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Zeng ML, Xu W. A Narrative Review of the Published Pre-Clinical Evaluations: Multiple Effects of Arachidonic Acid, its Metabolic Enzymes and Metabolites in Epilepsy. Mol Neurobiol 2024:10.1007/s12035-024-04274-6. [PMID: 38842673 DOI: 10.1007/s12035-024-04274-6] [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: 12/11/2023] [Accepted: 05/29/2024] [Indexed: 06/07/2024]
Abstract
Arachidonic acid (AA), an important polyunsaturated fatty acid in the brain, is hydrolyzed by a direct action of phospholipase A2 (PLA2) or through the combined action of phospholipase C and diacylglycerol lipase, and released into the cytoplasm. Various derivatives of AA can be synthesized mainly through the cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 (P450) enzyme pathways. AA and its metabolic enzymes and metabolites play important roles in a variety of neurophysiological activities. The abnormal metabolites and their catalytic enzymes in the AA cascade are related to the pathogenesis of various central nervous system (CNS) diseases, including epilepsy. Here, we systematically reviewed literatures in PubMed about the latest randomized controlled trials, animal studies and clinical studies concerning the known features of AA, its metabolic enzymes and metabolites, and their roles in epilepsy. The exclusion criteria include non-original studies and articles not in English.
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Affiliation(s)
- Meng-Liu Zeng
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Wei Xu
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
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Cherry AL, Wheeler MJ, Mathisova K, Di Miceli M. In silico analyses of the involvement of GPR55, CB1R and TRPV1: response to THC, contribution to temporal lobe epilepsy, structural modeling and updated evolution. Front Neuroinform 2024; 18:1294939. [PMID: 38404644 PMCID: PMC10894036 DOI: 10.3389/fninf.2024.1294939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/19/2024] [Indexed: 02/27/2024] Open
Abstract
Introduction The endocannabinoid (eCB) system is named after the discovery that endogenous cannabinoids bind to the same receptors as the phytochemical compounds found in Cannabis. While endogenous cannabinoids include anandamide (AEA) and 2-arachidonoylglycerol (2-AG), exogenous phytocannabinoids include Δ-9 tetrahydrocannabinol (THC) and cannabidiol (CBD). These compounds finely tune neurotransmission following synapse activation, via retrograde signaling that activates cannabinoid receptor 1 (CB1R) and/or transient receptor potential cation channel subfamily V member 1 (TRPV1). Recently, the eCB system has been linked to several neurological diseases, such as neuro-ocular abnormalities, pain insensitivity, migraine, epilepsy, addiction and neurodevelopmental disorders. In the current study, we aim to: (i) highlight a potential link between the eCB system and neurological disorders, (ii) assess if THC exposure alters the expression of eCB-related genes, and (iii) identify evolutionary-conserved residues in CB1R or TRPV1 in light of their function. Methods To address this, we used several bioinformatic approaches, such as transcriptomic (Gene Expression Omnibus), protein-protein (STRING), phylogenic (BLASTP, MEGA) and structural (Phyre2, AutoDock, Vina, PyMol) analyzes. Results Using RNA sequencing datasets, we did not observe any dysregulation of eCB-related transcripts in major depressive disorders, bipolar disorder or schizophrenia in the anterior cingulate cortex, nucleus accumbens or dorsolateral striatum. Following in vivo THC exposure in adolescent mice, GPR55 was significantly upregulated in neurons from the ventral tegmental area, while other transcripts involved in the eCB system were not affected by THC exposure. Our results also suggest that THC likely induces neuroinflammation following in vitro application on mice microglia. Significant downregulation of TPRV1 occurred in the hippocampi of mice in which a model of temporal lobe epilepsy was induced, confirming previous observations. In addition, several transcriptomic dysregulations were observed in neurons of both epileptic mice and humans, which included transcripts involved in neuronal death. When scanning known interactions for transcripts involved in the eCB system (n = 12), we observed branching between the eCB system and neurophysiology, including proteins involved in the dopaminergic system. Our protein phylogenic analyzes revealed that CB1R forms a clade with CB2R, which is distinct from related paralogues such as sphingosine-1-phosphate, receptors, lysophosphatidic acid receptors and melanocortin receptors. As expected, several conserved residues were identified, which are crucial for CB1R receptor function. The anandamide-binding pocket seems to have appeared later in evolution. Similar results were observed for TRPV1, with conserved residues involved in receptor activation. Conclusion The current study found that GPR55 is upregulated in neurons following THC exposure, while TRPV1 is downregulated in temporal lobe epilepsy. Caution is advised when interpreting the present results, as we have employed secondary analyzes. Common ancestors for CB1R and TRPV1 diverged from jawless vertebrates during the late Ordovician, 450 million years ago. Conserved residues are identified, which mediate crucial receptor functions.
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Affiliation(s)
- Amy L. Cherry
- Worcester Biomedical Research Group, School of Science and the Environment, University of Worcester, Worcester, United Kingdom
| | - Michael J. Wheeler
- Sustainable Environments Research Group, School of Science and the Environment University of Worcester, Worcester, United Kingdom
| | - Karolina Mathisova
- School of Science and the Environment University of Worcester, Worcester, United Kingdom
| | - Mathieu Di Miceli
- Worcester Biomedical Research Group, School of Science and the Environment, University of Worcester, Worcester, United Kingdom
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Ye W, Xing J, Yu Z, Hu X, Zhao Y. Mechanism and treatments of antipsychotic-induced weight gain. Int J Obes (Lond) 2023; 47:423-433. [PMID: 36959286 DOI: 10.1038/s41366-023-01291-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/25/2023]
Abstract
The long-term use of antipsychotics (APs) may cause a variety of diseases, such as metabolic syndrome, antipsychotic-induced weight gain (AIWG), and even obesity. This paper reviews the various mechanisms of AIWG and obesity in detail, involving genetics, the central nervous system, the neuroendocrine system, and the gut microbiome. The common drug and non-drug therapies used in clinical practice are also introduced, providing the basis for research on the molecular mechanisms and the future selection of treatments.
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Affiliation(s)
- Wujie Ye
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Jingyu Xing
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zekai Yu
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Xingang Hu
- Internal encephalopathy of traditional Chinese medicine, Dongfang Hospital of Beijing University of Chinese Medicine, Beijing, 100078, China.
| | - Yan Zhao
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China.
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Kodirov SA, Bonni K, Wehrmeister M, Lutz B. Depolarization-initiated endogenous cannabinoid release and underlying retrograde neurotransmission in interneurons of amygdala. ACTA ACUST UNITED AC 2021; 28:44-52. [PMID: 33452114 PMCID: PMC7812861 DOI: 10.1101/lm.052555.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 10/13/2020] [Indexed: 12/19/2022]
Abstract
The depolarization is also important for the short-term synaptic plasticity, known as depolarization-induced suppression of excitation (DSE). The two major types of neurons and their synapses in the lateral nucleus of amygdala (LA) are prone to plasticity. However, DSE in interneurons has not been reported in amygdala in general and in LA in particular. Therefore, we conducted the patch-clamp experiments with LA interneurons. These neurons were identified by lack of adaptation in firing rate of action potentials. In this study, we show for the first time a transient suppression of neurotransmission at synapses both within the local network and between cortical inputs and interneurons of the LA. The retrograde neurotransmission from GABAergic interneurons were comparable with that of glutamatergic pyramidal cells. That is the axonal terminals of cortical inputs do not posses selectivity toward two neuronal subtypes. However, the DSE of both types of neurons involve an increase in intracellular Ca2+ and the release of endogenous cannabinoids (eCB) and activation of presynaptic CB1 receptors. The magnitude of DSE was significantly higher in interneurons compared with pyramidal cells, though developed with some latency.
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Affiliation(s)
- Sodikdjon A Kodirov
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, 55099 Mainz, Germany.,Center for Biomedical Studies, Department of Biological Sciences, University of Texas at Brownsville, Texas 78520, USA
| | - Kathrin Bonni
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, 55099 Mainz, Germany
| | - Michael Wehrmeister
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, 55099 Mainz, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry and Pathobiochemistry, University Medical Center Mainz, 55099 Mainz, Germany
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Abstract
Epilepsy is a chronic disease characterized by recurrent unprovoked seizures. Up to 30% of children with epilepsy will be refractory to standard anticonvulsant therapy, and those with epileptic encephalopathy can be particularly challenging to treat. The endocannabinoid system can modulate the physiologic processes underlying epileptogenesis. The anticonvulsant properties of several cannabinoids, namely Δ-tetrahydrocannabinol and cannabidiol (CBD), have been demonstrated in both in vitro and in vivo studies. Cannabis-based therapies have been used for millennia to treat a variety of diseases including epilepsy. Several studies have shown that CBD, both in isolation as a pharmaceutical-grade preparation or as part of a CBD-enriched cannabis herbal extract, is beneficial in decreasing seizure frequency in children with treatment-resistant epilepsy. Overall, cannabis herbal extracts appear to provide greater efficacy in decreasing seizure frequency, but the studies assessing cannabis herbal extract are either retrospective or small-scale observational studies. The two large randomized controlled studies assessing the efficacy of pharmaceutical-grade CBD in children with Dravet and Lennox-Gastaut syndromes showed similar efficacy to other anticonvulsants. Lack of data regarding appropriate dosing and pediatric pharmacokinetics continues to make authorization of cannabis-based therapies to children with treatment-resistant epilepsy challenging.
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Rodrigues de Oliveira F, Eleuterio Rodrigues K, Hamoy M, Rodrigues Sarquis Í, Otake Hamoy A, Elena Crespo Lopez M, Maciel Ferreira I, de Matos Macchi B, Luiz Martins do Nascimento J. Fatty Acid Amides Synthesized from Andiroba Oil ( Carapa guianensis Aublet.) Exhibit Anticonvulsant Action with Modulation on GABA-A Receptor in Mice: A Putative Therapeutic Option. Pharmaceuticals (Basel) 2020; 13:ph13030043. [PMID: 32164340 PMCID: PMC7151664 DOI: 10.3390/ph13030043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 12/17/2022] Open
Abstract
Epilepsy is a chronic neurological disease characterized by excessive neuronal activity leading to seizure; about 30% of affected patients suffer from the refractory and pharmacoresistant form of the disease. The anticonvulsant drugs currently used for seizure control are associated with adverse reactions, making it important to search for more effective drugs with fewer adverse reactions. There is increasing evidence that endocannabinoids can pharmacologically modulate action against seizure and antiepileptic disorders. Therefore, the objective of this study is to investigate the anticonvulsant effects of fatty acid amides (FAAs) in a pentylenetetrazole (PTZ)-induced seizure model in mice. FAAs (FAA1 and FAA2) are obtained from Carapa guianensis oil by biocatalysis and are characterized by Fourier Transform Infrared Analysis (FT-IR) and Gas Chromatography-Mass Spectrometry (GC-MS). Only FAA1 is effective in controlling the increased latency time of the first myoclonic jerk and in significantly decreasing the total duration of tonic-clonic seizures relative to the pentylenetetrazol model. Also, electrocortical alterations produced by pentylenetetrazol are reduced when treated by FAA1 that subsequently decreased wave amplitude and energy in Beta rhythm. The anticonvulsant effects of FAA1 are reversed by flumazenil, a benzodiazepine antagonist on Gamma-Aminobutyric Acid-A (GABA-A) receptors, indicating a mode of action via the benzodiazepine site of these receptors. To conclude, the FAA obtained from C. guianensis oil is promising against PTZ-induced seizures.
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Affiliation(s)
- Fábio Rodrigues de Oliveira
- Programa de Pós graduação em Neurociências e Biologia Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil; (F.R.d.O.)
- Laboratório de Neuroquímica Molecular e Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
- Laboratório de Controle de Qualidade e Bromatologia, Curso de Farmácia, Departamento de Ciências Biológicas e da Saúde, Universidade Federal do Amapá, Macapá 68902-280, Brazil
| | - Keuri Eleuterio Rodrigues
- Programa de Pós graduação em Neurociências e Biologia Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil; (F.R.d.O.)
- Laboratório de Neuroquímica Molecular e Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
| | - Moisés Hamoy
- Laboratório de Farmacologia e Toxicologia de Produtos Naturais, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
| | - Ícaro Rodrigues Sarquis
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas e Tecnológicas, Universidade Federal do Amapá, Macapá 68902-280, Brazil
- Programa de Pós graduação em Ciências Farmacêuticas, Departamento de Ciências Biológicas e da saúde, Universidade Federal do Amapá, Macapá 68902-280, Brazil
| | - Akira Otake Hamoy
- Laboratório de Farmacologia e Toxicologia de Produtos Naturais, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
| | - Maria Elena Crespo Lopez
- Programa de Pós graduação em Neurociências e Biologia Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil; (F.R.d.O.)
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
| | - Irlon Maciel Ferreira
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas e Tecnológicas, Universidade Federal do Amapá, Macapá 68902-280, Brazil
- Programa de Pós graduação em Ciências Farmacêuticas, Departamento de Ciências Biológicas e da saúde, Universidade Federal do Amapá, Macapá 68902-280, Brazil
| | - Barbarella de Matos Macchi
- Laboratório de Neuroquímica Molecular e Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
| | - José Luiz Martins do Nascimento
- Programa de Pós graduação em Neurociências e Biologia Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil; (F.R.d.O.)
- Laboratório de Neuroquímica Molecular e Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil
- Programa de Pós graduação em Ciências Farmacêuticas, Departamento de Ciências Biológicas e da saúde, Universidade Federal do Amapá, Macapá 68902-280, Brazil
- Instituto Nacional de Ciência e Tecnologia em Neuroimunomodulação (INCT-NIM), Rio de Janeiro, RJ 21040-900, Brazil
- Correspondence: or
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Pinky PD, Bloemer J, Smith WD, Moore T, Hong H, Suppiramaniam V, Reed MN. Prenatal cannabinoid exposure and altered neurotransmission. Neuropharmacology 2019; 149:181-194. [PMID: 30771373 DOI: 10.1016/j.neuropharm.2019.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/18/2019] [Accepted: 02/12/2019] [Indexed: 11/26/2022]
Abstract
Marijuana is one of the most commonly used illicit drugs worldwide. In addition, use of synthetic cannabinoids is increasing, especially among adolescents and young adults. Although human studies have shown that the use of marijuana during pregnancy leads to adverse behavioral effects, such as deficiencies in attention and executive function in affected offspring, the rate of marijuana use among pregnant women is steadily increasing. Various aspects of human behavior including emotion, learning, and memory are dependent on complex interactions between multiple neurotransmitter systems that are especially vulnerable to alterations during the developmental period. Thus, exploration of neurotransmitter changes in response to prenatal cannabinoid exposure is crucial to develop an understanding of how homeostatic imbalance and various long-term neurobehavioral deficits manifest following the abuse of marijuana or other synthetic cannabinoids during pregnancy. Current literature confirms that vast alterations to neurotransmitter systems are present following prenatal cannabinoid exposure, and many of these alterations within the brain are region specific, time-dependent, and sexually dimorphic. In this review, we aim to provide a summary of observed changes to various neurotransmitter systems following cannabinoid exposure during pregnancy and to draw possible correlations to reported behavioral alterations in affected offspring.
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Affiliation(s)
- Priyanka D Pinky
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA
| | - Jenna Bloemer
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA
| | - Warren D Smith
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA
| | - Timothy Moore
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA; Center for Neuroscience Initiative, Auburn University, Auburn, AL, USA
| | - Hao Hong
- Department of Pharmacology, China Pharmaceutical University, Nanjing, China
| | - Vishnu Suppiramaniam
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA; Center for Neuroscience Initiative, Auburn University, Auburn, AL, USA.
| | - Miranda N Reed
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA; Center for Neuroscience Initiative, Auburn University, Auburn, AL, USA.
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8
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Kodirov SA. Addictive neurons. THERAPEUTIC TARGETS FOR NEUROLOGICAL DISEASES 2017; 4:e1498. [PMID: 28649663 PMCID: PMC5479441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Since the reward center is considered to be the area tegmentalis ventralis of the hypothalamus, logically its neurons could mainly be responsible for addiction. However, the literature asserts that almost any neurons of CNS can respond to one or another addictive compound. Obviously not only addictive nicotine, but also alcohol, amphetamine, cannabis, cocaine, heroin and morphine may influence dopaminergic cells alone in VTA. Moreover, paradoxically some of these drugs ameliorate symptoms, counterbalance syndromes, cure diseases and improve health, not only those related to the CNS and in adults, but also almost all other organs and in children, e.g. epilepsy.
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Affiliation(s)
- Sodikdjon A. Kodirov
- I. P. Pavlov Department of Physiology, State Research Institute of Experimental Medicine, Russian Academy of Medical Sciences, Saint Petersburg 197376, Russia
- University of Texas at Brownsville, Department of Biological Sciences, Texas 78520, USA
- Johannes Gutenberg University, 55099 Mainz, Germany
- Almazov Federal Heart, Blood and Endocrinology Centre, Saint Petersburg 197341, Russia
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
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Nazari M, Komaki A, Karamian R, Shahidi S, Sarihi A, Asadbegi M. The interactive role of CB1 and GABAB receptors in hippocampal synaptic plasticity in rats. Brain Res Bull 2016; 120:123-30. [DOI: 10.1016/j.brainresbull.2015.11.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 01/25/2023]
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Effects of co-administration of 2-arachidonylglycerol (2-AG) and a selective µ-opioid receptor agonist into the nucleus accumbens on high-fat feeding behaviors in the rat. Brain Res 2015; 1618:309-15. [PMID: 26100333 DOI: 10.1016/j.brainres.2015.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 05/26/2015] [Accepted: 06/12/2015] [Indexed: 12/14/2022]
Abstract
Previous research has demonstrated that the nucleus accumbens is a site where opioids and cannabinoids interact to alter feeding behavior. However, the influence of the endocannabinoid 2-arachidonylglycerol (2-AG) on the well-characterized model of intra-accumbens opioid driven high-fat feeding behavior has not been explored. The present experiments examined high-fat feeding associated behaviors produced by the interaction of 2-AG and the μ-opioid receptor agonist DAla(2),N,Me-Phe(4),Gly-ol(5)-enkaphalin (DAMGO) administered into the nucleus accumbens. Sprague-Dawley rats were implanted with bilateral cannulae aimed at the nucleus accumbens and were co-administered both a sub-threshold dose of 2-AG (0 or 0.25 μg/0.5 μl/side) and DAMGO (0, 0.025 μg or 0.25 μg/0.5 μl/side) in all dose combinations, and in a counterbalanced order. Animals were then immediately allowed a 2h-unrestricted access period to a palatable high-fat diet. Consumption, number and duration of food hopper entries, and locomotor activity were all monitored. DAMGO treatment led to an increase in multiple behaviors, including consumption, duration of food hopper entry, and locomotor activity. However, combined intra-accumbens administration of DAMGO and a subthreshold dose of 2-AG led to a significant increase in number of food hopper entries and locomotor activity, compared to DAMGO by itself. The results confirm that intra-accumbens administration of subthreshold dose of the endogenous cannabinoid 2-AG increases the DAMGO-induced approach and locomotor behaviors associated with high-fat feeding.
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Saffarzadeh F, Eslamizade MJ, Ghadiri T, Modarres Mousavi SM, Hadjighassem M, Gorji A. Effects of TRPV1 on the hippocampal synaptic plasticity in the epileptic rat brain. Synapse 2015; 69:375-83. [PMID: 25967571 DOI: 10.1002/syn.21825] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/04/2015] [Accepted: 04/20/2015] [Indexed: 12/27/2022]
Abstract
Temporal lobe epilepsy is often presented by medically intractable recurrent seizures due to dysfunction of temporal lobe structures, mostly the temporomesial structures. The role of transient receptor potential vaniloid 1 (TRPV1) activity on synaptic plasticity of the epileptic brain tissues was investigated. We studied hippocampal TRPV1 protein content and distribution in the hippocampus of epileptic rats. Furthermore, the effects of pharmacologic modulation of TRPV1 receptors on field excitatory postsynaptic potentials have been analyzed after induction of long term potentiation (LTP) in the hippocampal CA1 and CA3 areas after 1 day (acute phase) and 3 months (chronic phase) of pilocarpine-induced status epilepticus (SE). A higher expression of TRPV1 protein in the hippocampus as well as a higher distribution of this channel in CA1 and CA3 areas in both acute and chronic phases of pilocarpine-induced SE was observed. Activation of TRPV1 using capsaicin (1 µM) enhanced LTP induction in CA1 region in non-epileptic rats. Inhibition of TRPV1 by capsazepine (10 µM) did not affect LTP induction in non-epileptic rats. In acute phase of SE, activation of TRPV1 enhanced LTP in both CA1 and CA3 areas but TRPV1 inhibition did not affect LTP. In chronic phase of SE, application of TRPV1 antagonist enhanced LTP induction in CA1 and CA3 regions but TRPV1 activation had no effect on LTP. These findings indicate that a higher expression of TRPV1 in epileptic conditions is accompanied by a functional impact on the synaptic plasticity in the hippocampus. This suggests TRPV1 as a potential target in treatment of seizure attacks.
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Affiliation(s)
- Fatemeh Saffarzadeh
- Department of Neuroscience, School of Medical Advanced Studies, Iran University of Medical Sciences, Tehran, Iran.,Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran
| | - Mohammad J Eslamizade
- Department of Neuroscience, School of Medical Advanced Studies, Iran University of Medical Sciences, Tehran, Iran.,Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.,Department of Physiology and Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tahereh Ghadiri
- Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran
| | | | - Mahmoudreza Hadjighassem
- Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Gorji
- Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.,Klinik Und Poliklinik Für Neurochirurgie, Department of Neurology, Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany
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Attenuation of kainic acid-induced status epilepticus by inhibition of endocannabinoid transport and degradation in guinea pigs. Epilepsy Res 2015; 111:33-44. [PMID: 25769371 DOI: 10.1016/j.eplepsyres.2015.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 11/26/2014] [Accepted: 01/14/2015] [Indexed: 02/08/2023]
Abstract
Status epilepticus (SE) is a medical emergency associated with a high rate of mortality if not treated promptly. Exogenous and endogenous cannabinoids have been shown to possess anticonvulsant properties both in vivo and in vitro. Here we study the influence of endocannabinoid metabolism on the development of kainic acid-induced SE in guinea pigs. For this purpose, the inhibitors of endocannabinoid transport, AM404, and enzymatic (fatty acid amide hydrolase) degradation, URB597, were applied. Cannabinoid CB1 receptor antagonist, AM251, was also tested. Animal behavior as well as local electric field potentials in four structures: medial septum, hippocampus, entorhinal cortex and amygdala were analyzed when AM404 (120nmol), URB597 (4.8nmol) or AM251 (20nmol) were administrated alone or together with 0.4μg of kainic acid. All substances were injected i.c.v. AM404, URB597 or AM251 administered alone did not alter markedly local field potentials of all four studied structures in the long-term compared with their basal activity. AM404 and URB597 significantly alleviated kainic acid-induced SE, decreasing behavioral manifestations, duration of seizure events and SE in general without changing the amplitude of local field potentials. AM251 did not produce distinct effects on SE in terms of our experimental paradigm. There was no apparent change of the seizure initiation pattern when kainic acid was coadministrated with AM404, URB597 or AM251. The present study provides electrophysiologic and behavioral evidences that inhibition of endocannabinoid metabolism plays a protective role against kainic acid-induced SE and may be employed for therapeutic purposes. Further investigations of the influences of cannabinoid-related compounds on SE genesis and especially epileptogenesis are required.
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Sheinin A, Lavi A, Michaelevski I. StimDuino: an Arduino-based electrophysiological stimulus isolator. J Neurosci Methods 2015; 243:8-17. [PMID: 25619449 DOI: 10.1016/j.jneumeth.2015.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/08/2015] [Accepted: 01/11/2015] [Indexed: 11/15/2022]
Abstract
BACKGROUND Electrical stimulus isolator is a widely used device in electrophysiology. The timing of the stimulus application is usually automated and controlled by the external device or acquisition software; however, the intensity of the stimulus is adjusted manually. Inaccuracy, lack of reproducibility and no automation of the experimental protocol are disadvantages of the manual adjustment. To overcome these shortcomings, we developed StimDuino, an inexpensive Arduino-controlled stimulus isolator allowing highly accurate, reproducible automated setting of the stimulation current. NEW METHOD The intensity of the stimulation current delivered by StimDuino is controlled by Arduino, an open-source microcontroller development platform. The automatic stimulation patterns are software-controlled and the parameters are set from Matlab-coded simple, intuitive and user-friendly graphical user interface. The software also allows remote control of the device over the network. RESULTS Electrical current measurements showed that StimDuino produces the requested current output with high accuracy. In both hippocampal slice and in vivo recordings, the fEPSP measurements obtained with StimDuino and the commercial stimulus isolators showed high correlation. COMPARISON WITH EXISTING METHODS Commercial stimulus isolators are manually managed, while StimDuino generates automatic stimulation patterns with increasing current intensity. The pattern is utilized for the input-output relationship analysis, necessary for assessment of excitability. In contrast to StimuDuino, not all commercial devices are capable for remote control of the parameters and stimulation process. CONCLUSIONS StimDuino-generated automation of the input-output relationship assessment eliminates need for the current intensity manually adjusting, improves stimulation reproducibility, accuracy and allows on-site and remote control of the stimulation parameters.
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Affiliation(s)
- Anton Sheinin
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel; Sagol School of Neuroscience, Tel-Aviv University, Ramat Aviv 69978, Israel
| | - Ayal Lavi
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel; Sagol School of Neuroscience, Tel-Aviv University, Ramat Aviv 69978, Israel
| | - Izhak Michaelevski
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel; Sagol School of Neuroscience, Tel-Aviv University, Ramat Aviv 69978, Israel.
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Johnson BN, Palmer CP, Bourgeois EB, Elkind JA, Putnam BJ, Cohen AS. Augmented Inhibition from Cannabinoid-Sensitive Interneurons Diminishes CA1 Output after Traumatic Brain Injury. Front Cell Neurosci 2014; 8:435. [PMID: 25565968 PMCID: PMC4271495 DOI: 10.3389/fncel.2014.00435] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/02/2014] [Indexed: 11/15/2022] Open
Abstract
The neurological impairments associated with traumatic brain injury include learning and memory deficits and increased risk of seizures. The hippocampus is critically involved in both of these phenomena and highly susceptible to damage by traumatic brain injury. To examine network activity in the hippocampal CA1 region after lateral fluid percussion injury, we used a combination of voltage-sensitive dye, field potential, and patch clamp recording in mouse hippocampal brain slices. When the stratum radiatum (SR) was stimulated in slices from injured mice, we found decreased depolarization in SR and increased hyperpolarization in stratum oriens (SO), together with a decrease in the percentage of pyramidal neurons firing stimulus-evoked action potentials. Increased hyperpolarization in SO persisted when glutamatergic transmission was blocked. However, we found no changes in SO responses when the alveus was stimulated to directly activate SO. These results suggest that the increased SO hyperpolarization evoked by SR stimulation was mediated by interneurons that have cell bodies and/or axons in SR, and form synapses in stratum pyramidale and SO. A low concentration (100 nM) of the synthetic cannabinoid WIN55,212-2, restored CA1 output in slices from injured animals. These findings support the hypothesis that increased GABAergic signaling by cannabinoid-sensitive interneurons contributes to the reduced CA1 output following traumatic brain injury.
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Affiliation(s)
- Brian N Johnson
- Children's Hospital of Philadelphia Research Institute, Children's Hospital of Philadelphia , Philadelphia, PA , USA
| | - Chris P Palmer
- Department of Neuroscience, University of Pennsylvania School of Medicine , Philadelphia, PA , USA
| | - Elliot B Bourgeois
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA
| | - Jaclynn A Elkind
- Children's Hospital of Philadelphia Research Institute, Children's Hospital of Philadelphia , Philadelphia, PA , USA
| | - Brendan J Putnam
- Children's Hospital of Philadelphia Research Institute, Children's Hospital of Philadelphia , Philadelphia, PA , USA
| | - Akiva S Cohen
- Children's Hospital of Philadelphia Research Institute, Children's Hospital of Philadelphia , Philadelphia, PA , USA ; Department of Pediatrics, University of Pennsylvania School of Medicine , Philadelphia, PA , USA
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15
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D’Addario C, Micioni Di Bonaventura M, Pucci M, Romano A, Gaetani S, Ciccocioppo R, Cifani C, Maccarrone M. Endocannabinoid signaling and food addiction. Neurosci Biobehav Rev 2014; 47:203-24. [DOI: 10.1016/j.neubiorev.2014.08.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 07/28/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
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16
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Distinct modulation of the endocannabinoid system upon kainic acid-induced in vivo seizures and in vitro epileptiform bursting. Mol Cell Neurosci 2014; 62:1-9. [PMID: 25064144 DOI: 10.1016/j.mcn.2014.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/06/2014] [Accepted: 07/23/2014] [Indexed: 12/11/2022] Open
Abstract
There is clear evidence on the neuroprotective role of the endocannabinoid (eCB) signaling cascade in various models of epilepsy. In particular, increased levels of eCBs protect against kainic acid (KA)-induced seizures. However, the molecular mechanisms underlying this effect and its age-dependence are still unknown. To clarify this issue, we investigated which step of the biosynthetic and catabolic pathways of the eCBs may be responsible for the eCB-mediated neuroprotection in the hippocampus of P14 and P56-70 KA-treated rats. We found that both anandamide and N-palmitoylethanolamine, together with their biosynthetic enzyme significantly increased in the hippocampus of younger KA-treated rats, while decreasing in adults. In contrast, the levels of the other major eCB, 2-arachidonoylglycerol, similar to its biosynthetic enzyme, were higher in the hippocampus of P56-70 compared to P14 rats. In line with these data, extracellular field recordings in CA1 hippocampus showed that enhancement of endogenous AEA and 2-AG significantly counteracted KA-induced epileptiform bursting in P56-70 and P14 rats, respectively. On the contrary, while the CB1R antagonist SR141716 per se did not affect the population spike, it did worsen KA-induced bursts, confirming increased eCB tone upon KA treatment. Altogether these data indicate an age-specific alteration of the eCB system caused by KA and provide insights for the protective mechanism of the cannabinoid system against epileptiform discharges.
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17
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Wang Y, Cui H, Wang W, Zhao B, Lai J. The region-specific activation of Ca2+/calmodulin dependent protein kinase II and extracellular signal-regulated kinases in hippocampus following chronic alcohol exposure. Brain Res Bull 2012; 89:191-6. [PMID: 22960015 DOI: 10.1016/j.brainresbull.2012.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 08/22/2012] [Indexed: 02/02/2023]
Abstract
Previous studies suggest that hippocampal CA1, CA3, and DG regions may have distinct roles in alcohol dependence. Extracellular signal-regulated kinases (ERKs) and Ca(2+)/calmodulin dependent protein kinase II (CaMKII) have been shown to contribute to the molecular mechanism underlying drug dependence and relapse, and there may be an interaction between the activation of ERKs and CaMKII. However, little is known regarding the mechanisms underlying the effects of alcohol exposure, withdrawal, and relapse, particularly with regard to the interaction between CaMKII and ERK1/2 signaling in hippocampal subregions. In the present study, rats were provided water containing 6% alcohol as their only drinking source. We found that alcohol exerted locomotor stimulant and anxiolytic effects on rats in open field behaviors. Following chronic alcohol exposure, phospho-ERK1/2 was significantly decreased in the DG. Alcohol withdrawal was associated with an increase of phospho-ERK1/2 in the CA1 and DG, while alcohol re-exposure induced a decrease of phospho-ERK1/2 in the CA1, CA3, and DG. The activation of CaMKII (Thr286) correlated with the effects of alcohol on phospho-ERK1/2. Our results indicate that region-specific activation CaMKII-ERK1/2 signaling in the hippocampal CA1 and DG may play an important role in alcohol dependence.
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Affiliation(s)
- YunPeng Wang
- Department of Forensic Science, School of Medicine, Xi'an Jiaotong University, Xi'an, PR China
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18
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Rosenbaum CD, Carreiro SP, Babu KM. Here today, gone tomorrow…and back again? A review of herbal marijuana alternatives (K2, Spice), synthetic cathinones (bath salts), kratom, Salvia divinorum, methoxetamine, and piperazines. J Med Toxicol 2012; 8:15-32. [PMID: 22271566 DOI: 10.1007/s13181-011-0202-2] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Despite their widespread Internet availability and use, many of the new drugs of abuse remain unfamiliar to health care providers. The herbal marijuana alternatives, like K2 or Spice, are a group of herbal blends that contain a mixture of plant matter in addition to chemical grade synthetic cannabinoids. The synthetic cathinones, commonly called "bath salts," have resulted in nationwide emergency department visits for severe agitation, sympathomimetic toxicity, and death. Kratom, a plant product derived from Mitragyna speciosa Korth, has opioid-like effects, and has been used for the treatment of chronic pain and amelioration of opioid-withdrawal symptoms. Salvia divinorum is a hallucinogen with unique pharmacology that has therapeutic potential but has been banned in many states due to concerns regarding its psychiatric effects. Methoxetamine has recently become available via the Internet and is marked as "legal ketamine." Moreover, the piperazine derivatives, a class of amphetamine-like compounds that includes BZP and TMFPP, are making a resurgence as "legal Ecstasy." These psychoactives are available via the Internet, frequently legal, and often perceived as safe by the public. Unfortunately, these drugs often have adverse effects, which range from minimal to life-threatening. Health care providers must be familiar with these important new classes of drugs. This paper discusses the background, pharmacology, clinical effects, detection, and management of synthetic cannabinoid, synthetic cathinone, methoxetamine, and piperazine exposures.
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Affiliation(s)
- Christopher D Rosenbaum
- Division of Medical Toxicology, Department of Emergency Medicine, University of Massachusetts, Worcester, MA, USA
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19
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Messer RD, Levine ES. Epileptiform activity in the CA1 region of the hippocampus becomes refractory to attenuation by cannabinoids in part because of endogenous γ-aminobutyric acid type B receptor activity. J Neurosci Res 2012; 90:1454-63. [PMID: 22388975 DOI: 10.1002/jnr.23027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 11/30/2011] [Accepted: 12/12/2011] [Indexed: 12/18/2022]
Abstract
The anticonvulsant properties of marijuana have been known for centuries. The recently characterized endogenous cannabinoid system thus represents a promising target for novel anticonvulsant agents; however, administration of exogenous cannabinoids has shown mixed results in both human epilepsy and animal models. The ability of cannabinoids to attenuate release of both excitatory and inhibitory neurotransmitters may explain the variable effects of cannabinoids in different models of epilepsy, but this has not been well explored. Using acute mouse brain slices, we monitored field potentials in the CA1 region of the hippocampus to characterize systematically the effects of the cannabinoid agonist WIN55212-2 (WIN) on evoked basal and epileptiform activity. WIN, acting presynaptically, significantly reduced the amplitude and slope of basal field excitatory postsynaptic potentials as well as stimulus-evoked epileptiform responses induced by omission of magnesium from the extracellular solution. In contrast, the combination of omission of magnesium plus elevation of potassium induced an epileptiform response that was refractory to attenuation by WIN. The effect of WIN in this model was partially restored by blocking γ-aminobutyric acid type B (GABA(B) ), but not GABA(A) , receptors. Subtle differences in models of epileptiform activity can profoundly alter the efficacy of cannabinoids. Endogenous GABA(B) receptor activation played a role in the decreased cannabinoid sensitivity observed for epileptiform activity induced by omission of magnesium plus elevation of potassium. These results suggest that interplay between presynaptic G protein-coupled receptors with overlapping downstream targets may underlie the variable efficacy of cannabinoids in different models of epilepsy.
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Affiliation(s)
- Ricka D Messer
- Department of Neuroscience, University of Connecticut Health Center, Farmington,CT 06030, USA
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20
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Roerig JL, Steffen KJ, Mitchell JE. Atypical antipsychotic-induced weight gain: insights into mechanisms of action. CNS Drugs 2011; 25:1035-59. [PMID: 22133326 DOI: 10.2165/11596300-000000000-00000] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prescriptions for second-generation antipsychotics (SGAs) have surpassed those for first-generation agents in the treatment of schizophrenia and bipolar disorder. While SGAs have the benefit of a much reduced risk of causing movement disorders, they have been associated with weight gain and metabolic effects. These adverse reactions are not uncommon, and threaten to have a significant impact on the patient's health over the long-term treatment that the patient requires. Currently, the aetiology of these effects is not known. This article reviews the data exploring the weight gain phenomenon. The literature was reviewed from searches of PubMed and the references of major articles in the field. The SGAs present a heterogeneous risk for weight gain. In addition, different individuals receiving the same drug can exhibit substantially different weight changes. This pattern suggests that a group of factors are associated with the weight gain phenomenon rather than a single mechanism. Coupled with the genetic profile that the patient brings to the treatment, the risk for SGA-induced weight gain will be different for different drugs and different individuals. Targets for exploration of the weight gain phenomenon include receptor interactions involving serotonin, histamine, dopamine, adrenergic, cannabinoid and muscarinic receptors. The association of SGA-induced weight gain and the role of orexigenic and anorexigenic peptides are reviewed. Also, a brief discussion of genetic factors associated with SGA-induced weight gain is presented, including that of the serotonin 5-HT(2C) receptor gene (HTR2C) and the cannabinoid 1 receptor gene (CNR1). The most promising data associated with SGA-induced weight gain include investigations of the histamine H(1), 5-HT(2A), 5-HT(2C), muscarinic M(3) and adrenergic receptors. In addition, work in the genetic area promises to result in a better understanding of the variation in risk associated with different individuals.
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Affiliation(s)
- James L Roerig
- Department of Clinical Neuroscience, University of North Dakota School of Medicine and Health Sciences, Fargo, ND, USA
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21
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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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22
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Kufahl PR, Olive MF. Investigating Methamphetamine Craving Using the Extinction-Reinstatement Model in the Rat. JOURNAL OF ADDICTION RESEARCH & THERAPY 2011; S1:003. [PMID: 22428089 PMCID: PMC3305273 DOI: 10.4172/2155-6105.s1-003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Like all other drugs of abuse, the primary therapeutic objective for treating methamphetamine addiction research is the maintenance of abstinence and prevention of relapse to habitual drug-taking. Compounds with the potential to prevent relapse are often investigated in rats that are trained to self-administer intravenous methamphetamine, subjected to extinction training where responding is no longer reinforced, and then given tests for reinstatement of drug-seeking behavior triggered by methamphetamine injections or re-exposure to drug-paired cues. Experimental compounds are administered to the animals prior to the reinstatement tests to evaluate their potential for attenuating or preventing drug-seeking behavior. This article describes the common procedures of the extinction-reinstatement model in studies of this type, and identifies areas of discrepancy. This is followed by a comprehensive overview of the currently published anti-reinstatement effects of pharmacological compounds, classified by the most relevant neurological systems associated with these compounds. The article concludes with a brief discussion of how the study of anti-reinstatement effects can be expanded to further verify existing positive results or to find novel neurobiological targets.
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Affiliation(s)
- Peter R. Kufahl
- Department of Psychology, Arizona State University, Tempe, AZ85287, USA
| | - M. Foster Olive
- Department of Psychology, Arizona State University, Tempe, AZ85287, USA
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23
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Bailey CR, Neumeister A. Cb1 receptor-mediated signaling emerges as a novel lead to evidence-based treatment development for stress-related psychopathology. Neurosci Lett 2011; 502:1-4. [DOI: 10.1016/j.neulet.2011.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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24
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Abstract
The endocannabinoid (ECB) system has been found throughout the central nervous system and modulates cell excitability in various forms of short-term plasticity. ECBs and their receptors have also been localized to all retinal cells, and cannabinoid receptor activation has been shown to alter voltage-dependent conductances in several different retinal cell types, suggesting a possible role for cannabinoids in retinal processing. Their effects on synaptic transmission in the mammalian retina, however, have not been previously investigated. Here, we show that exogenous cannabinoids alter spontaneous synaptic transmission onto retinal ganglion cells (RGCs). Using whole-cell voltage-clamp recordings in whole-mount retinas, we measured spontaneous postsynaptic currents (SPSCs) in RGCs in adult and young (P14-P21) mice. We found that the addition of an exogenous cannabinoid agonist, WIN55212-2 (5 μM), caused a significant reversible reduction in the frequency of SPSCs. This change, however, did not alter the kinetics of the SPSCs, indicating a presynaptic locus of action. Using blockers to isolate inhibitory or excitatory currents, we found that cannabinoids significantly reduced the release probability of both GABA and glutamate, respectively. While the addition of cannabinoids reduced the frequency of both GABAergic and glutamatergic SPSCs in both young and adult mice, we found that the largest effect was on GABA-mediated currents in young mice. These results suggest that the ECB system may potentially be involved in the modulation of signal transmission in the retina. Furthermore, they suggest that it might play a role in the developmental maturation of synaptic circuits, and that exogenous cannabinoids are likely able to disrupt retinal processing and consequently alter vision.
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Naderi N, Ahmad-Molaei L, Aziz Ahari F, Motamedi F. Modulation of anticonvulsant effects of cannabinoid compounds by GABA-A receptor agonist in acute pentylenetetrazole model of seizure in rat. Neurochem Res 2011; 36:1520-5. [PMID: 21516342 DOI: 10.1007/s11064-011-0479-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2011] [Indexed: 11/26/2022]
Abstract
Cannabinoid system plays an important role in controlling neuronal excitability and brain function. On the other hand, modulation of gamma-aminobutyric acid (GABA) transmission is one of the initial strategies for the treatment of seizure. The aim of the present study was to evaluate possible interaction between cannabinoidergic and GABAergic systems in pentylenetetrazole (PTZ)-induced acute seizure in rat. Drugs were administered by intracerebroventricular (i.c.v.) administration 20 min before a single intraperitoneal (i.p.) injection of PTZ and the latency to the first generalized tonic-clonic seizure was measured. Both the cannabinoid receptor agonist WIN55212-2 (10, 30, 50 and 100 μg/rat) and the GABA-A receptor agonist isoguvacine (IGN; 10, 30 and 50 μg/rat) significantly increased the latency of seizure occurrence. Moreover, the fatty acid amide hydrolase inhibitor URB597 showed no anticonvulsive effect while the monoacyl glycerol lipase (MAGL) inhibitor URB602 (10, 50 and 100 μg/rat) protected rats against PTZ-induced seizure. Moreover, co-administration of IGN and cannabinoid compounds attenuated the anticonvulsant action of both WIN55212-2 and IGN in this model of seizure. Our data suggests that exogenous cannabinoid WIN55212-2 and MAGL inhibitor URB602 imply their antiseizure action in part through common brain receptorial system. Moreover, the antagonistic interaction of cannabinoids and IGN in protection against PTZ-induced seizure could suggest the involvement of GABAergic system in their anticonvulsant action.
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Affiliation(s)
- Nima Naderi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.
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26
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Atwood BK, Lee D, Straiker A, Widlanski TS, Mackie K. CP47,497-C8 and JWH073, commonly found in 'Spice' herbal blends, are potent and efficacious CB(1) cannabinoid receptor agonists. Eur J Pharmacol 2011; 659:139-45. [PMID: 21333643 DOI: 10.1016/j.ejphar.2011.01.066] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 01/04/2011] [Accepted: 01/25/2011] [Indexed: 12/23/2022]
Abstract
'Spice' is an herbal blend that has been reported to produce cannabis-like effects when smoked and is marketed as an alternative to marijuana. Synthetic additives have been identified in numerous 'Spice' preparations from different sources. Common among many of the preparations were the compounds JWH018 and a dimethyloctyl variant of CP47,497 (CP47,497-C8) and, more recently JWH073. The synaptic effects of each of these compounds were uncharacterized. We previously reported that JWH018 is a potent and efficacious CB(1) cannabinoid receptor agonist. In this study we have examined the abilities of CP47,497-C8 and JWH073 to inhibit neurotransmission in cultured autaptic hippocampal neurons. Each inhibited EPSCs with an efficacy and potency similar to JWH018. We also analyzed these compounds' effects on promoting internalization of CB(1) receptors in HEK293 cells stably expressing CB(1) receptors. Similar to our neurotransmission data, CP47,497-C8 internalized CB(1) in a fashion indistinguishable from JWH018. However, JWH073 was less potent and produced slower internalization than JWH018 and CP47,497-C8. It appears that 'Spice' contains a number of cannabinoid receptor agonists that activate CB(1) receptors to inhibit synaptic transmission with similar potencies and efficacies. It is highly probable that the cannabis-like effects of 'Spice' are due to the presence of these and analogous synthetic additives acting on CB(1) receptors.
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Affiliation(s)
- Brady K Atwood
- The Gill Center and Department of Psychological & Brain Sciences, Indiana University, 1101 E. 10th St, Bloomington, IN 47405, USA
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27
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Edwards JG, Gibson HE, Jensen T, Nugent F, Walther C, Blickenstaff J, Kauer JA. A novel non-CB1/TRPV1 endocannabinoid-mediated mechanism depresses excitatory synapses on hippocampal CA1 interneurons. Hippocampus 2010; 22:209-21. [PMID: 21069781 DOI: 10.1002/hipo.20884] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2010] [Indexed: 11/06/2022]
Abstract
Endocannabinoids (eCBs) mediate various forms of synaptic plasticity at excitatory and inhibitory synapses in the brain. The eCB anandamide binds to several receptors including the transient receptor potential vanilloid 1 (TRPV1) and cannabinoid receptor 1 (CB1). We recently identified that TRPV1 is required for long-term depression at excitatory synapses on CA1 hippocampal stratum radiatum interneurons. Here we performed whole-cell patch clamp recordings from CA1 stratum radiatum interneurons in rat brain slices to investigate the effect of the eCB anandamide on excitatory synapses as well as the involvement of Group I metabotropic glutamate receptors (mGluRs), which have been reported to produce eCBs endogenously. Application of the nonhydrolysable anandamide analog R-methanandamide depressed excitatory transmission to CA1 stratum radiatum interneurons by ∼50%. The Group I mGluR agonist DHPG also depressed excitatory glutamatergic transmission onto interneurons to a similar degree, and this depression was blocked by the mGluR5 antagonist MPEP (10 μM) but not by the mGluR1 antagonist CPCCOEt (50 μM). Interestingly, however, neither DHPG-mediated nor R-methanandamide-mediated depression was blocked by the TRPV1 antagonist capsazepine (10 μM), the CB1 antagonist AM-251 (2 μM) or a combination of both, suggesting the presence of a novel eCB receptor or anandamide target at excitatory hippocampal synapses. DHPG also occluded R-methanandamide depression, suggesting the possibility that the two drugs elicit synaptic depression via a shared signaling mechanism. Collectively, this study illustrates a novel CB1/TRPV1-independent eCB pathway present in the hippocampus that mediates depression at excitatory synapses on CA1 stratum radiatum interneurons.
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Affiliation(s)
- Jeffrey G Edwards
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, Rhode Island, USA.
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A common polymorphism in the cannabinoid receptor 1 (CNR1) gene is associated with antipsychotic-induced weight gain in Schizophrenia. Neuropsychopharmacology 2010; 35:1315-24. [PMID: 20107430 PMCID: PMC3055343 DOI: 10.1038/npp.2009.235] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antipsychotic-induced weight gain has emerged as a serious complication in the treatment of patients with atypical antipsychotic drugs. The cannabinoid receptor 1 (CNR1) is expressed centrally in the hypothalamic region and associated with appetite and satiety, as well as peripherally. An antagonist of CNR1 (rimonabant) has been effective in causing weight loss in obese patients indicating that CNR1 might be important in antipsychotic-induced weight gain. Twenty tag SNPs were analyzed in 183 patients who underwent treatment (with either clozapine, olanzapine, haloperidol, or risperidone) for chronic schizophrenia were evaluated for antipsychotic-induced weight gain for up to 14 weeks. The polymorphism rs806378 was nominally associated with weight gain in patients of European ancestry treated with clozapine or olanzapine. 'T' allele carriers (CT+TT) gained more weight (5.96%), than the CC carriers (2.76%, p=0.008, FDR q-value=0.12). This translated into approximately 2.2 kg more weight gain in patients carrying the T allele than the patients homozygous for the CC genotype (CC vs CT+TT, 2.21+/-4.51 vs 4.33+/-3.89 kg; p=0.022). This was reflected in the allelic analysis (C vs T allele, 3.84 vs 5.83%, p=0.035). We conducted electrophoretic mobility shift assays which showed that the presence of the T allele created a binding site for arylhydrocarbon receptor translocator (ARNT), a member of the basic helix-loop-helix/Per-Arnt-Sim protein family. In this study, we provide evidence that the CNR1 gene may be associated with antipsychotic-induced weight gain in chronic schizophrenia patients. However, these observations were made in a relatively small patient population; therefore these results need to be replicated in larger sample sets.
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Atwood BK, Huffman J, Straiker A, Mackie K. JWH018, a common constituent of 'Spice' herbal blends, is a potent and efficacious cannabinoid CB receptor agonist. Br J Pharmacol 2010; 160:585-93. [PMID: 20100276 DOI: 10.1111/j.1476-5381.2009.00582.x] [Citation(s) in RCA: 214] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND AND PURPOSE 'Spice' is an herbal blend primarily marketed in Europe as a mild hallucinogen with prominent cannabis-like effects and as a legal alternative to cannabis. However, a recent report identified a number of synthetic additives in samples of 'Spice'. One of these, the indole derivative JWH018, is a ligand for the cannabinoid receptor 1 (CB(1)) cannabinoid receptor and inhibits cAMP production in CB(1) receptor-expressing CHO cells. Other effects of JWH018 on CB(1) receptor-mediated signalling are not known, particularly in neurons. Here we have evaluated the signalling pathways activated by JWH018 at CB(1) receptors. EXPERIMENTAL APPROACH We investigated the effects of JWH018 on neurotransmission in cultured autaptic hippocampal neurons. We further analysed its activation of ERK1/2 mitogen activated protein kinase (MAPK) and internalization of CB(1) receptors in HEK293 cells stably expressing this receptor. KEY RESULTS In cultured autaptic hippocampal neurons, JWH018 potently inhibited excitatory postsynaptic currents (IC(50)= 14.9 nM) in a concentration- and CB(1) receptor-dependent manner. Furthermore, it increased ERK1/2 MAPK phosphorylation (EC(50)= 4.4 nM). We also found that JWH018 potently induced rapid and robust CB(1) receptor internalization (EC(50)= 2.8 nM; t(1/2)= 17.3 min). CONCLUSIONS AND IMPLICATIONS JWH018, a prominent component of several herbal preparations marketed for their psychoactivity, is a potent and effective CB(1) receptor agonist that activates multiple CB(1) receptor signalling pathways. Thus, it is likely that the subjective effects of 'Spice' are due to activation of cannabinoid CB(1) receptors by JWH018, added to this herbal preparation.
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Affiliation(s)
- Brady K Atwood
- The Gill Center and the Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN 47405, USA
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Romigi A, Bari M, Placidi F, Marciani MG, Malaponti M, Torelli F, Izzi F, Prosperetti C, Zannino S, Corte F, Chiaramonte C, Maccarrone M. Cerebrospinal fluid levels of the endocannabinoid anandamide are reduced in patients with untreated newly diagnosed temporal lobe epilepsy. Epilepsia 2009; 51:768-72. [PMID: 19817812 DOI: 10.1111/j.1528-1167.2009.02334.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE The endocannabinoid system is involved in excitatory/inhibitory balance mechanisms within the central nervous system (CNS). Growing evidence shows that its perturbation leads to development of epileptic seizures in experimental models, thus indicating that endocannabinoids play an intrinsic protective role in suppressing pathologic neuronal excitability. Experimental data also demonstrate that the endocannabinoid anandamide (AEA) can antagonize epileptic discharges in hippocampal tissue. The objective of our study was to measure endocannabinoids levels in the cerebrospinal fluid (CSF) of drug-naive patients affected by temporal lobe epilepsy (TLE). METHODS We measured the levels of both AEA and the other endocannabinoid, 2-arachidonoylglycerol (2-AG), in the CSF of drug-naive patients with TLE. RESULTS A significant reduction of AEA was found in the CSF of patients with compared with healthy controls (epileptic patients = 2.55 +/- 1.78 pmol/ml; healthy controls = 11.65 +/- 7.53 pmol/ml; n = 9 for both groups, p < 0.01). 2-AG levels, however, were not affected (epileptic patients = 209.5 +/- 146.56; healthy controls = 159.6 +/- 110.2) (n = 6 for both groups, p = 0.48). DISCUSSION Our findings seem to be consistent with experimental evidence demonstrating a significant prevention of epileptic seizures induced by endocannabinoids in models of epilepsy. Furthermore, they support the hypothesis that AEA may be involved in its pathogenesis, suggesting a hypothetical primary impairment of the endocannabinoid system in untreated TLE. The actual role of this in vivo dysregulation still remains unclear.
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Affiliation(s)
- Andrea Romigi
- Dipartimento di Neuroscienze, Università degli Studi di Roma Tor Vergata, Roma, Italy.
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Bajo M, Roberto M, Schweitzer P. Differential alteration of hippocampal excitatory synaptic transmission by cannabinoid ligands. J Neurosci Res 2009; 87:766-75. [PMID: 18816788 DOI: 10.1002/jnr.21889] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cannabinoid compounds affect synaptic activity and plasticity in numerous brain areas by activating CB1 receptors (CB1). In hippocampus, varying results have been obtained on the extent and site of cannabinoid actions on excitatory transmission, ranging from no effect to complete obliteration of synaptic responses. Here we used the rat hippocampal slice preparation to study and compare the effect of various synthetic and endogenous CB1 ligands on excitatory synaptic transmission. The full CB1 agonist WIN55212-2 (WIN2) greatly decreased excitatory synaptic transmission by 62%. The effect of WIN-2 was concentration dependent (EC50 of 200 nM) and completely prevented by CB1 antagonists. The nondegradable partial CB1 agonist R1-methanandamide (mAEA) decreased transmission by 25% and the endocannabinoids 2-arachidonylglycerol (2-AG) and anandamide (AEA) had no significant effect. The action of AEA was improved by inhibiting its degradation but not its transport. The effect of 2-AG was enhanced upon inhibition of COX-2 but remained unchanged with blockade of monoacylglycerol lipase (MAGL). The observed effects were prevented by CB1 antagonists regardless of the ligand used, and paired-pulse paradigms pointed to presynaptic mechanisms of cannabinoid action. Our results show that cannabinoid effects on neuronal activity differ widely according to the CB1 ligand used. We observed large differences between full (synthetic) and partial (endogenous) CB1 agonists in altering synaptic transmission, notably because of the involvement of active degradation mechanisms.
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Affiliation(s)
- Michal Bajo
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California 92037, USA
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Downregulation of the CB1 cannabinoid receptor and related molecular elements of the endocannabinoid system in epileptic human hippocampus. J Neurosci 2008; 28:2976-90. [PMID: 18354002 DOI: 10.1523/jneurosci.4465-07.2008] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Endocannabinoid signaling is a key regulator of synaptic neurotransmission throughout the brain. Compelling evidence shows that its perturbation leads to development of epileptic seizures, thus indicating that endocannabinoids play an intrinsic protective role in suppressing pathologic neuronal excitability. To elucidate whether long-term reorganization of endocannabinoid signaling occurs in epileptic patients, we performed comparative expression profiling along with quantitative electron microscopic analysis in control (postmortem samples from subjects with no signs of neurological disorders) and epileptic (surgically removed from patients with intractable temporal lobe epilepsy) hippocampal tissue. Quantitative PCR measurements revealed that CB(1) cannabinoid receptor mRNA was downregulated to one-third of its control value in epileptic hippocampus. Likewise, the cannabinoid receptor-interacting protein-1a mRNA was decreased, whereas 1b isoform levels were unaltered. Expression of diacylglycerol lipase-alpha, an enzyme responsible for 2-arachidonoylglycerol synthesis, was also reduced by approximately 60%, whereas its related beta isoform levels were unchanged. Expression level of N-acyl-phosphatidylethanolamine-hydrolyzing phospholipase D and fatty acid amide hydrolase, metabolic enzymes of anandamide, and 2-arachidonoylglycerol's degrading enzyme monoacylglycerol lipase did not change. The density of CB(1) immunolabeling was also decreased in epileptic hippocampus, predominantly in the dentate gyrus, where quantitative electron microscopic analysis did not reveal changes in the ratio of CB(1)-positive GABAergic boutons, but uncovered robust reduction in the fraction of CB(1)-positive glutamatergic axon terminals. These findings show that a neuroprotective machinery involving endocannabinoids is impaired in epileptic human hippocampus and imply that downregulation of CB(1) receptors and related molecular components of the endocannabinoid system may facilitate the deleterious effects of increased network excitability.
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Abstract
Modulation of neurotransmitter release by G-protein-coupled receptors (GPCRs) is a prominent presynaptic mechanism for regulation of synaptic transmission. Activation of GPCRs located at the presynaptic terminal can decrease the probability of neurotransmitter release. This presynaptic depression involves activation of Gi/o-type G-proteins that mediate different inhibitory mechanisms, including inhibition of voltage-gated calcium channels, activation of potassium channels, and direct inhibition of the vesicle fusion process. A variety of neurotransmitters and modulatory agents can activate GPCRs that produce presynaptic depression. Among these are lipid metabolites that serve as agonists for GPCRs. The discovery of endocannabinoids and their cognate receptors, including the CB1 receptor, has stimulated intense investigation into the neurophysiological roles of these lipid metabolites. It is now clear that presynaptic depression is the major physiological role for the CB1 receptor. Endocannabinoids activate this receptor mainly via a retrograde signaling process in which these compounds are synthesized in and released from postsynaptic neuronal elements, and travel back to the presynaptic terminal to act on the CB1 receptor. This retrograde endocannabinoid modulation has been implicated in short-term synaptic depression, including suppression of excitatory or inhibitory transmission induced by postsynaptic depolarization and transient synaptic depression induced by activation of postsynaptic GPCRs during agonist treatment or synaptic activation. Endocannabinoids and the CB1 receptor also play a key role in one form of long-term synaptic depression (LTD) that involves a longlasting decrease in neurotransmitter release.
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MESH Headings
- Animals
- Behavior/drug effects
- Cannabinoid Receptor Modulators/metabolism
- Cannabinoid Receptor Modulators/physiology
- Cannabinoids/metabolism
- Cannabinoids/pharmacology
- Cannabinoids/toxicity
- Endocannabinoids
- Humans
- Long-Term Potentiation/drug effects
- Long-Term Potentiation/physiology
- Neuronal Plasticity/drug effects
- Neurotransmitter Uptake Inhibitors/pharmacology
- Receptor, Cannabinoid, CB1/drug effects
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB1/physiology
- Receptors, Cannabinoid/drug effects
- Receptors, Cannabinoid/metabolism
- Receptors, Cannabinoid/physiology
- Receptors, Presynaptic/drug effects
- Receptors, Presynaptic/metabolism
- Receptors, Presynaptic/physiology
- Signal Transduction/drug effects
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Affiliation(s)
- David M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Bethesda, MD 20892-9411, USA.
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Irwin N, Hunter K, Frizzell N, Flatt PR. Antidiabetic effects of sub-chronic administration of the cannabinoid receptor (CB1) antagonist, AM251, in obese diabetic (ob/ob) mice. Eur J Pharmacol 2007; 581:226-33. [PMID: 18191122 DOI: 10.1016/j.ejphar.2007.12.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 11/07/2007] [Accepted: 12/05/2007] [Indexed: 12/01/2022]
Abstract
Recent research suggests that cannabinoid CB1 receptor antagonism reduces appetite and body weight gain. The present study was designed to assess the sub-chronic effects of the selective cannabinoid CB1 receptor antagonist, AM251 (N-(Piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide), in young ob/ob mice. Pair-fed animals were used as additional controls. Daily injection of AM251 (6 mg/kg body weight) for 18 days significantly (P<0.05) decreased daily and 18-day cumulative food intake. The corresponding body weight change did not achieve significance and values were not different from pair-fed mice. Non-fasting plasma glucose was decreased (P<0.05) from day 10 onwards by AM251 treatment. The glycaemic response to intraperitoneal glucose was correspondingly improved (P<0.05) in AM251 treated mice. In keeping with this, insulin sensitivity was enhanced (P<0.05) compared to controls. Furthermore, adipose mRNA levels of acetyl-CoA carboxylase 1 were significantly (P<0.05) reduced by 18 days AM251 treatment. There were no differences in either non-fasting or glucose-stimulated insulin release. Pair-feeding had broadly similar metabolic effects to AM251 treatment apart from increased (P<0.01) locomotor activity which was only observed in AM251 treated ob/ob mice. These data indicate that sub-chronic antagonism of the cannabinoid CB1 receptor by daily treatment with AM251 counters aspects of the hyperphagia-related impairment of ob/ob mouse metabolism. Such effects seem predominantly mediated by restriction of energy intake.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, United Kingdom.
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Amantea D, Spagnuolo P, Bari M, Fezza F, Mazzei C, Tassorelli C, Morrone LA, Corasaniti MT, Maccarrone M, Bagetta G. Modulation of the endocannabinoid system by focal brain ischemia in the rat is involved in neuroprotection afforded by 17beta-estradiol. FEBS J 2007; 274:4464-775. [PMID: 17666109 DOI: 10.1111/j.1742-4658.2007.05975.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Endogenous levels of the endocannabinoid anandamide, and the activities of the synthesizing and hydrolyzing enzymes, i.e. N-acylphosphatidylethanolamine-hydrolyzing phospholipase D and fatty acid amide hydrolase, respectively, were determined in the cortex and the striatum of rats subjected to transient middle cerebral artery occlusion. Anandamide content was markedly increased ( approximately 3-fold over controls; P < 0.01) in the ischemic striatum after 2 h of middle cerebral artery occlusion, but not in the cortex, and this elevation was paralleled by increased activity of N-acylphosphatidylethanolamine-hydrolyzing phospholipase D ( approximately 1.7-fold; P < 0.01), and reduced activity ( approximately 0.6-fold; P < 0.01) and expression ( approximately 0.7-fold; P < 0.05) of fatty acid amide hydrolase. These effects of middle cerebral artery occlusion were further potentiated by 1 h of reperfusion, whereas anandamide binding to type 1 cannabinoid and type 1 vanilloid receptors was not affected significantly by the ischemic insult. Additionally, the cannabinoid type 1 receptor antagonist SR141716, but not the receptor agonist R-(+)-WIN55,212-2, significantly reduced (33%; P < 0.05) cerebral infarct volume detected 22 h after the beginning of reperfusion. A neuroprotective intraperitoneal dose of 17beta-estradiol (0.20 mg x kg(-1)) that reduced infarct size by 43% also minimized the effect of brain ischemia on the endocannabinoid system, in an estrogen receptor-dependent manner. In conclusion, we show that the endocannabinoid system is implicated in the pathophysiology of transient middle cerebral artery occlusion-induced brain damage, and that neuroprotection afforded by estrogen is coincident with a re-establishment of anandamide levels in the ischemic striatum through a mechanism that needs to be investigated further.
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Affiliation(s)
- Diana Amantea
- Department of Pharmacobiology and University Center for the Study of Adaptive Disorder and Headache (UCADH), Section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, Rende (CS), Italy
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Khaspekov LG, Bobrov MY. The endocannabinoid system and its protective role in ischemic and cytotoxic injuries of brain neurons. NEUROCHEM J+ 2007. [DOI: 10.1134/s1819712407020018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Falenski KW, Blair RE, Sim-Selley LJ, Martin BR, DeLorenzo RJ. Status epilepticus causes a long-lasting redistribution of hippocampal cannabinoid type 1 receptor expression and function in the rat pilocarpine model of acquired epilepsy. Neuroscience 2007; 146:1232-44. [PMID: 17433556 PMCID: PMC2617754 DOI: 10.1016/j.neuroscience.2007.01.065] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 12/21/2006] [Accepted: 01/21/2007] [Indexed: 11/19/2022]
Abstract
Activation of the cannabinoid type 1 (CB1) receptor, a major G-protein-coupled receptor in brain, acts to regulate neuronal excitability and has been shown to mediate the anticonvulsant effects of cannabinoids in several animal models of seizure, including the rat pilocarpine model of acquired epilepsy. However, the long-term effects of status epilepticus on the expression and function of the CB1 receptor have not been described. Therefore, this study was initiated to evaluate the effect of status epilepticus on CB1 receptor expression, binding, and G-protein activation in the rat pilocarpine model of acquired epilepsy. Using immunohistochemistry, we demonstrated that status epilepticus causes a unique "redistribution" of hippocampal CB1 receptors, consisting of specific decreases in CB1 immunoreactivity in the dense pyramidal cell layer neuropil and dentate gyrus inner molecular layer, and increases in staining in the CA1-3 strata oriens and radiatum. In addition, this study demonstrates that the redistribution of CB1 receptor expression results in corresponding functional changes in CB1 receptor binding and G-protein activation using [3H] R+-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazin-yl](1-napthalen-yl)methanone mesylate (WIN55,212-2) and agonist-stimulated [35S]GTPgammaS autoradiography, respectively. The redistribution of CB1 receptor-mediated [35S]GTPgammaS binding was 1) attributed to an altered maximal effect (Emax) of WIN55,212-2 to stimulate [35S]GTPgammaS binding, 2) reversed by the CB1 receptor antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride (SR141716A), 3) confirmed by the use of other CB1 receptor agonists, and 4) not reproduced in other G-protein-coupled receptor systems examined. These results demonstrate that status epilepticus causes a unique and selective reorganization of the CB1 receptor system that persists as a permanent hippocampal neuronal plasticity change associated with the development of acquired epilepsy.
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Affiliation(s)
- K. W. Falenski
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - R. E. Blair
- Department of Neurology, Virginia Commonwealth University, PO, Box 980599, Richmond, VA 23298, USA
| | - L. J. Sim-Selley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - B. R. Martin
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - R. J. DeLorenzo
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
- Department of Neurology, Virginia Commonwealth University, PO, Box 980599, Richmond, VA 23298, USA
- Correspondence to: R. J. DeLorenzo, Department of Neurology, PO, Box 980599, Richmond, VA 23298, USA. Tel: +1-804-828-8969; fax: +1-804-828-6432. E-mail address: (R. J. DeLorenzo)
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Mitrirattanakul S, López-Valdés HE, Liang J, Matsuka Y, Mackie K, Faull KF, Spigelman I. Bidirectional alterations of hippocampal cannabinoid 1 receptors and their endogenous ligands in a rat model of alcohol withdrawal and dependence. Alcohol Clin Exp Res 2007; 31:855-67. [PMID: 17386072 DOI: 10.1111/j.1530-0277.2007.00366.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The hippocampus is strongly implicated in memory processes and contains high concentrations of both cannabinoid receptors and their endogenous ligands. Chronic alcohol consumption impairs a variety of cognitive and performance tasks, including memory and learning. As the activation of cannabinoid receptors by their endogenous ligands modulates hippocampal neurotransmission, we hypothesized that the impaired memory and learning in alcoholism may be due to alterations in the hippocampal endocannabinoid system. METHODS We used the rat chronic intermittent ethanol (CIE) model for alcohol withdrawal and dependence which involves intermittent episodes of ethanol intoxication (60 doses) and withdrawal (approximating binge drinking episodes in humans). We measured the levels of cannabinoid 1 receptor (CB1R) protein (Western blot using a C-terminal-directed antibody), CB1R mRNA (real-time RT-PCR), CB1R localization (immunocytochemistry), tissue levels of the endocannabinoids N-arachidonoylethanolamine/anandamide (AEA) and 2-arachidonoylglycerol (2-AG), and function (patch-clamp recordings of depolarization-induced suppression of inhibition (DSI), as well as effects of CB1R agonist WIN 55,212-2 on inhibitory currents) in the hippocampus of CIE rats and their saline-treated controls. RESULTS Results were obtained in saline and CIE-treated rats after 2 and 40 days of withdrawal (DW) from their respective treatments. In 2 DW CIE rats, CB1R mRNA and protein levels were decreased by 27% (p<0.05) compared with saline controls. Surprisingly, in 40 DW CIE rats, CB1R mRNA increased by 100% and protein increased by 21%, confirmed by immunohistochemistry. Hippocampal [2-AG] increased in both 2 and 40 DW CIE rats; [AEA] increased only at 40 DW. Hippocampal DSI of CIE rats was significantly reduced at 2 DW but not at 40 DW. The CB1R agonist WIN 55,212-2 (0.5 microM) produced a significantly greater decrease in the frequency of spontaneous inhibitory currents from saline-treated rats compared with CIE rats at 2 DW, but not at 40 DW. CONCLUSIONS These data demonstrate that CIE treatment and withdrawal transiently down-regulates hippocampal CB1 Rs followed by a long-term up-regulation, including increased levels of endogenous cannabinoids. These findings are consistent with our hypothesis and suggest that long-term up-regulation of hippocampal CB1Rs may contribute to the long-term cognitive impairments in alcoholism. The data further suggest that the effectiveness of CB1R blockade in decreasing alcohol consumption may be greater after protracted abstinence from alcohol.
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Affiliation(s)
- Somsak Mitrirattanakul
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, California 90095-1668, USA
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Abstract
Increased endocannabinoid (EC) system activity promotes excessive food intake and obesity in animals and humans. The EC system regulates food intake and hedonic reward through central mechanisms located within the hypothalamus and limbic forebrain. In rodent models, cannabinoid1 (CB1) receptor blockade reduces appetite and weight and prevents obesity and insulin resistance. The EC system also regulates food intake and metabolic factors through peripheral CB1 receptors located at multiple sites throughout the body, including adipose tissue, skeletal muscle, liver, and the gastrointestinal (GI) tract. In rodent models, CB1 receptor antagonists act in the liver to decrease lipogenesis, act in the GI tract to increase satiety, and function in adipose tissue to normalize adiponectin levels and reduce fat storage. The CB1 receptor antagonist rimonabant has been shown to reduce food intake and improve metabolic parameters, such as insulin resistance and fatty liver, in animal models of obesity. In preliminary human studies, upregulation of the EC system has been linked to obesity through mechanisms that include high-fat diet, insulin resistance, and genetic malfunction of an EC inactivation enzyme. Evidence suggests that CB1 receptor blockade is a novel therapeutic strategy that addresses the underlying mechanisms of both obesity and cardiometabolic risk.
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Affiliation(s)
- Stephen C Woods
- Obesity Research Center at the University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
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Deshpande LS, Blair RE, Ziobro JM, Sombati S, Martin BR, DeLorenzo RJ. Endocannabinoids block status epilepticus in cultured hippocampal neurons. Eur J Pharmacol 2006; 558:52-9. [PMID: 17174949 PMCID: PMC2617750 DOI: 10.1016/j.ejphar.2006.11.030] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Revised: 11/09/2006] [Accepted: 11/13/2006] [Indexed: 11/29/2022]
Abstract
Status epilepticus is a serious neurological disorder associated with a significant morbidity and mortality. Antiepileptic drugs such as diazepam, phenobarbital and phenytoin are the mainstay of status epilepticus treatment. However, over 20% of status epilepticus cases are refractory to the initial treatment with two or more antiepileptic drugs. Endocannabinoids have been implicated as playing an important role in regulating seizure activity and seizure termination. This study evaluated the effects of the major endocannabinoids methanandamide and 2-arachidonylglycerol (2-AG) on status epilepticus in the low-Mg(2+) hippocampal neuronal culture model. Status epilepticus in this model was resistant to treatment with phenobarbital and phenytoin. Methanandamide and 2-AG inhibited status epilepticus in a dose-dependent manner with an EC(50) of 145+/-4.15 nM and 1.68+/-0.19 microM, respectively. In addition, the anti-status epilepticus effects of methanandamide and 2-AG were mediated by activation of the cannabinoid CB(1) receptor since they were blocked by the cannabinoid CB(1) receptor antagonist AM251. These results provide the first evidence that the endocannabinoids, methanandamide and 2-AG, are effective inhibitors of refractory status epilepticus in the hippocampal neuronal culture model and indicate that regulating the endocannabinoid system may provide a novel therapeutic approach for treating refractory status epilepticus.
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Affiliation(s)
- Laxmikant S. Deshpande
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
| | - Robert E. Blair
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
| | - Julie M. Ziobro
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
| | - Sompong Sombati
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
| | - Billy R. Martin
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
| | - Robert J. DeLorenzo
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
- Department of Molecular Biophysics and Biochemistry, Virginia Commonwealth University, Richmond, Virginia 23298, USA
- Corresponding author. Virginia Commonwealth University, School of Medicine, PO Box 980599, Richmond, VA 23298, USA. Tel.: +1 804 828 8969; fax: +1 804 828 6432. E-mail address: (R.J. DeLorenzo)
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Takahashi KA, Castillo PE. The CB1 cannabinoid receptor mediates glutamatergic synaptic suppression in the hippocampus. Neuroscience 2006; 139:795-802. [PMID: 16527424 DOI: 10.1016/j.neuroscience.2006.01.024] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/13/2006] [Accepted: 01/26/2006] [Indexed: 11/23/2022]
Abstract
Cannabinoids have profound effects on synaptic function and behavior. Of the two cloned cannabinoid receptors, cannabinoid receptor 1 (CB1) is widely distributed in the CNS and accounts for most of the neurological effects of cannabinoids, while cannabinoid receptor 2 (CB2) expression in the CNS is very limited. The presence of additional receptors [i.e. cannabinoid receptor 3 (CB3)] is suggested by growing evidence of cannabinoid effects that are not mediated by CB1 or CB2. The most direct functional evidence for a CB3 comes from a study in hippocampus where deletion of CB1 was shown to have no effect on cannabinoid-mediated suppression of the excitatory synapse between Schaffer collateral/commissural fibers and CA1 pyramidal cells [Novel cannabinoid-sensitive receptor mediates inhibition of glutamatergic synaptic transmission in the hippocampus. Neuroscience 106:1-4]. In contrast, we report here that in extracellular field recordings, the cannabinoid agonist WIN 55,212-2 (5 microM) had no effect on Schaffer collateral/commissural fiber-CA1 pyramidal cell (Sch-CA1) synaptic transmission in slices from two independently made cannabinoid receptor 1-/- lines [Zimmer et al 1999 and Ledent et al 1999] while strongly suppressing Sch-CA1 synaptic transmission in CB1+/+ mice of the background strains. Also, we observed robust cannabinoid-mediated suppression of the Sch-CA1 synapse in pure C57BL/6 mice, contradicting a recent report that cannabinoid suppression of this synapse is absent in this strain [Hoffman AF, Macgill AM, Smith D, Oz M, Lupica CR (2005) Species and strain differences in the expression of a novel glutamate-modulating cannabinoid receptor in the rodent hippocampus. Eur J Neurosci 22:2387-2391]. Our results strongly suggest that cannabinoid-induced suppression of the Sch-CA1 synapse is mediated by CB1. Non-canonical cannabinoid receptors do not seem to play a major role in inhibiting transmitter release at this synapse.
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Affiliation(s)
- K A Takahashi
- Department of Neuroscience, Albert Einstein College of Medicine of Yeshiva University, Kennedy Center Room 703, 1410 Pelham Parkway South, Bronx, NY 10461, USA
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Lozovaya N, Yatsenko N, Beketov A, Tsintsadze T, Burnashev N. Glycine receptors in CNS neurons as a target for nonretrograde action of cannabinoids. J Neurosci 2006; 25:7499-506. [PMID: 16107637 PMCID: PMC6725404 DOI: 10.1523/jneurosci.0977-05.2005] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
At many central synapses, endocannabinoids released by postsynaptic cells act retrogradely on presynaptic G-protein-coupled cannabinoid receptors to inhibit neurotransmitter release. Here, we demonstrate that cannabinoids may directly affect the functioning of inhibitory glycine receptor (GlyR) channels. In isolated hippocampal pyramidal and Purkinje cerebellar neurons, endogenous cannabinoids anandamide and 2-arachidonylglycerol, applied at physiological concentrations, inhibited the amplitude and altered the kinetics of rise time, desensitization, and deactivation of the glycine-activated current (I(Gly)) in a concentration-dependent manner. These effects of cannabinoids were observed in the presence of cannabinoid CB1/CB3, vanilloid receptor 1 antagonists, and the G-protein inhibitor GDPbetaS, suggesting a direct action of cannabinoids on GlyRs. The effect of cannabinoids on I(Gly) desensitization was strongly voltage dependent. We also demonstrate that, in the presence of a GABA(A) receptor antagonist, GlyRs may contribute to the generation of seizure-like activity induced by short bursts (seven stimuli) of high-frequency stimulation of inputs to hippocampal CA1 region, because this activity was diminished by selective GlyR antagonists (strychnine and ginkgolides B and J). The GlyR-mediated rhythmic activity was also reduced by cannabinoids (anandamide) in the presence of a CB1 receptor antagonist. These results suggest that the direct inhibition of GlyRs by endocannabinoids can modulate the hippocampal network activity.
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Affiliation(s)
- Natalia Lozovaya
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01204 Kiev, Ukraine
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Schneider U, Seifert J, Karst M, Schlimme J, Cimander K, Müller-Vahl KR. [The endogenous cannabinoid system. Therapeutic implications for neurologic and psychiatric disorders]. DER NERVENARZT 2006; 76:1062, 1065-6, 1068-72 passim. [PMID: 15776259 DOI: 10.1007/s00115-005-1888-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
For about 5,000 years, cannabis has been used as a therapeutic agent. There has been growing interest in the medical use of cannabinoids. This is based on the discovery that cannabinoids act with specific receptors (CB1 and CB2). CB1 receptors are located in specific brain areas (e.g. cerebellum, basal ganglia, and hippocampus) and CB2 receptors on cells of the immune system. Endogenous ligands of the cannabinoid receptors were also discovered (e.g. anandamids). Many physiologic processes are modulated by the two subtypes of cannabinoid receptor: motor functions, memory, appetite, and pain. These innovative neurobiologic/pharmacologic findings could possibly lead to the use of synthetic and natural cannabinoids as therapeutic agents in various areas. Until now, cannabinoids were used as antiemetic agents in chemotherapy-induced emesis and in patients with HIV-wasting syndrome. Evidence suggests that cannabinoids may prove useful in some other diseases, e.g. movement disorders such as Gilles de la Tourette's syndrome, multiple sclerosis, and pain. These new findings also explain the acute adverse effects following cannabis use.
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Affiliation(s)
- U Schneider
- Abt. Klinische Psychiatrie und Psychotherapie, Medizinische Hochschule Hannover, Deutschland.
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Hoffman AF, Macgill AM, Smith D, Oz M, Lupica CR. Species and strain differences in the expression of a novel glutamate-modulating cannabinoid receptor in the rodent hippocampus. Eur J Neurosci 2006; 22:2387-91. [PMID: 16262678 PMCID: PMC1351024 DOI: 10.1111/j.1460-9568.2005.04401.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel, non-CB1 cannabinoid receptor has been defined by the persistence of inhibition of glutamatergic EPSPs by the cannabinoid receptor agonist WIN55,212-2 in mice lacking the cloned CB1 receptor (CB1-/-) (Hajos et al., 2001). This novel receptor was also distinguished from CB1 by its sensitivity to the antagonist SR141716A and its insensitivity to the antagonist AM251 (Hajos & Freund, 2002). We have chosen to refer to this putative receptor as CBsc due to its identification on Schaffer collateral axon terminals in the hippocampus. We examined properties of CBsc receptors in Sprague Dawley (SD) rats and two strains of wild-type (WT) mice (C57BL/6J and CD1) used as backgrounds for two independent lines of CB1-/- mice (Ledent et al., 1999; Zimmer et al., 1999). The inhibition of synaptic glutamate release by WIN55,212-2 was observed in hippocampal slices from WT CD1 mice and SD rats but was absent in WT C57 mice. We also found that AM251 and SR141716A antagonized the effect of WIN55,212-2 in hippocampal slices from CD1 mice and SD rats demonstrating a lack of selectivity of these ligands for CB1 and CBsc receptors in these animals. The results indicate that the glutamate-modulating CBsc cannabinoid receptor is present in the hippocampi of CD1 mice and SD rats but not in C57BL/6J mice. Thus, we have identified animal models that may permit the study of cannabinoids independently of the novel CBsc receptor (C57CB1+/+), the CBsc receptor independently of the cloned CB1 receptor (CD1CB1-/-), or in the absence of both receptors (C57CB1-/-).
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Affiliation(s)
- Alexander F. Hoffman
- Neurophysiology Section, Cellular Neurobiology Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA
| | - Alice M. Macgill
- Neurophysiology Section, Cellular Neurobiology Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA
- Oberlin College Neuroscience Department, Oberlin, OH, USA
| | - Dennison Smith
- Oberlin College Neuroscience Department, Oberlin, OH, USA
| | - Murat Oz
- Neurophysiology Section, Cellular Neurobiology Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA
| | - Carl R. Lupica
- Neurophysiology Section, Cellular Neurobiology Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA
- Correspondence: Dr Carl R. Lupica, as above. E-mail:
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Abstract
The CB1 cannabinoid receptor is widely distributed in the central and peripheral nervous system. Within the neuron, the CB1 receptor is often localised in axon terminals, and its activation leads to inhibition of transmitter release. The consequence is inhibition of neurotransmission via a presynaptic mechanism. Inhibition of glutamatergic, GABAergic, glycinergic, cholinergic, noradrenergic and serotonergic neurotransmission has been observed in many regions of the central nervous system. In the peripheral nervous system, CB1 receptor-mediated inhibition of adrenergic, cholinergic and sensory neuroeffector transmission has been frequently observed. It is characteristic for the ubiquitous operation of CB1 receptor-mediated presynaptic inhibition that antagonistic components of functional systems (for example, the excitatory and inhibitory inputs of the same neuron) are simultaneously inhibited by cannabinoids. Inhibition of voltage-dependent calcium channels, activation of potassium channels and direct interference with the synaptic vesicle release mechanism are all implicated in the cannabinoid-evoked inhibition of transmitter release. Many presynaptic CB1 receptors are subject to an endogenous tone, i.e. they are constitutively active and/or are continuously activated by endocannabinoids. Compared with the abundant data on presynaptic inhibition by cannabinoids, there are only a few examples for cannabinoid action on the somadendritic parts of neurons in situ.
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Affiliation(s)
- B Szabo
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Albertstrasse 25, 79104 Freiburg, Germany.
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Slanina KA, Schweitzer P. Inhibition of cyclooxygenase-2 elicits a CB1-mediated decrease of excitatory transmission in rat CA1 hippocampus. Neuropharmacology 2005; 49:653-9. [PMID: 15936781 DOI: 10.1016/j.neuropharm.2005.04.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 04/19/2005] [Accepted: 04/21/2005] [Indexed: 10/25/2022]
Abstract
Cannabinoid receptor (CB1) ligands decrease excitatory and inhibitory transmission in the hippocampus, but the influence of endogenously formed cannabinoids (eCBs) on basal excitatory transmission remains uncertain. Here, we investigated the influence of eCBs on synaptic transmission in CA1 hippocampus using the slice preparation. Blockade of CB1 with the selective receptor antagonists SR141716 (rimonabant) or AM251 augmented synaptic responses evoked upon stimulation of the Schaffer collaterals. This effect persisted in the presence of bicuculline or CGP55845 to block GABA(A) or GABA(B) receptors, revealing a tonic eCB influence on excitatory transmission. Selective inhibition of cyclooxygenase-2 (COX-2) with meloxicam or NS-398 decreased excitatory responses partly in a CB1-dependent manner, independently of GABA(A) transmission. Paired-pulse paradigms suggested a presynaptic CB1 mechanism to decrease glutamate release. Inhibition of COX-1 or other routes of eCB degradation did not affect synaptic transmission. We conclude that COX-2 regulates the formation of CB1 ligands that decrease hippocampal excitatory transmission.
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Affiliation(s)
- Kristen A Slanina
- Department of Neuropharmacology, CVN 12, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Gamber KM, Macarthur H, Westfall TC. Cannabinoids augment the release of neuropeptide Y in the rat hypothalamus. Neuropharmacology 2005; 49:646-52. [PMID: 15949823 DOI: 10.1016/j.neuropharm.2005.04.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 04/15/2005] [Accepted: 04/21/2005] [Indexed: 11/29/2022]
Abstract
Little is known about the mechanism of action behind the orexigenic activity of cannabinoids. Neuropeptide Y (NPY) is one of the most potent orexigenic factors and is a key mediator in the hypothalamic control of food intake. We examined the effect of cannabinoids on NPY release using a rat hypothalamic explant model. The cannabinoid agonists anandamide (AEA) and CP55,940 both significantly augmented resting and KCl-evoked NPY release. AM251, a cannabinoid receptor antagonist, blocked the augmentation of NPY release elicited by AEA and CP55,940. Additionally, AM251 administered alone, in the absence of exogenous cannabinoid agonists, inhibited NPY release demonstrating the role of endogenous cannabinoids in NPY release. Combined, these findings demonstrate that cannabinoids augment NPY release in the hypothalamus and that this may be a potential mechanism behind the orexigenic activity of cannabinoids.
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Affiliation(s)
- Kevin M Gamber
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, 1402 South Grand Boulevard, Saint Louis, MO 63104, USA
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Abstract
ABSTRACT The medicinal use of components of Cannabis sativa (marijuana) has been studied around the world. Some of these components may have anti-convulsive properties, though the reports are controversial, and sometimes come from single case reports and clinical anecdotes. Because of ethical aspects, as some of the components of cannabis have psychotropic effects, this is a very important issue. New researches have demonstrated that some components of cannabis that don't have psychotropic action may play a role in controlling seizures. This paper reviews the relation between epilepsy and the components of cannabis sativa.
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Melis M, Pistis M, Perra S, Muntoni AL, Pillolla G, Gessa GL. Endocannabinoids mediate presynaptic inhibition of glutamatergic transmission in rat ventral tegmental area dopamine neurons through activation of CB1 receptors. J Neurosci 2004; 24:53-62. [PMID: 14715937 PMCID: PMC6729571 DOI: 10.1523/jneurosci.4503-03.2004] [Citation(s) in RCA: 374] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The endogenous cannabinoid system has been shown to play a crucial role in controlling neuronal excitability and synaptic transmission. In this study we investigated the effects of a cannabinoid receptor (CB-R) agonist WIN 55,212-2 (WIN) on excitatory synaptic transmission in the rat ventral tegmental area (VTA). Whole-cell patch clamp recordings were performed from VTA dopamine (DA) neurons in an in vitro slice preparation. WIN reduced both NMDA and AMPA EPSCs, as well as miniature EPSCs (mEPSCs), and increased the paired-pulse ratio, indicating a presynaptic locus of its action. We also found that WIN-induced effects were dose-dependent and mimicked by the CB1-R agonist HU210. Furthermore, two CB1-R antagonists, AM281 and SR141716A, blocked WIN-induced effects, suggesting that WIN modulates excitatory synaptic transmission via activation of CB1-Rs. Our additional finding that both AM281 and SR141716A per se increased NMDA EPSCs suggests that endogenous cannabinoids, released from depolarized postsynaptic neurons, might act retrogradely on presynaptic CB1-Rs to suppress glutamate release. Hence, we report that a type of synaptic modulation, previously termed depolarization-induced suppression of excitation (DSE), is present also in the VTA as a calcium-dependent phenomenon, blocked by both AM281 and SR141716A, and occluded by WIN. Importantly, DSE was partially blocked by the D2DA antagonist eticlopride and enhanced by the D2DA agonist quinpirole without changing the presynaptic cannabinoid sensitivity. These results indicate that the two pathways work in a cooperative manner to release endocannabinoids in the VTA, where they play a role as retrograde messengers for DSE via CB1-Rs.
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Affiliation(s)
- Miriam Melis
- Centre of Excellence, Neurobiology of Addiction, University of Cagliari, Monserrato, 09042 Italy.
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Lees G, Dougalis A. Differential effects of the sleep-inducing lipid oleamide and cannabinoids on the induction of long-term potentiation in the CA1 neurons of the rat hippocampus in vitro. Brain Res 2004; 997:1-14. [PMID: 14715144 DOI: 10.1016/j.brainres.2003.10.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cannabinoids have been shown to impair cognition in vivo and block long-term potentiation (LTP), a candidate experimental model of learning and memory in vitro, via cannabinoid receptor (CB1) activation. cis-Oleamide (cOA) is an endogenous sleep-inducing lipid with putative cannabinomimetic properties. We hypothesise that cOA is cannabinomimetic and perform a comparative study with synthetic and endogenous cannabinoids on their effects on synaptic conditioning via two different patterns of stimulation in the hippocampal slice. CB1 agonists, R(+)-WIN55212-2 and anandamide, but not cOA blocked high frequency stimulation (HFS)-LTP. R(+)-WIN55212-2 and cOA (stereoselectively) attenuated responses to theta-burst-LTP, while anandamide did not. The anandamide transport inhibitor, AM404, attenuated HFS-LTP, an effect reversed by the CB1 receptor antagonist SR141716A but not mimicked by the vanilloid receptor agonist capsaicin. TFNO, an inhibitor of fatty acid amide hydrolase (FAAH), the enzyme responsible for degrading anandamide, failed to block HFS-LTP alone or in combination with cOA. On the contrary, this combination was as effective as cOA on its own in attenuating theta-burst-LTP. cOA effects on theta-burst-LTP were prevented in the presence of the GABA(A) receptor blocker picrotoxin, but not by pretreatment with SR141716A. These findings suggest that cOA neither directly activates CB1 receptors nor acts via the proposed "entourage" effect [Nature 389 (1997) 25] to increase titres of anandamide through FAAH inhibition. The selective effects of cOA on theta-burst-conditioning may reflect modulation of GABAergic transmission. Anandamide uptake inhibition, but not blockade of FAAH, effectively increases synaptic concentrations of endocannabinoids.
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Affiliation(s)
- George Lees
- Sunderland Pharmacy School, School of Health, Natural and Social Sciences, University of Sunderland, Wharncliffe Street, Sunderland, SR1 3SD, UK.
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