity did not prevent the inhibitory action of muscarine on GABAergic mIPSCs. These results suggest that muscarine acts on M(4) receptors on GABAergic nerve terminals projecting to histaminergic neurons to inhibit spontaneous GABA release via the inhibition of Ca(2+) influx from the extracellular space. Muscarine also inhibited action potential-dependent GABA release by activating presynaptic M(4) receptors in more physiological conditions. The M(4) receptor-mediated modulation of GABAergic transmission onto TMN neurons may contribute to the regulation of sleep-wakefulness.
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Gyombolai P, Pap D, Turu G, Catt KJ, Bagdy G, Hunyady L. Regulation of endocannabinoid release by G proteins: a paracrine mechanism of G protein-coupled receptor action. Mol Cell Endocrinol 2012; 353:29-36. [PMID: 22075205 PMCID: PMC4169275 DOI: 10.1016/j.mce.2011.10.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 10/12/2011] [Accepted: 10/12/2011] [Indexed: 02/06/2023]
Abstract
In the past years, the relationship between the endocannabinoid system (ECS) and other hormonal and neuromodulatory systems has been intensively studied. G protein-coupled receptors (GPCRs) can stimulate endocannabinoid (eCB) production via activation of G(q/11) proteins and, in some cases, G(s) proteins. In this review, we summarize the pathways through which GPCR activation can trigger eCB release, as well as the best known examples of this process throughout the body tissues. Angiotensin II-induced activation of AT(1) receptors, similar to other G(q/11)-coupled receptors, can lead to the formation of 2-arachidonoylglycerol (2-AG), an important eCB. The importance of eCB formation in angiotensin II action is supported by the finding that the hypertensive effect of angiotensin II, injected directly into the hypothalamic paraventricular nucleus of anaesthetized rats, can be abolished by AM251, an inverse agonist of CB(1) cannabinoid receptors (CB(1)Rs). We conclude that activation of the ECS should be considered as a general consequence of the stimulation of G(q/11)-coupled receptors, and may mediate some of the physiological effects of GPCRs.
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Affiliation(s)
- Pál Gyombolai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Dorottya Pap
- Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
| | - Gábor Turu
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Kevin J. Catt
- Section on Hormonal Regulation, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - György Bagdy
- Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
- Group of Neuropsychopharmacology and Neurochemistry, Semmelweis University and Hungarian Academy of Sciences, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- Laboratory of Neurobiochemistry and Molecular Physiology, Semmelweis University and Hungarian Academy of Sciences, Budapest, Hungary
- Corresponding author at: Department of Physiology, Faculty of Medicine, Semmelweis University, H-1444 Budapest, P.O. Box 259, Hungary. Tel: +36 1 266 9180; fax: +36 1 266 6504
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Activation of orexin 1 receptors in the periaqueductal gray of male rats leads to antinociception via retrograde endocannabinoid (2-arachidonoylglycerol)-induced disinhibition. J Neurosci 2011; 31:14600-10. [PMID: 21994376 DOI: 10.1523/jneurosci.2671-11.2011] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Orexin A and B are hypothalamic peptides known to modulate arousal, feeding, and reward via OX1 and OX2 receptors. Orexins are also antinociceptive in the brain, but their mechanism(s) of action remain unclear. Here, we investigated the antinociceptive mechanism of orexin A in the rat ventrolateral periaqueductal gray (vlPAG), a midbrain region crucial for initiating descending pain inhibition. In vlPAG slices, orexin A (30-300 nm) depressed GABAergic evoked IPSCs. This effect was blocked by an OX1 [1-(2-methylbenzoxazol-6-yl)-3-[1,5]naphthyridin-4-yl urea (SB 334867)], but not OX2 [N-acyl 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (compound 29)], antagonist. Orexin A increased the paired-pulse ratio of paired IPSCs and decreased the frequency, but not amplitude, of miniature IPSCs. Orexin A-induced IPSC depression was mimicked by (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-napthalenylmethanone (WIN 55,212-2), a cannabinoid 1 (CB1) receptor agonist. 1-(2,4-Dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-(1-piperidyl)pyrazole-3-carboxamide (AM 251), a CB1 antagonist, reversed depressant effects by both agonists. Orexin A-induced IPSC depression was prevented by 1-[6-[[(17β)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122) and tetrahydrolipstatin, inhibitors of phospholipase C (PLC) and diacylglycerol lipase (DAGL), respectively, and enhanced by cyclohexyl[1,1'-biphenyl]-3-ylcarbamate (URB602), which inhibits enzymatic degradation of 2-arachidonoylglycerol (2-AG). Moderate DAGLα, but not DAGLβ, immunoreactivity was observed in the vlPAG. Orexin A produced an overall excitatory effect on evoked postsynaptic potentials and hence increased vlPAG neuronal activity. Intra-vlPAG microinjection of orexin A reduced hot-plate nociceptive responses in rats in a manner blocked by SB 334867 and AM 251. Therefore, orexin A may produce antinociception by activating postsynaptic OX1 receptors, stimulating synthesis of 2-AG, an endocannabinoid, through a Gq-protein-mediated PLC-DAGLα enzymatic cascade culminating in retrograde inhibition of GABA release (disinhibition) in the vlPAG.
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Kawahara H, Drew GM, Christie MJ, Vaughan CW. Inhibition of fatty acid amide hydrolase unmasks CB1 receptor and TRPV1 channel-mediated modulation of glutamatergic synaptic transmission in midbrain periaqueductal grey. Br J Pharmacol 2011; 163:1214-22. [PMID: 21175570 DOI: 10.1111/j.1476-5381.2010.01157.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE While arachidonyl ethanolamine (anandamide) produces pharmacological effects mediated by cannabinoid CB1 receptors, it is also an agonist at the transient receptor potential vanilloid type 1 (TRPV1) ion channel. This study examined the cellular actions of anandamide in the midbrain periaqueductal grey (PAG), a region implicated in the analgesic actions of cannabinoids, and which expresses both CB1 receptors and TRPV1. EXPERIMENTAL APPROACH In vitro whole cell patch clamp recordings of glutamatergic excitatory postsynaptic currents (EPSCs) were made from rat and mouse PAG slices. KEY RESULTS Capsaicin (1 µM) increased the rate, but not the amplitude of miniature EPSCs in subpopulations of neurons throughout the rat and mouse PAG. Capsaicin had no effect on miniature EPSCs in PAG neurons from TRPV1 knock-out mice. In mouse PAG neurons, anandamide (30 µM) had no effect on the rate of miniature EPSCs alone, or in the presence of either the CB1 antagonist AM251 (3 µM) or the TRPV1 antagonist iodoresiniferatoxin (300 nM). Anandamide produced a decrease in miniature EPSC rate in the presence of the fatty acid amide hydrolase (FAAH) inhibitor URB597 (1 µM). By contrast, anandamide produced an increase in miniature EPSC rate in the presence of both URB597 and AM251, which was absent in TRPV1 knock-out mice. CONCLUSIONS AND IMPLICATIONS These results suggest that the actions of anandamide within PAG are limited by enzymatic degradation by FAAH. FAAH blockade unmasks both presynaptic inhibition and excitation of glutamatergic synaptic transmission which are mediated via CB1 receptors and TRPV1 respectively.
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Affiliation(s)
- H Kawahara
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia.
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Liao HT, Lee HJ, Ho YC, Chiou LC. Capsaicin in the periaqueductal gray induces analgesia via metabotropic glutamate receptor-mediated endocannabinoid retrograde disinhibition. Br J Pharmacol 2011; 163:330-45. [PMID: 21232043 DOI: 10.1111/j.1476-5381.2011.01214.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Capsaicin, an agonist of transient receptor potential vanilloid 1 (TRPV1) channels, is pro-nociceptive in the periphery but is anti-nociceptive when administered into the ventrolateral periaqueductal gray (vlPAG), a midbrain region for initiating descending pain inhibition. Here, we investigated how activation of TRPV1 channels in the vlPAG leads to anti-nociception. EXPERIMENTAL APPROACH We examined synaptic transmission and neuronal activity using whole-cell recordings in vlPAG slices in vitro and hot-plate nociceptive responses in rats after drug microinjection into the vlPAG in vivo. KEY RESULTS Capsaicin (1-10 µM) depressed evoked GABAergic inhibitory postsynaptic currents (eIPSCs) in vlPAG slices presynaptically, while increasing miniature excitatory PSC frequency. Capsaicin-induced eIPSC depression was antagonized by cannabinoid CB₁ and metabotropic glutamate (mGlu₅) receptor antagonists, and prevented by inhibiting diacylglycerol lipase (DAGL), which converts DAG into 2-arachidonoylglycerol (2-AG), an endocannabinoid. Capsaicin induced membrane depolarization in 2/3 neurons recorded but, overall, increased neuronal firings by increasing evoked postsynaptic potentials. Intra-vlPAG capsaicin reduced hot-plate responses in rats, effects blocked by CB₁ and mGlu receptor antagonists. Effects of capsaicin were antagonized by SB 366791, a TRPV1 channel antagonist. CONCLUSIONS AND IMPLICATIONS Capsaicin activated TRPV1s on glutamatergic terminals to release glutamate which activated postsynaptic mGlu₅ receptors, yielding 2-AG from DAG by DAGL hydrolysis. 2-AG induces retrograde inhibition (disinhibition) of GABA release via presynaptic CB₁ receptors. This disinhibition in the vlPAG leads to anti-nociception by activating the descending pain inhibitory pathway. This is a novel TRPV1 channel-mediated anti-nociceptive mechanism in the brain and a new interaction between vanilloid and endocannabinoid systems.
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Affiliation(s)
- H-T Liao
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Mitchell VA, Jeong HJ, Drew GM, Vaughan CW. Cholecystokinin exerts an effect via the endocannabinoid system to inhibit GABAergic transmission in midbrain periaqueductal gray. Neuropsychopharmacology 2011; 36:1801-10. [PMID: 21525858 PMCID: PMC3154098 DOI: 10.1038/npp.2011.59] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cholecystokinin modulates pain and anxiety via its functions within brain regions such as the midbrain periaqueductal gray (PAG). The aim of this study was to examine the cellular actions of cholecystokinin on PAG neurons. Whole-cell patch clamp recordings were made from rat midbrain PAG slices in vitro to examine the postsynaptic effects of cholecystokinin and its effects on synaptic transmission. Sulfated cholecystokinin-(26-33) (CCK-S, 100-300 nM), but not non-sulfated cholecystokinin-(26-33) (CCK-NS, 100-300 nM) produced an inward current in a sub-population of opioid sensitive and insensitive PAG neurons, which did not reverse over a range of membrane potentials. The CCK-S-induced current was abolished by the CCK1 selective antagonist devazepide (100 nM), but not by the CCK2 selective antagonists CI988 (100 nM, 1 μM) and LY225910 (1 μM). CCK-S, but not CCK-NS produced a reduction in the amplitude of evoked GABA(A)-mediated inhibitory postsynaptic currents (IPSCs) and an increase in the evoked IPSC paired-pulse ratio. By contrast, CCK-S had little effect on the rate and amplitude of TTX-resistant miniature IPSCs under basal conditions and when external K(+) was elevated. The CCK-S-induced inhibition of evoked IPSCs was abolished by the cannabinoid CB1 receptor antagonist AM251 (3 μM), the mGluR5 antagonist MPEP (10 μM) and the 1, 2-diacylglycerol lipase (DAGLα) inhibitor tetrahydrolipstatin (10 μM). In addition, CCK-S produced an increase in the rate of spontaneous non-NMDA-mediated, TTX-dependent excitatory postsynaptic currents (EPSCs). These results suggest that cholecystokinin produces direct neuronal depolarisation via CCK1 receptors and inhibits GABAergic synaptic transmission via action potential-dependent release of glutamate and mGluR5-induced endocannabinoid signaling. Thus, cholecystokinin has cellular actions within the PAG that can both oppose and reinforce opioid and cannabinoid modulation of pain and anxiety within this brain structure.
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Affiliation(s)
- Vanessa A Mitchell
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Hyo-Jin Jeong
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Geoffrey M Drew
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Christopher W Vaughan
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia,Pain Management Research Institute, Level 13, Kolling Building, Kolling Institute for Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia, Tel: +61 29 926 4950, Fax: +61 29 926 7659, E-mail: , http://www.pmri.med.usyd.edu.au
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Mojtahedin A, Tamaddonfard E, Zanbouri A. Role of central muscarinic cholinergic receptors in the formalin-induced pain in rats. Indian J Pharmacol 2011; 41:144-7. [PMID: 20442824 PMCID: PMC2861817 DOI: 10.4103/0253-7613.55205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 02/20/2009] [Accepted: 06/08/2009] [Indexed: 11/23/2022] Open
Abstract
Objectives: In the present study, central effects of physostigmine and atropine have investigated in the formalin-induced pain in rats. Materials and Methods: In conscious rats implanted with an intracerebroventricular (i.c.v.) cannula, the effects of i.c.v. injection of physostigmine and atropine were investigated on the formalin test in the rat. Formalin test was induced by subcutaneous (s.c.) injection of formalin (50 μl, 1%) in ventral surface of left hind paw, and durations of licking and biting of the injected paw were measured in 5-min blocks for 1 h. Results: Formalin produced a biphasic response (first phase: 0–5 and second phase: 15–40 min) in durations of licking and biting of the injected paw. Physostigmine at doses of 2.5, 5 and 10 ug significantly (P < 0.05) attenuated both first and second phases of pain response. Atropine (5 and 10 ug), used alone, produced no significant effect on pain, but pretreatment with atropine (10 ug) significantly (P < 0.05) blocked antinociception induced by physostigmine (5 ug). Conclusion: These results indicate that i.c.v. physostigmine can affect both neurogenic and inflammatory phases of formalin-induced pain through a mechanism in which the muscarinic cholinergic receptors are involved.
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Affiliation(s)
- Ali Mojtahedin
- Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
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Tamaddonfard E, Hamzeh-Gooshchi N. Effects of subcutaneous and intracerebroventricular injection of physostigmine on the acute corneal nociception in rats. Pharmacol Rep 2011; 62:858-63. [PMID: 21098868 DOI: 10.1016/s1734-1140(10)70345-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/13/2010] [Indexed: 10/25/2022]
Abstract
The present study investigated the effects of subcutaneous (sc) and intracerebroventricular (icv) injections of physostigmine (a cholinesterase inhibitor), atropine (an antagonist of muscarinic cholinergic receptors) and hexamethonium (an antagonist of nicotinic cholinergic receptors) on the acute corneal nociception in rats. Local application of 5 M NaCl solution on the corneal surface of the eye produced a significant nociceptive behavior, characterized by eye wiping. The number of eye wipes was counted during the first 30 s. The sc (0.25, 0.5 and 1 mg/kg) and icv (1.25, 2.5, 5 and 10 μg) injections of physostigmine significantly (p < 0.05) decreased the number of eye wipes. Atropine and hexamethonium at (2 mg/kg, sc and 20 μg, icv) had no effects when used alone, however, atropine, but not hexamethonium prevented the antinociception induced by physostigmine (sc and icv). The results of this study indicate that the central muscarinic, but not nicotinic receptors might be involved in the antinociceptive effect of physostigmine in the acute corneal model of pain in rats.
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Affiliation(s)
- Esmaeal Tamaddonfard
- Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 57153-1177, Iran.
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Nakamura M, Jang IS. Presynaptic nicotinic acetylcholine receptors enhance GABAergic synaptic transmission in rat periaqueductal gray neurons. Eur J Pharmacol 2010; 640:178-84. [DOI: 10.1016/j.ejphar.2010.04.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 03/30/2010] [Accepted: 04/24/2010] [Indexed: 01/16/2023]
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Heinricher MM, Martenson ME, Nalwalk JW, Hough LB. Neural basis for improgan antinociception. Neuroscience 2010; 169:1414-20. [PMID: 20570607 DOI: 10.1016/j.neuroscience.2010.05.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 05/14/2010] [Accepted: 05/17/2010] [Indexed: 11/25/2022]
Abstract
Improgan, the prototype compound of a novel class of non-opioid analgesic drugs derived from histamine antagonists, attenuates thermal and mechanical nociception in rodents following intracerebroventricular (i.c.v.) administration. Improgan does not bind to known opioid, histamine or cannabinoid receptors, and its molecular target has not been identified. It is known however, that improgan acts directly in the periaqueductal gray and the rostral ventromedial medulla to produce its antinociceptive effects, and that inactivation of the rostral ventromedial medulla prevents the antinociceptive effect of improgan given i.c.v. Here we used in vivo single-cell recording in lightly anesthetized rats to show that improgan engages pain-modulating neurons in the medulla to produce antinociception. Following improgan administration, OFF-cells, which inhibit nociception, became continuously active and no longer paused during noxious stimulation. The increase in OFF-cell firing does not represent a non-specific neuroexcitant effect of this drug, since ON-cell discharge, associated with net nociceptive facilitation, was depressed. NEUTRAL-cell firing was unaffected by improgan. The net response of rostral ventromedial medulla (RVM) neurons to improgan is thus comparable to that evoked by mu-opioids and cannabinoids, well known RVM-active analgesic drugs. This common basis for improgan, opioid, and cannabinoid antinociception in the RVM supports the idea that improgan functions as a specific analgesic agent.
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Affiliation(s)
- M M Heinricher
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR 97239, USA.
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33
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Mitchell VA, Kawahara H, Vaughan CW. Neurotensin inhibition of GABAergic transmission via mGluR-induced endocannabinoid signalling in rat periaqueductal grey. J Physiol 2009; 587:2511-20. [PMID: 19359367 DOI: 10.1113/jphysiol.2008.167429] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Neurotensin modulates pain via its actions within descending analgesic pathways which include brain regions such as the midbrain periaqueductal grey (PAG). The aim of this study was to examine the cellular actions of neurotensin on PAG neurons. Whole cell patch clamp recordings were made from rat midbrain PAG slices in vitro to examine the postsynaptic effects of neurotensin and its effects on GABA(A) mediated inhibitory postsynaptic currents (IPSCs). Neurotensin (100-300 nM) produced an inward current in subpopulations of opioid sensitive and insensitive PAG neurons which did not reverse over membrane potentials between -50 and -130 mV. The neurotensin induced current was abolished by the NTS1 and NTS1/2 antagonists SR48692 (300 nM) and SR142948A (300 nM). Neurotensin also produced a reduction in the amplitude of evoked IPSCs, but had no effect on the rate and amplitude of TTX-resistant miniature IPSCs. The neurotensin induced inhibition of evoked IPSCs was reduced by the mGluR5 antagonist MPEP (5microM) and abolished by the cannabinoid CB(1) receptor antagonist AM251 (3 microM). These results suggest that neurotensin produces direct neuronal depolarisation via NTS1 receptors and inhibits GABAergic synaptic transmission within the PAG. The inhibition of synaptic transmission is mediated by neuronal excitation and action potential dependent release of glutamate, leading to mGluR5 mediated production of endocannabinoids which activate presynaptic CB(1) receptors. Thus, neurotensin has cellular actions within the PAG which are consistent with both algesic and analgesic activity, some of which are mediated via the endocannabinoid system.
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Affiliation(s)
- V A Mitchell
- Pain Management Research Institute, Northern Clinical School, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
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Kano M, Ohno-Shosaku T, Hashimotodani Y, Uchigashima M, Watanabe M. Endocannabinoid-mediated control of synaptic transmission. Physiol Rev 2009; 89:309-80. [PMID: 19126760 DOI: 10.1152/physrev.00019.2008] [Citation(s) in RCA: 1048] [Impact Index Per Article: 69.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The discovery of cannabinoid receptors and subsequent identification of their endogenous ligands (endocannabinoids) in early 1990s have greatly accelerated research on cannabinoid actions in the brain. Then, the discovery in 2001 that endocannabinoids mediate retrograde synaptic signaling has opened up a new era for cannabinoid research and also established a new concept how diffusible messengers modulate synaptic efficacy and neural activity. The last 7 years have witnessed remarkable advances in our understanding of the endocannabinoid system. It is now well accepted that endocannabinoids are released from postsynaptic neurons, activate presynaptic cannabinoid CB(1) receptors, and cause transient and long-lasting reduction of neurotransmitter release. In this review, we aim to integrate our current understanding of functions of the endocannabinoid system, especially focusing on the control of synaptic transmission in the brain. We summarize recent electrophysiological studies carried out on synapses of various brain regions and discuss how synaptic transmission is regulated by endocannabinoid signaling. Then we refer to recent anatomical studies on subcellular distribution of the molecules involved in endocannabinoid signaling and discuss how these signaling molecules are arranged around synapses. In addition, we make a brief overview of studies on cannabinoid receptors and their intracellular signaling, biochemical studies on endocannabinoid metabolism, and behavioral studies on the roles of the endocannabinoid system in various aspects of neural functions.
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Affiliation(s)
- Masanobu Kano
- Department of Neurophysiology, The University of Tokyo, Tokyo, Japan.
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