1
|
Revisiting Excitotoxicity in Traumatic Brain Injury: From Bench to Bedside. Pharmaceutics 2022; 14:pharmaceutics14010152. [PMID: 35057048 PMCID: PMC8781803 DOI: 10.3390/pharmaceutics14010152] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/31/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality. Consequences vary from mild cognitive impairment to death and, no matter the severity of subsequent sequelae, it represents a high burden for affected patients and for the health care system. Brain trauma can cause neuronal death through mechanical forces that disrupt cell architecture, and other secondary consequences through mechanisms such as inflammation, oxidative stress, programmed cell death, and, most importantly, excitotoxicity. This review aims to provide a comprehensive understanding of the many classical and novel pathways implicated in tissue damage following TBI. We summarize the preclinical evidence of potential therapeutic interventions and describe the available clinical evaluation of novel drug targets such as vitamin B12 and ifenprodil, among others.
Collapse
|
2
|
Makhtar SN, Senik MH, Stevenson CW, Mason R, Halliday DM. Improved functional connectivity network estimation for brain networks using multivariate partial coherence. J Neural Eng 2020; 17:026013. [PMID: 32103827 DOI: 10.1088/1741-2552/ab7a50] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Graphical networks and network metrics are widely used to understand and characterise brain networks and brain function. These methods can be applied to a range of electrophysiological data including electroencephalography, local field potential and single unit recordings. Functional networks are often constructed using pair-wise correlation between variables. The objective of this study is to demonstrate that functional networks can be more accurately estimated using partial correlation than with pair-wise correlation. APPROACH We compared network metrics derived from unconditional and conditional graphical networks, obtained using coherence and multivariate partial coherence (MVPC), respectively. Graphical networks were constructed using coherence and MVPC estimates, and binary and weighted network metrics derived from these: node degree, path length, clustering coefficients and small-world index. MAIN RESULTS Network metrics were applied to simulated and experimental single unit spike train data. Simulated data used a 10x10 grid of simulated cortical neurons with centre-surround connectivity. Conditional network metrics gave a more accurate representation of the known connectivity: Numbers of excitatory connections had range 3-11, unconditional binary node degree had range 6-80, conditional node degree had range 2-13. Experimental data used multi-electrode array recording with 19 single-units from left and right hippocampal brain areas in a rat model for epilepsy. Conditional network analysis showed similar trends to simulated data, with lower binary node degree and longer binary path lengths compared to unconditional networks. SIGNIFICANCE We conclude that conditional networks, where common dependencies are removed through partial coherence analysis, give a more accurate representation of the interactions in a graphical network model. These results have important implications for graphical network analyses of brain networks and suggest that functional networks should be derived using partial correlation, based on MVPC estimates, as opposed to the common approach of pair-wise correlation.
Collapse
Affiliation(s)
- Siti N Makhtar
- Department of Electronic Engineering, University of York, York, United Kingdom. Author to whom any correspondence should be addressed
| | | | | | | | | |
Collapse
|
3
|
Salem F, Bahrami F, Bahari Z, Jangravi Z, Najafizadeh-Sari S. Agonists of CB1 and NMDA receptors decrease the toxic effect of organophosphorus compound paraoxon on PC12 cells. UKRAINIAN BIOCHEMICAL JOURNAL 2019. [DOI: 10.15407/ubj91.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
4
|
Lamani M, Malamas MS, Farah SI, Shukla VG, Almeida MF, Weerts CM, Anderson J, Wood JT, Farizatto KLG, Bahr BA, Makriyannis A. Piperidine and piperazine inhibitors of fatty acid amide hydrolase targeting excitotoxic pathology. Bioorg Med Chem 2019; 27:115096. [PMID: 31629610 DOI: 10.1016/j.bmc.2019.115096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/07/2019] [Accepted: 09/08/2019] [Indexed: 11/30/2022]
Abstract
FAAH inhibitors offer safety advantages by augmenting the anandamide levels "on demand" to promote neuroprotective mechanisms without the adverse psychotropic effects usually seen with direct and chronic activation of the CB1 receptor. FAAH is an enzyme implicated in the hydrolysis of the endocannabinoid N-arachidonoylethanolamine (AEA), which is a partial agonist of the CB1 receptor. Herein, we report the discovery of a new series of highly potent and selective carbamate FAAH inhibitors and their evaluation for neuroprotection. The new inhibitors showed potent nanomolar inhibitory activity against human recombinant and purified rat FAAH, were selective (>1000-fold) against serine hydrolases MGL and ABHD6 and lacked any affinity for the cannabinoid receptors CB1 and CB2. Evaluation of FAAH inhibitors 9 and 31 using the in vitro competitive activity-based protein profiling (ABPP) assay confirmed that both inhibitors were highly selective for FAAH in the brain, since none of the other FP-reactive serine hydrolases in this tissue were inhibited by these agents. Our design strategy followed a traditional SAR approach and was supported by molecular modeling studies based on known FAAH cocrystal structures. To rationally design new molecules that are irreversibly bound to FAAH, we have constructed "precovalent" FAAH-ligand complexes to identify good binding geometries of the ligands within the binding pocket of FAAH and then calculated covalent docking poses to select compounds for synthesis. FAAH inhibitors 9 and 31 were evaluated for neuroprotection in rat hippocampal slice cultures. In the brain tissue, both inhibitors displayed protection against synaptic deterioration produced by kainic acid-induced excitotoxicity. Thus, the resultant compounds produced through rational design are providing early leads for developing therapeutics against seizure-related damage associated with a variety of disorders.
Collapse
Affiliation(s)
- Manjunath Lamani
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| | - Michael S Malamas
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA.
| | - Shrouq I Farah
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| | - Vidyanand G Shukla
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| | - Michael F Almeida
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, NC 28372, USA
| | - Catherine M Weerts
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| | - Joseph Anderson
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| | - JodiAnne T Wood
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| | - Karen L G Farizatto
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, NC 28372, USA
| | - Ben A Bahr
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, NC 28372, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery and Department of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA 02155, USA
| |
Collapse
|
5
|
Shubina L, Aliev R, Kitchigina V. Endocannabinoid-dependent protection against kainic acid-induced long-term alteration of brain oscillations in guinea pigs. Brain Res 2017; 1661:1-14. [DOI: 10.1016/j.brainres.2017.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 01/12/2023]
|
6
|
Su SH, Wang YQ, Wu YF, Wang DP, Lin Q, Hai J. Cannabinoid receptor agonist WIN55,212-2 and fatty acid amide hydrolase inhibitor URB597 may protect against cognitive impairment in rats of chronic cerebral hypoperfusion via PI3K/AKT signaling. Behav Brain Res 2016; 313:334-344. [DOI: 10.1016/j.bbr.2016.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 07/03/2016] [Accepted: 07/06/2016] [Indexed: 02/06/2023]
|
7
|
Zhou J, Burkovskiy I, Yang H, Sardinha J, Lehmann C. CB2 and GPR55 Receptors as Therapeutic Targets for Systemic Immune Dysregulation. Front Pharmacol 2016; 7:264. [PMID: 27597829 PMCID: PMC4992728 DOI: 10.3389/fphar.2016.00264] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 08/05/2016] [Indexed: 11/25/2022] Open
Abstract
The endocannabinoid system (ECS) is involved in many physiological processes and has been suggested to play a critical role in the immune response and the central nervous system (CNS). Therefore, ECS modulation has potential therapeutic effects on immune dysfunctional disorders, such as sepsis and CNS injury-induced immunodeficiency syndrome (CIDS). In sepsis, excessive release of pro- and anti-inflammatory mediators results in multi-organ dysfunction, failure, and death. In CIDS, an acute CNS injury dysregulates a normally well-balanced interplay between CNS and the immune system, leading to increased patients' susceptibility to infections. In this review, we will discuss potential therapeutic modulation of the immune response in sepsis and CNS injury by manipulation of the ECS representing a novel target for immunotherapy.
Collapse
Affiliation(s)
- Juan Zhou
- Department of Anesthesia, Dalhousie UniversityHalifax, NS, Canada
- Department of Microbiology and Immunology, Dalhousie UniversityHalifax, NS, Canada
| | - Ian Burkovskiy
- Department of Anesthesia, Dalhousie UniversityHalifax, NS, Canada
- Department of Pharmacology, Dalhousie UniversityHalifax, NS, Canada
| | - Hyewon Yang
- Department of Anesthesia, Dalhousie UniversityHalifax, NS, Canada
- Department of Microbiology and Immunology, Dalhousie UniversityHalifax, NS, Canada
| | - Joel Sardinha
- Department of Anesthesia, Dalhousie UniversityHalifax, NS, Canada
| | - Christian Lehmann
- Department of Anesthesia, Dalhousie UniversityHalifax, NS, Canada
- Department of Microbiology and Immunology, Dalhousie UniversityHalifax, NS, Canada
- Department of Pharmacology, Dalhousie UniversityHalifax, NS, Canada
| |
Collapse
|
8
|
Non-parametric directionality analysis – Extension for removal of a single common predictor and application to time series. J Neurosci Methods 2016; 268:87-97. [DOI: 10.1016/j.jneumeth.2016.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/18/2016] [Accepted: 05/04/2016] [Indexed: 11/22/2022]
|
9
|
Aguilar DD, Giuffrida A, Lodge DJ. THC and endocannabinoids differentially regulate neuronal activity in the prefrontal cortex and hippocampus in the subchronic PCP model of schizophrenia. J Psychopharmacol 2016; 30:169-81. [PMID: 26510449 PMCID: PMC5252830 DOI: 10.1177/0269881115612239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cannabis use has been associated with an increased risk to develop schizophrenia as well as symptom exacerbation in patients. In contrast, clinical studies have revealed an inverse relationship between the cerebrospinal fluid levels of the endocannabinoid anandamide and symptom severity, suggesting a therapeutic potential for endocannabinoid-enhancing drugs. Indeed, preclinical studies have shown that these drugs can reverse distinct behavioral deficits in a rodent model of schizophrenia. The mechanisms underlying the differences between exogenous and endogenous cannabinoid administration are currently unknown. Using the phencyclidine (PCP) rat model of schizophrenia, we compared the effects on neuronal activity of systematic administration of delta-9-tetrahydrocannabinol (THC) with the fatty acid amide hydrolase inhibitor URB597. Specifically, we found that the inhibitory response in the prefrontal cortex to THC administration was absent in PCP-treated rats. In contrast, an augmented response to endocannabinoid upregulation was observed in the prefrontal cortex of PCP-treated rats. Interestingly, differential effects were also observed at the neuronal population level, as endocannabinoid upregulation induced opposite effects on coordinated activity when compared with THC. Such information is important for understanding why marijuana and synthetic cannabinoid use may be contraindicated in schizophrenia patients while endocannabinoid enhancement may provide a novel therapeutic approach.
Collapse
Affiliation(s)
- David D Aguilar
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | | | | |
Collapse
|
10
|
Ibeas Bih C, Chen T, Nunn AVW, Bazelot M, Dallas M, Whalley BJ. Molecular Targets of Cannabidiol in Neurological Disorders. Neurotherapeutics 2015; 12:699-730. [PMID: 26264914 PMCID: PMC4604182 DOI: 10.1007/s13311-015-0377-3] [Citation(s) in RCA: 370] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Cannabis has a long history of anecdotal medicinal use and limited licensed medicinal use. Until recently, alleged clinical effects from anecdotal reports and the use of licensed cannabinoid medicines are most likely mediated by tetrahydrocannabinol by virtue of: 1) this cannabinoid being present in the most significant quantities in these preparations; and b) the proportion:potency relationship between tetrahydrocannabinol and other plant cannabinoids derived from cannabis. However, there has recently been considerable interest in the therapeutic potential for the plant cannabinoid, cannabidiol (CBD), in neurological disorders but the current evidence suggests that CBD does not directly interact with the endocannabinoid system except in vitro at supraphysiological concentrations. Thus, as further evidence for CBD's beneficial effects in neurological disease emerges, there remains an urgent need to establish the molecular targets through which it exerts its therapeutic effects. Here, we conducted a systematic search of the extant literature for original articles describing the molecular pharmacology of CBD. We critically appraised the results for the validity of the molecular targets proposed. Thereafter, we considered whether the molecular targets of CBD identified hold therapeutic potential in relevant neurological diseases. The molecular targets identified include numerous classical ion channels, receptors, transporters, and enzymes. Some CBD effects at these targets in in vitro assays only manifest at high concentrations, which may be difficult to achieve in vivo, particularly given CBD's relatively poor bioavailability. Moreover, several targets were asserted through experimental designs that demonstrate only correlation with a given target rather than a causal proof. When the molecular targets of CBD that were physiologically plausible were considered for their potential for exploitation in neurological therapeutics, the results were variable. In some cases, the targets identified had little or no established link to the diseases considered. In others, molecular targets of CBD were entirely consistent with those already actively exploited in relevant, clinically used, neurological treatments. Finally, CBD was found to act upon a number of targets that are linked to neurological therapeutics but that its actions were not consistent withmodulation of such targets that would derive a therapeutically beneficial outcome. Overall, we find that while >65 discrete molecular targets have been reported in the literature for CBD, a relatively limited number represent plausible targets for the drug's action in neurological disorders when judged by the criteria we set. We conclude that CBD is very unlikely to exert effects in neurological diseases through modulation of the endocannabinoid system. Moreover, a number of other molecular targets of CBD reported in the literature are unlikely to be of relevance owing to effects only being observed at supraphysiological concentrations. Of interest and after excluding unlikely and implausible targets, the remaining molecular targets of CBD with plausible evidence for involvement in therapeutic effects in neurological disorders (e.g., voltage-dependent anion channel 1, G protein-coupled receptor 55, CaV3.x, etc.) are associated with either the regulation of, or responses to changes in, intracellular calcium levels. While no causal proof yet exists for CBD's effects at these targets, they represent the most probable for such investigations and should be prioritized in further studies of CBD's therapeutic mechanism of action.
Collapse
Affiliation(s)
- Clementino Ibeas Bih
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | - Tong Chen
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | | | - Michaël Bazelot
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
- GW Pharmaceuticals Ltd, Sovereign House, Vision Park, Chivers Way, Histon, Cambridge, CB24 9BZ, UK
| | - Mark Dallas
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK
| | - Benjamin J Whalley
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK.
| |
Collapse
|
11
|
Polypharmacology Shakes Hands with Complex Aetiopathology. Trends Pharmacol Sci 2015; 36:802-821. [PMID: 26434643 DOI: 10.1016/j.tips.2015.08.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 02/07/2023]
Abstract
Chronic diseases are due to deviations of fundamental physiological systems, with different pathologies being characterised by similar malfunctioning biological networks. The ensuing compensatory mechanisms may weaken the body's dynamic ability to respond to further insults and reduce the efficacy of conventional single target treatments. The multitarget, systemic, and prohomeostatic actions emerging for plant cannabinoids exemplify what might be needed for future medicines. Indeed, two combined cannabis extracts were approved as a single medicine (Sativex(®)), while pure cannabidiol, a multitarget cannabinoid, is emerging as a treatment for paediatric drug-resistant epilepsy. Using emerging cannabinoid medicines as an example, we revisit the concept of polypharmacology and describe a new empirical model, the 'therapeutic handshake', to predict efficacy/safety of compound combinations of either natural or synthetic origin.
Collapse
|
12
|
Su SH, Wu YF, Lin Q, Yu F, Hai J. Cannabinoid receptor agonist WIN55,212-2 and fatty acid amide hydrolase inhibitor URB597 suppress chronic cerebral hypoperfusion-induced neuronal apoptosis by inhibiting c-Jun N-terminal kinase signaling. Neuroscience 2015; 301:563-75. [DOI: 10.1016/j.neuroscience.2015.03.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/13/2015] [Accepted: 03/11/2015] [Indexed: 11/15/2022]
|
13
|
Guggenhuber S, Romo-Parra H, Bindila L, Leschik J, Lomazzo E, Remmers F, Zimmermann T, Lerner R, Klugmann M, Pape HC, Lutz B. Impaired 2-AG Signaling in Hippocampal Glutamatergic Neurons: Aggravation of Anxiety-Like Behavior and Unaltered Seizure Susceptibility. Int J Neuropsychopharmacol 2015; 19:pyv091. [PMID: 26232789 PMCID: PMC4772822 DOI: 10.1093/ijnp/pyv091] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/29/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Postsynaptically generated 2-arachidonoylglycerol activates the presynaptic cannabinoid type-1 receptor, which is involved in synaptic plasticity at both glutamatergic and GABAergic synapses. However, the differential function of 2-arachidonoylglycerol signaling at glutamatergic vs GABAergic synapses in the context of animal behavior has not been investigated yet. METHODS Here, we analyzed the role of 2-arachidonoylglycerol signaling selectively in hippocampal glutamatergic neurons. Monoacylglycerol lipase, the primary degrading enzyme of 2-arachidonoylglycerol, is expressed at presynaptic sites of excitatory and inhibitory neurons. By adeno-associated virus-mediated overexpression of monoacylglycerol lipase in glutamatergic neurons of the mouse hippocampus, we selectively interfered with 2-arachidonoylglycerol signaling at glutamatergic synapses of these neurons. RESULTS Genetic modification of monoacylglycerol lipase resulted in a 50% decrease in 2-arachidonoylglycerol tissue levels without affecting the content of the second major endocannabinoid anandamide. A typical electrophysiological read-out for 2-arachidonoylglycerol signaling is the depolarization-induced suppression of excitation and of inhibition. Elevated monoacylglycerol lipase levels at glutamatergic terminals selectively impaired depolarization-induced suppression of excitation, while depolarization-induced suppression of inhibition was not significantly changed. At the behavioral level, mice with impaired hippocampal glutamatergic 2-arachidonoylglycerol signaling exhibited increased anxiety-like behavior but showed no alterations in aversive memory formation and seizure susceptibility. CONCLUSION Our data indicate that 2-arachidonoylglycerol signaling selectively in hippocampal glutamatergic neurons is essential for the animal's adaptation to aversive situations.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany (Dr Guggenhuber, Dr Bindila, Dr Leschik, Dr Lomazzo, Dr Remmers, Ms Zimmermann, Ms Lerner, Dr Klugmann, and Dr Lutz); Institute of Physiology I (Neurophysiology), Westfaelische Wilhelms-University, Muenster, Germany (Drs Romo-Parra and Pape); Translational Neuroscience Facility, Department of Physiology, School of Medical Sciences, University of New South Wales, UNSW Kensington Campus, Sydney, NSW, Australia (Dr Klugmann).
| |
Collapse
|
14
|
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.
Collapse
|
15
|
Aguilar DD, Chen L, Lodge DJ. Increasing endocannabinoid levels in the ventral pallidum restore aberrant dopamine neuron activity in the subchronic PCP rodent model of schizophrenia. Int J Neuropsychopharmacol 2014; 18:pyu035. [PMID: 25539511 PMCID: PMC4332795 DOI: 10.1093/ijnp/pyu035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Schizophrenia is a debilitating disorder that affects 1% of the US population. While the exogenous administration of cannabinoids such as tetrahydrocannabinol is reported to exacerbate psychosis in schizophrenia patients, augmenting the levels of endogenous cannabinoids has gained attention as a possible alternative therapy to schizophrenia due to clinical and preclinical observations. Thus, patients with schizophrenia demonstrate an inverse relationship between psychotic symptoms and levels of the endocannabinoid anandamide. In addition, increasing endocannabinoid levels (by blockade of enzymatic degradation) has been reported to attenuate social withdrawal in a preclinical model of schizophrenia. Here we examine the effects of increasing endogenous cannabinoids on dopamine neuron activity in the sub-chronic phencyclidine (PCP) model. Aberrant dopamine system function is thought to underlie the positive symptoms of schizophrenia. METHODS Using in vivo extracellular recordings in chloral hydrate-anesthetized rats, we now demonstrate an increase in dopamine neuron population activity in PCP-treated rats. RESULTS Interestingly, endocannabinoid upregulation, induced by URB-597, was able to normalize this aberrant dopamine neuron activity. Furthermore, we provide evidence that the ventral pallidum is the site where URB-597 acts to restore ventral tegmental area activity. CONCLUSIONS Taken together, we provide preclinical evidence that augmenting endogenous cannabinoids may be an effective therapy for schizophrenia, acting in part to restore ventral pallidal activity.
Collapse
Affiliation(s)
- David D Aguilar
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, Texas (Aguilar, Drs Chen and Lodge); Departments of Physiology & Pathophysiology, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, China (Dr Chen).
| | | | | |
Collapse
|
16
|
Ma L, Wang L, Yang F, Meng XD, Wu C, Ma H, Jiang W. Disease-modifying effects of RHC80267 and JZL184 in a pilocarpine mouse model of temporal lobe epilepsy. CNS Neurosci Ther 2014; 20:905-15. [PMID: 24989980 DOI: 10.1111/cns.12302] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Patients with temporal lobe epilepsy (TLE) often suffer from comorbid psychiatric diagnoses such as depression, anxiety, or impaired cognitive performance. Endocannabinoid (eCB) signaling is a key regulator of synaptic neurotransmission and has been implicated in the mechanisms of epilepsy as well as several mood disorders and cognitive impairments. AIMS We employed a pilocarpine model of TLE in C57/BJ mice to investigate the role of eCB signaling in epileptogenesis and concomitant psychiatric comorbidities. METHODS AND RESULTS We sought to alter the neuronal levels of a known eCB receptor ligand, 2-arachidonylglycerol (2-AG), through the use of RHC80267 or JZL184. Pilocarpine-treated mice were treated with RHC80267 (1.3 μmol) or JZL184 (20 mg/kg) immediately after the termination of status epilepticus (SE), which was followed by daily treatment for the next 7 days. Our results indicated that RHC80267 treatment significantly reduced the percentage of mice suffering from spontaneous recurrent seizures (SRS) in addition to decreasing the duration of observed seizures when compared to vehicle treatment. Furthermore, RHC80267 attenuated depression and anxiety-related behaviors, improved previously impaired spatial learning and memory, and inhibited seizure-induced hippocampal neuronal loss during the chronic epileptic period. In contrast, JZL184 administration markedly increased the frequency and the duration of observed SRS, enhanced the previously impaired neuropsychological performance, and increased hippocampal damage following SE. CONCLUSIONS These findings suggest that RHC80267 treatment after the onset of SE could result in an amelioration of the effects found during the chronic epileptic period and yield an overall decrease in epileptic symptoms and comorbid conditions. Thus, alterations to endocannabinoid signaling may serve as a potential mechanism to prevent epileptogenesis and manipulation of this signaling pathway as a possible drug target.
Collapse
Affiliation(s)
- Lei Ma
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | | | | | | | | | | | | |
Collapse
|
17
|
Yang R, Cui HJ, Wang H, Wang Y, Liu JH, Li Y, Lu Y. N-Stearoyltyrosine Protects Against Glutamate-Induced Oxidative Toxicity by an Apoptosis-Inducing Factor (AIF)-Mediated Caspase-Independent Cell Death Pathway. J Pharmacol Sci 2014; 124:169-79. [DOI: 10.1254/jphs.13184fp] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
|
18
|
Naidoo V, Karanian DA, Vadivel SK, Locklear JR, Wood JT, Nasr M, Quizon PMP, Graves EE, Shukla V, Makriyannis A, Bahr BA. Equipotent inhibition of fatty acid amide hydrolase and monoacylglycerol lipase - dual targets of the endocannabinoid system to protect against seizure pathology. Neurotherapeutics 2012; 9:801-13. [PMID: 22270809 PMCID: PMC3480564 DOI: 10.1007/s13311-011-0100-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Advances in the understanding of the endogenous cannabinoid system have led to several therapeutic indications for new classes of compounds that enhance cannabinergic responses. Endocannabinoid levels are elevated during pathogenic conditions, and inhibitors of endocannabinoid inactivation promote such on-demand responses. The endocannabinoids anandamide and 2-arachidonoyl glycerol have been implicated in protective signaling against excitotoxic episodes, including seizures. To better understand modulatory pathways that can exploit such responses, we used the new generation compound AM6701 that blocks both the anandamide-deactivating enzyme fatty acid amide hydrolase (FAAH) and the 2-arachidonoyl glycerol-deactivating enzyme monoacylglycerol lipase (MAGL) with equal potency. Also studied was the structural isomer AM6702 which is 44-fold more potent for inhibiting FAAH versus MAGL. When applied before and during kainic acid (KA) exposure to cultured hippocampal slices, AM6701 protected against the resulting excitotoxic events of calpain-mediated cytoskeletal damage, loss of presynaptic and postsynaptic proteins, and pyknotic changes in neurons. The equipotent inhibitor was more effective than its close relative AM6702 at protecting against the neurodegenerative cascade assessed in the slice model. In vivo, AM6701 was also the more effective compound for reducing the severity of KA-induced seizures and protecting against behavioral deficits linked to seizure damage. Corresponding with the behavioral improvements, cytoskeletal and synaptic protection was elicited by AM6701, as found in the KA-treated hippocampal slice model. It is proposed that the influence of AM6701 on FAAH and MAGL exerts a synergistic action on the endocannabinoid system, thereby promoting the protective nature of cannabinergic signaling to offset excitotoxic brain injury.
Collapse
Affiliation(s)
- Vinogran Naidoo
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
- Department of Biology, University of North Carolina Pembroke, Pembroke, North Carolina USA
| | - David A. Karanian
- Department of Pharmaceutical Sciences and the Neurosciences Program, University of Connecticut, Storrs, Connecticut USA
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | | | - Johnathan R. Locklear
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
| | - JodiAnne T. Wood
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | - Mahmoud Nasr
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | - Pamela Marie P. Quizon
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
| | - Emily E. Graves
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
| | - Vidyanand Shukla
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | | | - Ben A. Bahr
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
- Department of Biology, University of North Carolina Pembroke, Pembroke, North Carolina USA
- Department of Pharmaceutical Sciences and the Neurosciences Program, University of Connecticut, Storrs, Connecticut USA
| |
Collapse
|
19
|
Abstract
Painful peripheral neuropathy is a dose-limiting complication of chemotherapy. Cisplatin produces a cumulative toxic effect on peripheral nerves, and 30-40% of cancer patients receiving this agent experience pain. By modeling cisplatin-induced hyperalgesia in mice with daily injections of cisplatin (1 mg/kg, i.p.) for 7 d, we investigated the anti-hyperalgesic effects of anandamide (AEA) and cyclohexylcarbamic acid 3'-carbamoyl-biphenyl-3-yl ester (URB597), an inhibitor of AEA hydrolysis. Cisplatin-induced mechanical and heat hyperalgesia were accompanied by a decrease in the level of AEA in plantar paw skin. No changes in motor activity were observed after seven injections of cisplatin. Intraplantar injection of AEA (10 μg/10 μl) or URB597 (9 μg/10 μl) transiently attenuated hyperalgesia through activation of peripheral CB₁ receptors. Co-injections of URB597 (0.3 mg/kg daily, i.p.) with cisplatin decreased and delayed the development of mechanical and heat hyperalgesia. The effect of URB597 was mediated by CB₁ receptors since AM281 (0.33 mg/kg daily, i.p.) blocked the effect of URB597. Co-injection of URB597 also normalized the cisplatin-induced decrease in conduction velocity of Aα/Aβ-fibers and reduced the increase of ATF-3 and TRPV1 immunoreactivity in dorsal root ganglion (DRG) neurons. Since DRGs are a primary site of toxicity by cisplatin, effects of cisplatin were studied on cultured DRG neurons. Incubation of DRG neurons with cisplatin (4 μg/ml) for 24 h decreased the total length of neurites. URB597 (100 nM) attenuated these changes through activation of CB₁ receptors. Collectively, these results suggest that pharmacological facilitation of AEA signaling is a promising strategy for attenuating cisplatin-associated sensory neuropathy.
Collapse
|
20
|
Caprioli A, Coccurello R, Rapino C, Di Serio S, Di Tommaso M, Vertechy M, Vacca V, Battista N, Pavone F, Maccarrone M, Borsini F. The novel reversible fatty acid amide hydrolase inhibitor ST4070 increases endocannabinoid brain levels and counteracts neuropathic pain in different animal models. J Pharmacol Exp Ther 2012; 342:188-95. [PMID: 22514334 DOI: 10.1124/jpet.111.191403] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The effect of the enol carbamate 1-biphenyl-4-ylethenyl piperidine-1-carboxylate (ST4070), a novel reversible inhibitor of fatty acid amide hydrolase (FAAH), was investigated for acute pain sensitivity and neuropathic pain in rats and mice. Brain enzymatic activity of FAAH and the endogenous levels of its substrates, anandamide (AEA; N-arachidonoylethanolamine), 2-arachidonoylglycerol (2-AG), and N-palmitoylethanolamine (PEA), were measured in control and ST4070-treated mice. ST4070 (10, 30, and 100 mg/kg) was orally administered to assess mechanical nociceptive thresholds and allodynia by using the Randall-Selitto and von Frey tests, respectively. Neuropathy was induced in rats by either the chemotherapeutic agent vincristine or streptozotocin-induced diabetes, whereas the chronic constriction injury (CCI) model was chosen to evaluate neuropathy in mice. ST4070 produced a significant increase of nociceptive threshold in rats and counteracted the decrease of nociceptive threshold in the three distinct models of neuropathic pain. In diabetic mice, ST4070 inhibited FAAH activity and increased the brain levels of AEA and PEA, without affecting that of 2-AG. The administration of ST4070 generated long-lasting pain relief compared with pregabalin and the FAAH inhibitors 1-oxo-1[5-(2-pyridyl)-2-yl]-7-phenylheptane (OL135) and cyclohexylcarbamic acid 3'-carbamoylbiphenyl-3-ylester (URB597) in CCI neuropathic mice. The antiallodynic effects of ST4070 were prevented by pretreatment with cannabinoid type 1 and cannabinoid type 2 receptor antagonists and by the selective peroxisome proliferator-activated receptor α antagonist [(2S)-2-[[(1Z)-1-methyl-3-oxo-3-[4-(trifluoromethyl)phenyl]-1-propenyl]amino]-3-[4-[2-(5-methyl-2-phenyl-4-oxazolyl)ethoxy]phenyl]propyl]-carbamic acid ethyl ester (GW6471). The administration of ST4070 generated long-lasting neuropathic pain relief compared with pregabalin and the FAAH inhibitors OL135 and URB597. Taken together, the reversible FAAH inhibitor ST4070 seems to be a promising novel therapeutic agent for the management of neuropathic pain.
Collapse
Affiliation(s)
- Antonio Caprioli
- Sigma-Tau Industrie Farmaceutiche Riunite S.p.A., Via Pontina km. 30,400, 00040 Pomezia, Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
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.
Collapse
Affiliation(s)
- Ricka D Messer
- Department of Neuroscience, University of Connecticut Health Center, Farmington,CT 06030, USA
| | | |
Collapse
|
22
|
Shohami E, Cohen-Yeshurun A, Magid L, Algali M, Mechoulam R. Endocannabinoids and traumatic brain injury. Br J Pharmacol 2012; 163:1402-10. [PMID: 21418185 DOI: 10.1111/j.1476-5381.2011.01343.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Traumatic brain injury (TBI) represents the leading cause of death in young individuals. It triggers the accumulation of harmful mediators, leading to secondary damage, yet protective mechanisms are also set in motion. The endocannabinoid (eCB) system consists of ligands, such as anandamide and 2-arachidonoyl-glycerol (2-AG), receptors (e.g. CB1, CB2), transporters and enzymes, which are responsible for the 'on-demand' synthesis and degradation of these lipid mediators. There is a large body of evidence showing that eCB are markedly increased in response to pathogenic events. This fact, as well as numerous studies on experimental models of brain toxicity, neuroinflammation and trauma supports the notion that the eCB are part of the brain's compensatory or repair mechanisms. These are mediated via CB receptors signalling pathways that are linked to neuronal survival and repair. The levels of 2-AG, the most highly abundant eCB, are significantly elevated after TBI and when administered to TBI mice, 2-AG decreases brain oedema, inflammation and infarct volume and improves clinical recovery. The role of CB1 in mediating these effects was demonstrated using selective antagonists or CB1 knockout mice. CB2 were shown in other models of brain insults to reduce white blood cell rolling and adhesion, to reduce infarct size and to improve motor function. This review is focused on the role the eCB system plays as a self-neuroprotective mechanism and its potential as a basis for the development of novel therapeutic modality for the treatment of CNS pathologies with special emphasis on TBI.
Collapse
Affiliation(s)
- Esther Shohami
- The Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Israel.
| | | | | | | | | |
Collapse
|
23
|
Goonawardena AV, Sesay J, Sexton CA, Riedel G, Hampson RE. Pharmacological elevation of anandamide impairs short-term memory by altering the neurophysiology in the hippocampus. Neuropharmacology 2011; 61:1016-25. [PMID: 21767554 DOI: 10.1016/j.neuropharm.2011.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 06/05/2011] [Accepted: 07/01/2011] [Indexed: 10/18/2022]
Abstract
In rodents, many exogenous cannabinoid agonists including Δ(9)-THC and WIN55,212-2 (WIN-2) have been shown to impair short-term memory (STM) by inhibition of hippocampal neuronal assemblies. However, the mechanisms by which endocannabinoids such as anandamide and 2-arachidonyl glycerol (2-AG) modulate STM processes are not well understood. Here the effects of anandamide on performance of a Delayed-Non-Match-to-Sample (DNMS) task (i.e. STM task) and concomitant hippocampal ensemble activity were assessed following administration of either URB597 (0.3, 3.0 mg/kg), an inhibitor of the Fatty Acid Amide Hydrolase (FAAH), AM404 (1.5, 10.0 mg/kg), a putative anandamide uptake/FAAH inhibitor, or R-methanandamide (3.0, 10.0 mg/kg), a stable analog of anandamide. Principal cells from hippocampal CA3/CA1 were recorded extracellularly by multi-electrode arrays in Long-Evans rats during DNMS task (1-30 s delays) performance and tracked throughout drug administration and recovery. Both R-methanandamide and URB597 caused dose- and delay-dependent deficits in DNMS performance with suppression of hippocampal ensemble activity during the encoding (sample) phase. R-methanandamide-induced effects were not reversed by capsaicin excluding a contribution of TRPV-1 receptors. AM404 produced subtle deficits at longer delay intervals but did not alter hippocampal neuronal activity during task-specific events. Collectively, these data indicate that endocannabinoid levels affect performance in a STM task and their pharmacological elevation beyond normal concentrations is detrimental also for the underlying physiological responses. They also highlight a specific window of memory processing, i.e. encoding, which is sensitive to cannabinoid modulation.
Collapse
Affiliation(s)
- Anushka V Goonawardena
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 271157-1083, USA
| | | | | | | | | |
Collapse
|
24
|
Goonawardena AV, Riedel G, Hampson RE. Cannabinoids alter spontaneous firing, bursting, and cell synchrony of hippocampal principal cells. Hippocampus 2011; 21:520-31. [PMID: 20101600 PMCID: PMC3126104 DOI: 10.1002/hipo.20769] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Both natural and synthetic cannabinoid receptor (e.g., CB1) agonists such as Δ(9)-THC, WIN 55,212-2 (WIN-2), and HU-210 disrupt spatial cognition presumably through the inhibition of synchrony of hippocampal ensemble firing to task-related events. Although the CB1 receptor agonist CP 55,940 also disrupts the synchronous firing of hippocampal neurons, it does not seem to affect the average firing rate. This difference is not readily explained by the chemical structure and pharmacology of the different compounds thus warranting a more detailed examination into (i) how other cannabinoids affect the spontaneous firing, bursting, and cell synchrony of hippocampal principal cells located in CA3 and CA1 subfields, and (ii) whether these effects are indeed mediated through CB1 receptors, which will be explored by the selective antagonist AM-251. Male Long-Evans rats surgically implanted with multielectrode arrays to hippocampal CA3 and CA1 were anesthetized and principal cells discharging at 0.25-6.0 Hz were isolated and "tracked" following the systemic administration of Tween-80, Δ(9)-THC (1 or 3 mg/kg) or WIN-2 (1 mg/kg) or HU-210 (100 μg/kg), and 1.5 mg/kg AM-281. All cannabinoids except for 1 mg/kg Δ(9) -THC reliably reduced average firing rates and altered "burst" characteristics, which were reversible with AM-281 for Δ(9)-THC and WIN-2 but not for HU-210. In addition, all cannabinoids disrupted intrasubfield and intersubfield ensemble synchrony of pyramidal cells, which is an effect insensitive to AM-281 and thus unlikely to be CB1 mediated. We consider these cannabinoid effects on spike timing and firing/bursting of principal hippocampal neurons carried by CB1 and non-CB1 receptors to be physiological underpinnings of the cognitive impairments inherent to cannabinoid exposure.
Collapse
Affiliation(s)
- Anushka V Goonawardena
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States
- School of Medicine and Life Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Gernot Riedel
- School of Medicine and Life Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Robert E Hampson
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States
- School of Medicine and Life Sciences, University of Aberdeen, Aberdeen, United Kingdom
| |
Collapse
|
25
|
Guggenhuber S, Monory K, Lutz B, Klugmann M. AAV vector-mediated overexpression of CB1 cannabinoid receptor in pyramidal neurons of the hippocampus protects against seizure-induced excitoxicity. PLoS One 2010; 5:e15707. [PMID: 21203567 PMCID: PMC3006205 DOI: 10.1371/journal.pone.0015707] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 11/19/2010] [Indexed: 11/19/2022] Open
Abstract
The CB1 cannabinoid receptor is the most abundant G-protein coupled receptor in the brain and a key regulator of neuronal excitability. There is strong evidence that CB1 receptor on glutamatergic hippocampal neurons is beneficial to alleviate epileptiform seizures in mouse and man. Therefore, we hypothesized that experimentally increased CB1 gene dosage in principal neurons would have therapeutic effects in kainic acid (KA)-induced hippocampal pathogenesis. Here, we show that virus-mediated conditional overexpression of CB1 receptor in pyramidal and mossy cells of the hippocampus is neuroprotective and moderates convulsions in the acute KA seizure model in mice. We introduce a recombinant adeno-associated virus (AAV) genome with a short stop element flanked by loxP sites, for highly efficient attenuation of transgene expression on the transcriptional level. The presence of Cre-recombinase is strictly necessary for expression of reporter proteins or CB1 receptor in vitro and in vivo. Transgenic CB1 receptor immunoreactivity is targeted to glutamatergic neurons after stereotaxic delivery of AAV to the dorsal hippocampus of the driver mice NEX-cre. Increased CB1 receptor protein levels in hippocampal lysates of AAV-treated Cre-mice is paralleled by enhanced cannabinoid-induced G-protein activation. KA-induced seizure severity and mortality is reduced in CB1 receptor overexpressors compared with AAV-treated control animals. Neuronal damage in the hippocampal CA3 field is specifically absent from AAV-treated Cre-transgenics, but evident throughout cortical areas of both treatment groups. Our data provide further evidence for a role of increased CB1 signaling in pyramidal hippocampal neurons as a safeguard against the adverse effects of excessive excitatory network activity.
Collapse
Affiliation(s)
- Stephan Guggenhuber
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Krisztina Monory
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail: (MK); (BL)
| | - Matthias Klugmann
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail: (MK); (BL)
| |
Collapse
|
26
|
Naidoo V, Nikas SP, Karanian DA, Hwang J, Zhao J, Wood JT, Alapafuja SO, Vadivel SK, Butler D, Makriyannis A, Bahr BA. A new generation fatty acid amide hydrolase inhibitor protects against kainate-induced excitotoxicity. J Mol Neurosci 2010; 43:493-502. [PMID: 21069475 DOI: 10.1007/s12031-010-9472-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 10/28/2010] [Indexed: 02/02/2023]
Abstract
Endocannabinoids, including anandamide (AEA), have been implicated in neuroprotective on-demand responses. Related to such a response to injury, an excitotoxic kainic acid (KA) injection (i.p.) was found to increase AEA levels in the brain. To modulate the endocannabinoid response during events of excitotoxicity in vitro and in vivo, we utilized a new generation compound (AM5206) that selectively inhibits the AEA deactivating enzyme fatty acid amide hydrolase (FAAH). KA caused calpain-mediated spectrin breakdown, declines in synaptic markers, and disruption of neuronal integrity in cultured hippocampal slices. FAAH inhibition with AM5206 protected against the neurodegenerative cascade assessed in the slice model 24 h postinsult. In vivo, KA administration induced seizures and the same neurodegenerative events exhibited in vitro. When AM5206 was injected immediately after KA in rats, the seizure scores were markedly reduced as were levels of cytoskeletal damage and synaptic protein decline. The pre- and postsynaptic proteins were protected by the FAAH inhibitor to levels comparable to those found in healthy control brains. These data support the idea that endocannabinoids are released and converge on pro-survival pathways that prevent excitotoxic progression.
Collapse
Affiliation(s)
- Vinogran Naidoo
- Biotechnology Research and Training Center, University of North Carolina Pembroke, 115 Livermore Drive, Pembroke, NC 28372-1510, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Taxidis J, Coomber B, Mason R, Owen M. Assessing cortico-hippocampal functional connectivity under anesthesia and kainic acid using generalized partial directed coherence. BIOLOGICAL CYBERNETICS 2010; 102:327-340. [PMID: 20204395 DOI: 10.1007/s00422-010-0370-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 02/08/2010] [Indexed: 05/28/2023]
Abstract
A significant challenge in modern neuroscience lies in determining the functional connectivity between discrete populations of neurones and brain regions. In this study, a variation of partial directed coherence, the generalized partial directed coherence (gPDC), along with a newly proposed critical value for gPDC, were applied on recorded local field potentials (LFPs) and single-unit activity, in order to assess information flow between medial prefrontal cortex (mPFC) and hippocampus and within the hippocampus of the rat brain, under isoflurane anesthesia and kainic acid-induced enhanced neuronal activity. Our findings suggest that, under anesthesia, there exists a continuous information flow from hippocampus towards mPFC, reversed mostly during activity bursts occurring in the mPFC. Moreover, there was a clear directional connection from the lateral towards medial dorsal hippocampus, most prominent in the beta frequency band (10-30 Hz). Kainic acid resulted in partially disrupting the reciprocal cortico-hippocampal connectivity and reversing the intra-hippocampal one. The biological implications of these findings on the effects of anesthesia and kainic acid in brain connectivity, along with implementation issues of gPDC analysis on field potentials and spike trains, are extensively discussed.
Collapse
Affiliation(s)
- Jiannis Taxidis
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
| | | | | | | |
Collapse
|
28
|
Lozovaya N, Min R, Tsintsadze V, Burnashev N. Dual modulation of CNS voltage-gated calcium channels by cannabinoids: Focus on CB1 receptor-independent effects. Cell Calcium 2009; 46:154-62. [PMID: 19682741 DOI: 10.1016/j.ceca.2009.07.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 07/18/2009] [Indexed: 01/13/2023]
Abstract
The neuromodulatory effects of cannabinoids in the central nervous system have mainly been associated with G-protein coupled cannabinoid receptor (CB1R) mediated inhibition of voltage-gated calcium channels (VGCCs). Numerous studies show, however, that cannabinoids can also modulate VGCCs independent of CB1R activation. Nevertheless, despite the fact that endocannabinoids have a nearly equal efficacy for direct and CB1R-mediated effects on VGCC, the role of the direct cannabinoid-VGCC interaction has been largely underestimated. In this review, we summarize recent studies on the modulation of different types of VGCCs by cannabinoids, highlight the evidence for and implications of the CB1R-independent modulation, and put forward the concept, that direct interaction of cannabinoids and VGCCs is as important in regulation of VGCCs function as the CB1R-mediated effects.
Collapse
Affiliation(s)
- Natalia Lozovaya
- Institut de Neurobiologie de la Méditerranée INSERM U, Marseille, France
| | | | | | | |
Collapse
|
29
|
Mason R, Cheer JF. Cannabinoid receptor activation reverses kainate-induced synchronized population burst firing in rat hippocampus. Front Integr Neurosci 2009; 3:13. [PMID: 19562087 PMCID: PMC2701678 DOI: 10.3389/neuro.07.013.2009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 06/02/2009] [Indexed: 12/01/2022] Open
Abstract
Cannabinoids have been shown to possess anticonvulsant properties in whole animal models of epilepsy. The present investigation sought to examine the effects of cannabinoid receptor activation on kainic acid (KA)-induced epileptiform neuronal excitability. Under urethane anesthesia, acute KA treatment (10 mg kg−1, i.p.) entrained the spiking mode of simultaneously recorded neurons from random firing to synchronous bursting (% change in burst rate). Injection of the high-affinity cannabinoid agonist (-)-11-hydroxy-8-tetrahydrocannabinol-dimethyl-heptyl (HU210, 100 μg kg−1, i.p.) following KA markedly reduced the burst frequency (% decrease in burst frequency) and reversed synchronized firing patterns back to baseline levels. Pre-treatment with the central cannabinoid receptor (CB1) antagonist N-piperidino-5-(4-clorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (rimonabant, SR141716A 3 mg kg−1, i.p.) completely prevented the actions of HU210. The present results indicate that cannabinoids exert their antiepileptic effects by impeding pathological synchronization of neuronal networks in the hippocampus.
Collapse
Affiliation(s)
- Rob Mason
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre Nottingham, UK
| | | |
Collapse
|
30
|
Hwang J, Adamson C, Butler D, Janero DR, Makriyannis A, Bahr BA. Enhancement of endocannabinoid signaling by fatty acid amide hydrolase inhibition: a neuroprotective therapeutic modality. Life Sci 2009; 86:615-23. [PMID: 19527737 DOI: 10.1016/j.lfs.2009.06.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 05/28/2009] [Accepted: 06/03/2009] [Indexed: 12/31/2022]
Abstract
AIMS This review posits that fatty acid amide hydrolase (FAAH) inhibition has therapeutic potential against neuropathological states including traumatic brain injury; Alzheimer's, Huntington's, and Parkinson's diseases; and stroke. MAIN METHODS This proposition is supported by data from numerous in vitro and in vivo experiments establishing metabolic and pharmacological contexts for the neuroprotective role of the endogenous cannabinoid ("endocannabinoid") system and selective FAAH inhibitors. KEY FINDINGS The systems biology of endocannabinoid signaling involves two main cannabinoid receptors, the principal endocannabinoid lipid mediators N-arachidonoylethanolamine ("anandamide") (AEA) and 2-arachidonoyl glycerol (2-AG), related metabolites, and the proteins involved in endocannabinoid biosynthesis, biotransformation, and transit. The endocannabinoid system is capable of activating distinct signaling pathways on-demand in response to pathogenic events or stimuli, thereby enhancing cell survival and promoting tissue repair. Accumulating data suggest that endocannabinoid system modulation at discrete targets is a promising pharmacotherapeutic strategy for treating various medical conditions. In particular, neuronal injury activates cannabinoid signaling in the central nervous system as an intrinsic neuroprotective response. Indirect potentiation of this salutary response through pharmacological inhibition of FAAH, an endocannabinoid-deactivating enzyme, and consequent activation of signaling pathways downstream from cannabinoid receptors have been shown to promote neuronal maintenance and function. SIGNIFICANCE This therapeutic modality has the potential to offer site- and event-specific neuroprotection under conditions where endocannabinoids are being produced as part of a physiological protective mechanism. In contrast, direct application of cannabinoid receptor agonists to the central nervous system may activate CB receptors indiscriminately and invite unwanted psychotrophic effects.
Collapse
Affiliation(s)
- Jeannie Hwang
- Department of Pharmaceutical Sciences and the Neurosciences Program, University of Connecticut, Storrs, Connecticut, USA
| | | | | | | | | | | |
Collapse
|
31
|
Falenski KW, Carter DS, Harrison AJ, Martin BR, Blair RE, DeLorenzo RJ. Temporal characterization of changes in hippocampal cannabinoid CB(1) receptor expression following pilocarpine-induced status epilepticus. Brain Res 2009; 1262:64-72. [PMID: 19368833 DOI: 10.1016/j.brainres.2009.01.036] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 01/22/2009] [Accepted: 01/23/2009] [Indexed: 02/05/2023]
Abstract
Several reports have focused on the involvement of the endocannabinoid system in hyperexcitability, particularly in seizure and epilepsy models. Our laboratory recently characterized a novel plasticity change of the cannabinoid type 1 (CB(1)) receptor in hippocampi of epileptic rats following pilocarpine-induced status epilepticus (SE). This long-term redistribution included selective layer-specific changes in CB(1) receptor expression within distinct hippocampal subregions. However, the temporal characteristics of this redistribution during the development of epilepsy had not been examined. Therefore, this study was initiated to evaluate the time course by which pilocarpine-induced SE produced changes in CB(1) receptor expression. Immunohistochemical analysis demonstrated that within 1 week following SE, there was a pronounced loss in CB(1) receptor expression throughout the hippocampus, while staining in many interneurons was preserved. By 1 month post-SE, pilocarpine-treated animals began to display epileptic seizures, and CB(1) receptor expression was characteristic of the redistribution observed in long-term epileptic rats, with decreases in CB(1) receptor immunoreactivity in the stratum pyramidale neuropil and dentate gyrus inner molecular layer, and increases in the strata oriens and radiatum of CA1-3. Observed changes in CB(1) receptor expression were confirmed at multiple time points by western blot analysis. The data indicate that overall decreases in expression following SE preempt a long-lasting CB(1) receptor redistribution, and that differential responses occur within the hippocampus to initial CB(1) receptor losses. This suggests a role for dysregulation of the endocannabinoid system during epileptogenesis and indicates that the CB(1) receptor redistribution temporally correlates with the emergence of epileptic seizures.
Collapse
Affiliation(s)
- Katherine W Falenski
- Department of Neurology, Virginia Commonwealth University, PO Box 980599, Richmond, VA 23298, USA
| | | | | | | | | | | |
Collapse
|