1
|
Jalaiei A, Asadi MR, Daneshmandpour Y, Rezazadeh M, Ghafouri-Fard S. Clinical, molecular, physiologic, and therapeutic feature of patients with CHRNA4 and CHRNB2 deficiency: A systematic review. J Neurochem 2024. [PMID: 39193833 DOI: 10.1111/jnc.16200] [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: 05/05/2024] [Revised: 07/03/2024] [Accepted: 07/26/2024] [Indexed: 08/29/2024]
Abstract
The α4β2 nAChRs are crucial ion channels that control neurotransmitter release and play a role in various physiologic and pathologic processes. CHRNA4 encodes the α4-nAChRs, while CHRNB2 encodes the β2-nAChRs. Recent studies have found different variants of α4β2-nAChRs in individuals with conditions such as AD, ADHD, ALS, PD, and brain abnormalities. We conducted a scoping review following a six-stage methodology structure and adhering to PRISMA guidelines. We systematically reviewed articles using relevant keywords up to October 2, 2023. In this summary, we cover the clinical symptoms reported, the genes and protein structure of CHRNA4 and CHRNB2, mutations in these genes, inheritance patterns, the functional impact of mutations and polymorphisms in CHRNA4 and CHRNB2, and the epidemiology of these diseases. Recent research indicates that nAChRs may play a significant role in neurodegenerative disorders, possibly impacting neuronal function through yet undiscovered regulatory pathways. Studying how nAChRs interact with disease-related aggregates in neurodegenerative conditions may lead to new treatment options for these disorders.
Collapse
Affiliation(s)
- Abbas Jalaiei
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Reza Asadi
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yousef Daneshmandpour
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Maryam Rezazadeh
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| |
Collapse
|
2
|
Xiao W, Li P, Kong F, Kong J, Pan A, Long L, Yan X, Xiao B, Gong J, Wan L. Unraveling the Neural Circuits: Techniques, Opportunities and Challenges in Epilepsy Research. Cell Mol Neurobiol 2024; 44:27. [PMID: 38443733 PMCID: PMC10914928 DOI: 10.1007/s10571-024-01458-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024]
Abstract
Epilepsy, a prevalent neurological disorder characterized by high morbidity, frequent recurrence, and potential drug resistance, profoundly affects millions of people globally. Understanding the microscopic mechanisms underlying seizures is crucial for effective epilepsy treatment, and a thorough understanding of the intricate neural circuits underlying epilepsy is vital for the development of targeted therapies and the enhancement of clinical outcomes. This review begins with an exploration of the historical evolution of techniques used in studying neural circuits related to epilepsy. It then provides an extensive overview of diverse techniques employed in this domain, discussing their fundamental principles, strengths, limitations, as well as their application. Additionally, the synthesis of multiple techniques to unveil the complexity of neural circuits is summarized. Finally, this review also presents targeted drug therapies associated with epileptic neural circuits. By providing a critical assessment of methodologies used in the study of epileptic neural circuits, this review seeks to enhance the understanding of these techniques, stimulate innovative approaches for unraveling epilepsy's complexities, and ultimately facilitate improved treatment and clinical translation for epilepsy.
Collapse
Affiliation(s)
- Wenjie Xiao
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Peile Li
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Fujiao Kong
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Jingyi Kong
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoxin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Jiaoe Gong
- Department of Neurology, Hunan Children's Hospital, Changsha, Hunan Province, China.
| | - Lily Wan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China.
| |
Collapse
|
3
|
Fukuyama K, Motomura E, Okada M. Age-Dependent Activation of Purinergic Transmission Contributes to the Development of Epileptogenesis in ADSHE Model Rats. Biomolecules 2024; 14:204. [PMID: 38397441 PMCID: PMC10886636 DOI: 10.3390/biom14020204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
To explore the developmental processes of epileptogenesis/ictogenesis, this study determined age-dependent functional abnormalities associated with purinergic transmission in a genetic rat model (S286L-TG) of autosomal-dominant sleep-related hypermotor epilepsy (ADSHE). The age-dependent fluctuations in the release of ATP and L-glutamate in the orbitofrontal cortex (OFC) were determined using microdialysis and ultra-high-performance liquid chromatography with mass spectrometry (UHPLC-MS). ATP release from cultured astrocytes was also determined using UHPLC-MS. The expressions of P2X7 receptor (P2X7R), connexin 43, phosphorylated-Akt and phosphorylated-Erk were determined using capillary immunoblotting. No functional abnormalities associated with purinergic transmission could be detected in the OFC of 4-week-old S286L-TG and cultured S286L-TG astrocytes. However, P2X7R expression, as well as basal and P2X7R agonist-induced ATP releases, was enhanced in S286L-TG OFC in the critical ADSHE seizure onset period (7-week-old). Long-term exposure to a modest level of P2X7R agonist, which could not increase astroglial ATP release, for 14 d increased the expressions of P2X7R and connexin 43 and the signaling of Akt and Erk in astrocytes, and it enhanced the sensitivity of P2X7R to its agonists. Akt but not Erk increased P2X7R expression, whereas both Akt and Erk increased connexin 43 expression. Functional abnormalities, enhanced ATP release and P2X7R expression were already seen before the onset of ADSHE seizure in S286L-TG. Additionally, long-term exposure to the P2X7R agonist mimicked the functional abnormalities associated with purinergic transmission in astrocytes, similar to those in S286L-TG OFC. Therefore, these results suggest that long-term modestly enhanced purinergic transmission and/or activated P2X7R are, at least partially, involved in the development of the epileptogenesis of ADSHE, rather than that of ictogenesis.
Collapse
Affiliation(s)
| | | | - Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (E.M.)
| |
Collapse
|
4
|
Fukuyama K, Motomura E, Okada M. Age-Dependent Activation of Pannexin1 Function Contributes to the Development of Epileptogenesis in Autosomal Dominant Sleep-related Hypermotor Epilepsy Model Rats. Int J Mol Sci 2024; 25:1619. [PMID: 38338895 PMCID: PMC10855882 DOI: 10.3390/ijms25031619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
To explore the processes of epileptogenesis/ictogenesis, this study determined the age-dependent development of the functional abnormalities in astroglial transmission associated with pannexin1-hemichannel using a genetic rat model of autosomal dominant sleep-related hypermotor epilepsy (ADSHE) named 'S286L-TG'. Pannexin1 expression in the plasma membrane of primary cultured cortical astrocytes and the orbitofrontal cortex (OFC), which is an ADSHE focus region, were determined using capillary immunoblotting. Astroglial D-serine releases induced by artificial high-frequency oscillation (HFO)-evoked stimulation, the removal of extracellular Ca2+, and the P2X7 receptor agonist (BzATP) were determined using ultra-high performance liquid chromatography (UHPLC). The expressions of pannexin1 in the plasma membrane fraction of the OFC in S286L-TG at four weeks old were almost equivalent when compared to the wild type. The pannexin1 expression in the OFC of the wild type non-statistically decreased age-dependently, whereas that in S286L-TG significantly increased age-dependently, resulting in relatively increasing pannexin1 expression from the 7- (at the onset of interictal discharge) and 10-week-old (after the ADSHE seizure onset) S286L-TG compared to the wild type. However, no functional abnormalities of astroglial pannexin1 expression or D-serine release through the pannexin1-hemichannels from the cultured astrocytes of S286L-TG could be detected. Acutely HFO-evoked stimulation, such as physiological ripple burst (200 Hz) and epileptogenic fast ripple burst (500 Hz), frequency-dependently increased both pannexin1 expression in the astroglial plasma membrane and astroglial D-serine release. Neither the selective inhibitors of pannexin1-hemichannel (10PANX) nor connexin43-hemichannel (Gap19) affected astroglial D-serine release during the resting stage, whereas HFO-evoked D-serine release was suppressed by both inhibitors. The inhibitory effect of 10PANX on the ripple burst-evoked D-serine release was more predominant than that of Gap19, whereas fast ripple burst-evoked D-serine release was predominantly suppressed by Gap19 rather than 10PANX. Astroglial D-serine release induced by acute exposure to BzATP was suppressed by 10PANX but not by Gap19. These results suggest that physiological ripple burst during the sleep spindle plays important roles in the organization of some components of cognition in healthy individuals, but conversely, it contributes to the initial development of epileptogenesis/ictogenesis in individuals who have ADSHE vulnerability via activation of the astroglial excitatory transmission associated with pannexin1-hemichannels.
Collapse
Affiliation(s)
| | | | - Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (E.M.)
| |
Collapse
|
5
|
Li H, Guo A, Salgado M, Sáez JC, Lau CG. The connexin hemichannel inhibitor D4 produces rapid antidepressant-like effects in mice. J Neuroinflammation 2023; 20:191. [PMID: 37599352 PMCID: PMC10440914 DOI: 10.1186/s12974-023-02873-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/14/2023] [Indexed: 08/22/2023] Open
Abstract
Depression is a common mood disorder characterized by a range of clinical symptoms, including prolonged low mood and diminished interest. Although many clinical and animal studies have provided significant insights into the pathophysiology of depression, current treatment strategies are not sufficient to manage this disorder. It has been suggested that connexin (Cx)-based hemichannels are candidates for depression intervention by modifying the state of neuroinflammation. In this study, we investigated the antidepressant-like effect of a recently discovered selective Cx hemichannel inhibitor, a small organic molecule called D4. We first showed that D4 reduced hemichannel activity following systemic inflammation after LPS injections. Next, we found that D4 treatment prevented LPS-induced inflammatory response and depressive-like behaviors. These behavioral effects were accompanied by reduced astrocytic activation and hemichannel activity in depressive-like mice induced by repeated low-dose LPS challenges. D4 treatment also reverses depressive-like symptoms in mice subjected to chronic restraint stress (CRS). To test whether D4 broadly affected neural activity, we measured c-Fos expression in depression-related brain regions and found a reduction in c-Fos+ cells in different brain regions. D4 significantly normalized CRS-induced hypoactivation in several brain regions, including the hippocampus, entorhinal cortex, and lateral septum. Together, these results indicate that blocking Cx hemichannels using D4 can normalize neuronal activity and reduce depressive-like symptoms in mice by reducing neuroinflammation. Our work provides evidence of the antidepressant-like effect of D4 and supports glial Cx hemichannels as potential therapeutic targets for depression.
Collapse
Affiliation(s)
- Huanhuan Li
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Anni Guo
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Magdiel Salgado
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, 2381850, Valparaíso, Chile
| | - Juan C Sáez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, 2381850, Valparaíso, Chile
| | - Chunyue Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China.
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China.
| |
Collapse
|
6
|
Therapeutic Potential and Limitation of Serotonin Type 7 Receptor Modulation. Int J Mol Sci 2023; 24:ijms24032070. [PMID: 36768393 PMCID: PMC9916679 DOI: 10.3390/ijms24032070] [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: 01/06/2023] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/21/2023] Open
Abstract
Although a number of mood-stabilising atypical antipsychotics and antidepressants modulate serotonin type 7 receptor (5-HT7), the detailed contributions of 5-HT7 function to clinical efficacy and pathophysiology have not been fully understood. The mood-stabilising antipsychotic agent, lurasidone, and the serotonin partial agonist reuptake inhibitor, vortioxetine, exhibit higher binding affinity to 5-HT7 than other conventional antipsychotics and antidepressants. To date, the initially expected rapid onset of antidepressant effects-in comparison with conventional antidepressants or mood-stabilising antipsychotics-due to 5-HT7 inhibition has not been observed with lurasidone and vortioxetine; however, several clinical studies suggest that 5-HT7 inhibition likely contributes to quality of life of patients with schizophrenia and mood disorders via the improvement of cognition. Furthermore, recent preclinical studies reported that 5-HT7 inhibition might mitigate antipsychotic-induced weight gain and metabolic complication by blocking other monoamine receptors. Further preclinical studies for the development of 5-HT7 modulation against neurodevelopmental disorders and neurodegenerative diseases have been ongoing. To date, various findings from various preclinical studies indicate the possibility that 5-HT7 modifications can provide two independent strategies. The first is that 5-HT7 inhibition ameliorates the dysfunction of inter-neuronal transmission in mature networks. The other is that activation of 5-HT7 can improve transmission dysfunction due to microstructure abnormality in the neurotransmission network-which could be unaffected by conventional therapeutic agents-via modulating intracellular signalling during the neurodevelopmental stage or via loss of neural networks with aging. This review attempts to describe the current and novel clinical applications of 5-HT7 modulation based on preclinical findings.
Collapse
|
7
|
Schmiedhofer P, Vogel FD, Koniuszewski F, Ernst M. Cys-loop receptors on cannabinoids: All high? Front Physiol 2022; 13:1044575. [PMID: 36439263 PMCID: PMC9682269 DOI: 10.3389/fphys.2022.1044575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 10/24/2022] [Indexed: 11/10/2022] Open
Abstract
Endocannabinoids (eCBS) are endogenously derived lipid signaling molecules that serve as tissue hormones and interact with multiple targets, mostly within the endocannabinoid system (ECS). The ECS is a highly conserved regulatory system involved in homeostatic regulation, organ formation, and immunomodulation of chordates. The term “cannabinoid” evolved from the distinctive class of plant compounds found in Cannabis sativa, an ancient herb, due to their action on CB1 and CB2 receptors. CB1/2 receptors are the primary targets for eCBs, but their effects are not limited to the ECS. Due to the high interest and extensive research on the ECS, knowledge on its constituents and physiological role is substantial and still growing. Crosstalk and multiple targeting of molecules are common features of endogenous and plant compounds. Cannabimimetic molecules can be divided according to their origin, natural or synthetic, including phytocannabinoids (pCB’s) or synthetic cannabinoids (sCB’s). The endocannabinoid system (ECS) consists of receptors, transporters, enzymes, and signaling molecules. In this review, we focus on the effects of cannabinoids on Cys-loop receptors. Cys-loop receptors belong to the class of membrane-bound pentameric ligand gated ion channels, each family comprising multiple subunits. Mammalians possess GABA type A receptors (GABAAR), glycine receptors (GlyR), serotonin receptors type 3 (5-HT3R), and nicotinic acetylcholine receptors (nAChR). Several studies have shown different modulatory effects of CBs on multiple members of the Cys-loop receptor family. We highlight the existing knowledge, especially on subunits and protein domains with conserved binding sites for CBs and their possible pharmacological and physiological role in epilepsy and in chronic pain. We further discuss the potential for cannabinoids as first line treatments in epilepsy, chronic pain and other neuropsychiatric conditions, indicated by their polypharmacology and therapeutic profile.
Collapse
Affiliation(s)
- Philip Schmiedhofer
- SBR Development Holding, Vienna, Austria
- *Correspondence: Philip Schmiedhofer, ; Margot Ernst,
| | - Florian Daniel Vogel
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Filip Koniuszewski
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Margot Ernst
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University Vienna, Vienna, Austria
- *Correspondence: Philip Schmiedhofer, ; Margot Ernst,
| |
Collapse
|
8
|
Fukuyama K, Okada M. Brivaracetam and Levetiracetam Suppress Astroglial L-Glutamate Release through Hemichannel via Inhibition of Synaptic Vesicle Protein. Int J Mol Sci 2022; 23:ijms23094473. [PMID: 35562864 PMCID: PMC9101419 DOI: 10.3390/ijms23094473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/18/2022] [Accepted: 04/18/2022] [Indexed: 02/07/2023] Open
Abstract
To explore the pathophysiological mechanisms of antiseizure and adverse behavioural/psychiatric effects of brivaracetam and levetiracetam, in the present study, we determined the effects of brivaracetam and levetiracetam on astroglial L-glutamate release induced by artificial high-frequency oscillation (HFO) bursts using ultra-high-performance liquid chromatography. Additionally, the effects of brivaracetam and levetiracetam on protein expressions of connexin43 (Cx43) and synaptic vesicle protein 2A (SV2A) in the plasma membrane of primary cultured rat astrocytes were determined using a capillary immunoblotting system. Acutely artificial fast-ripple HFO (500 Hz) burst stimulation use-dependently increased L-glutamate release through Cx43-containing hemichannels without affecting the expression of Cx43 or SV2A in the plasma membrane, whereas acute physiological ripple HFO (200 Hz) stimulation did not affect astroglial L-glutamate release or expression of Cx43 or SV2A. Contrarily, subchronic ripple HFO and acute pathological fast-ripple HFO (500 Hz) stimulations use-dependently increased L-glutamate release through Cx43-containing hemichannels and Cx43 expression in the plasma membrane. Subchronic fast-ripple HFO-evoked stimulation produced ectopic expression of SV2A in the plasma membrane, but subchronic ripple HFO stimulation did not generate ectopic SV2A. Subchronic administration of brivaracetam and levetiracetam concentration-dependently suppressed fast-ripple HFO-induced astroglial L-glutamate release and expression of Cx43 and SV2A in the plasma membrane. In contrast, subchronic ripple HFO-evoked stimulation induced astroglial L-glutamate release, and Cx43 expression in the plasma membrane was inhibited by subchronic levetiracetam administration, but was not affected by brivaracetam. These results suggest that brivaracetam and levetiracetam inhibit epileptogenic fast-ripple HFO-induced activated astroglial transmission associated with hemichannels. In contrast, the inhibitory effect of therapeutic-relevant concentrations of levetiracetam on physiological ripple HFO-induced astroglial responses probably contributes to the adverse behavioural/psychiatric effects of levetiracetam.
Collapse
|
9
|
Fukuyama K, Motomura E, Shiroyama T, Okada M. Impact of 5-HT7 receptor inverse agonism of lurasidone on monoaminergic tripartite synaptic transmission and pathophysiology of lower risk of weight gain. Biomed Pharmacother 2022; 148:112750. [PMID: 35219120 DOI: 10.1016/j.biopha.2022.112750] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 11/25/2022] Open
Abstract
A part of atypical antipsychotics exert mood-stabilising effects via modulation of various monoamine receptors and intracellular signalling. Recent pharmacodynamic studies suggested that tripartite-synaptic transmission can be involved in pathophysiology of mood-disorders, schizophrenia, their associated cognitive impairments, and several adverse-reactions to atypical antipsychotics. Therefore, to explore mechanisms underlying antidepressive mood-stabilising and antipsychotic effects of lurasidone, we determined concentration-dependent effects of acute and subchronic lurasidone administrations on astroglial L-glutamate release, and expression of connexin43, ERK, AKT, adenosine monophosphate activated protein kinase (AMPK), 5-HT1A (5-HT1AR) and 5-HT7 (5-HT7R) receptors in cultured astrocytes using ultra-high-pressure liquid-chromatography with mass-spectrometry and capillary-immunoblotting systems. Therapeutically-relevant lurasidone concentration suppressed astroglial L-glutamate release through activated connexin43-containing hemichannel by decreasing connexin43 expression in plasma-membrane. Subchronic lurasidone administration downregulated 5-HT1AR and 5-HT7R in astroglial plasma-membrane concentration-dependently. Subchronic lurasidone administration attenuated ERK and AMPK signallings concentration-dependently without affecting AKT signalling. These results suggest that effects of subchronic lurasidone administration on astroglial L-glutamate release, 5-HT receptor, and intracellular signalling are similar to vortioxetine and different from mood-stabilising atypical antipsychotics, clozapine. Therefore, inhibitory effects of subchronic lurasidone administration on astroglial L-glutamate release through activated connexin43-containing hemichannel probably contribute to pathophysiology of antidepressive mood-stabilising effects of lurasidone. Furthermore, inhibitory effects of subchronic lurasidone administration on ERK and AMPK activities (without affecting AKT activity) induced by downregulation of 5-HT7R could result in clinical advantages of lurasidone, lower risk of weight gain.
Collapse
Affiliation(s)
- Kouji Fukuyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| | - Eishi Motomura
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| | - Takashi Shiroyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| | - Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| |
Collapse
|
10
|
Effects of an Atypical Antipsychotic, Zotepine, on Astroglial L-Glutamate Release through Hemichannels: Exploring the Mechanism of Mood-Stabilising Antipsychotic Actions and Antipsychotic-Induced Convulsion. Pharmaceuticals (Basel) 2021; 14:ph14111116. [PMID: 34832898 PMCID: PMC8625878 DOI: 10.3390/ph14111116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
Accumulating neuropsychopharmacological evidence has suggested that functional abnormalities of astroglial transmission and protein kinase B (Akt) contribute to the pathophysiology and/or pathomechanisms of several neuropsychiatric disorders, such as epilepsy, schizophrenia, affective disorders and antipsychotic-induced convulsions. Therefore, to explore the pathophysiology of mood-stabilising antipsychotics and the proconvulsive actions of atypical antipsychotics, the present study determined the effects of a mood-stabilising, atypical, antipsychotic agent, zotepine (ZTP), on astroglial L-glutamate release and the expression of connexin43 (Cx43) protein in cortical, primary, cultured astrocytes using ultra-high-pressure liquid chromatography and capillary immunoblotting systems. Both acute and subchronic administrations of therapeutically relevant concentrations of ZTP did not affect astroglial L-glutamate release or Cx43 expression in plasma membranes; however, chronic administration of a therapeutically relevant concentration of ZTP increased astroglial L-glutamate release and Cx43 expression in the plasma membrane. Subchronic administrations of a supratherapeutic concentration of ZTP enhanced astroglial L-glutamate release and Cx43 expression in the plasma membrane, whereas acute administration of a supratherapeutic concentration of ZTP enhanced astroglial L-glutamate release without affecting Cx43 expression. These stimulatory effects of ZTP on astroglial L-glutamate release through activated hemichannels and Cx43 trafficking to the astroglial plasma membrane were suppressed by the Akt inhibitor. These results suggest that ZTP enhances astroglial L-glutamate release in a concentration-dependent and time-dependent manner due to the enhanced function of astroglial hemichannels, probably via activation of Akt signalling. Therefore, the enhanced astroglial L-glutamatergic transmission induced by ZTP is, at least partially, involved in the mood-stabilising antipsychotic and proconvulsive actions of ZTP.
Collapse
|
11
|
Distinct Effects of Escitalopram and Vortioxetine on Astroglial L-Glutamate Release Associated with Connexin43. Int J Mol Sci 2021; 22:ijms221810013. [PMID: 34576176 PMCID: PMC8468507 DOI: 10.3390/ijms221810013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/20/2022] Open
Abstract
It has been established that enhancement of serotonergic transmission contributes to improvement of major depression; however, several post-mortem studies and experimental depression rodent models suggest that functional abnormalities of astrocytes play important roles in the pathomechanisms/pathophysiology of mood disorders. Direct effects of serotonin (5-HT) transporter inhibiting antidepressants on astroglial transmission systems has never been assessed in this context. Therefore, to explore the effects of antidepressants on transmission associated with astrocytes, the present study determined the effects of the selective 5-HT transporter inhibitor, escitalopram, and the 5-HT partial agonist reuptake inhibitor, vortioxetine, on astroglial L-glutamate release through activated hemichannels, and the expression of connexin43 (Cx43), type 1A (5-HT1AR) and type 7 (5-HT7R) 5-HT receptor subtypes, and extracellular signal-regulated kinase (ERK) in astrocytes using primary cultured rat cortical astrocytes in a 5-HT-free environment. Both escitalopram and 5-HT1AR antagonist (WAY100635) did not affect basal astroglial L-glutamate release or L-glutamate release through activated hemichannels. Subchronic (for seven days) administrations of vortioxetine and the 5-HT7R inverse agonist (SB269970) suppressed both basal L-glutamate release and L-glutamate release through activated hemichannels, whereas 5-HT1AR agonist (BP554) inhibited L-glutamate release through activated hemichannels, but did not affect basal L-glutamate release. In particular, WAY100635 did not affect the inhibitory effects of vortioxetine on L-glutamate release. Subchronic administration of vortioxetine, BP554 and SB269970 downregulated 5-HT1AR, 5-HT7R and phosphorylated ERK in the plasma membrane fraction, but escitalopram and WAY100635 did not affect them. Subchronic administration of SB269970 decreased Cx43 expression in the plasma membrane but did not affect the cytosol; however, subchronic administration of BP554 increased Cx43 expression in the cytosol but did not affect the plasma membrane. Subchronic vortioxetine administration increased Cx43 expression in the cytosol and decreased it in the plasma membrane. WAY100635 prevented an increased Cx43 expression in the cytosol induced by vortioxetine without affecting the reduced Cx43 expression in the plasma membrane. These results suggest that 5-HT1AR downregulation probably increases Cx43 synthesis, but 5-HT7R downregulation suppresses Cx43 trafficking to the plasma membrane. These results also suggest that the subchronic administration of therapeutic-relevant concentrations of vortioxetine inhibits both astroglial L-glutamate and Cx43 expression in the plasma membrane via 5-HT7R downregulation but enhances Cx43 synthesis in the cytosol via 5-HT1AR downregulation. This combination of the downregulation of 5-HT1AR, 5-HT7R and Cx43 in the astroglial plasma membrane induced by subchronic vortioxetine administration suggest that astrocytes is possibly involved in the pathophysiology of depression.
Collapse
|
12
|
Effects of Atypical Antipsychotics, Clozapine, Quetiapine and Brexpiprazole on Astroglial Transmission Associated with Connexin43. Int J Mol Sci 2021; 22:ijms22115623. [PMID: 34070699 PMCID: PMC8198373 DOI: 10.3390/ijms22115623] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 02/07/2023] Open
Abstract
Recently, accumulating preclinical findings suggest the possibility that functional abnormalities of tripartite synaptic transmission play important roles in the pathophysiology of schizophrenia and affective disorder. Therefore, to explore the novel mechanisms of mood-stabilizing effects associated with tripartite synaptic transmission, the present study determined the effects of mood-stabilizing antipsychotics, clozapine (CLZ), quetiapine (QTP) and brexpiprazole (BPZ), on the astroglial l-glutamate release and expression of connexin43 (Cx43) in the astroglial plasma membrane using cortical primary cultured astrocytes. Neither acute (for 120 min) nor subchronic (for 7 days) administrations of CLZ, QTP and BPZ affected basal astroglial l-glutamate release, whereas both acute and subchronic administration of CLZ, QTP and BPZ concentration-dependently enhanced astroglial l-glutamate release through activated hemichannels. Subchronic administration of therapeutic-relevant concentration of valproate (VPA), a histone deacetylase inhibiting mood-stabilizing antiepileptic drug, enhanced the stimulatory effects of therapeutic-relevant concentration of CLZ, QTP and BPZ on astroglial l-glutamate release through activated hemichannel. Subchronic administration of therapeutic-relevant concentration of CLZ, QTP and BPZ did not affect Cx43 protein expression in the plasma membrane during resting stage. After subchronic administration of VPA, acute and subchronic administration of therapeutic-relevant concentrations of CLZ increased Cx43 protein expression in the plasma membrane. Both acute administrations of therapeutic-relevant concentrations of QTP and BPZ did not affect, but subchronic administrations enhanced Cx43 protein expression in the astroglial plasma membrane. Furthermore, protein kinase B (Akt) inhibitor suppressed the stimulatory effects of CLZ and QTP, but did not affect Cx43 protein expression in the astroglial plasma membrane. These results suggest that three mood-stabilizing atypical antipsychotics, CLZ, QTP and BPZ enhance tripartite synaptic glutamatergic transmission due to enhancement of astroglial Cx43 containing hemichannel activities; however, the Cx43 activating mechanisms of these three mood-stabilizing antipsychotics were not identical. The enhanced astroglial glutamatergic transmission induced by CLZ, QTP and BPZ is, at least partially, involved in the actions of these three mood-stabilizing antipsychotics.
Collapse
|
13
|
Chronic Administrations of Guanfacine on Mesocortical Catecholaminergic and Thalamocortical Glutamatergic Transmissions. Int J Mol Sci 2021; 22:ijms22084122. [PMID: 33923533 PMCID: PMC8073983 DOI: 10.3390/ijms22084122] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/06/2021] [Accepted: 04/14/2021] [Indexed: 01/07/2023] Open
Abstract
It has been established that the selective α2A adrenoceptor agonist guanfacine reduces hyperactivity and improves cognitive impairment in patients with attention-deficit/hyperactivity disorder (ADHD). The major mechanisms of guanfacine are considered to involve the activation of the postsynaptic α2A adrenoceptor of glutamatergic pyramidal neurons in the frontal cortex, but the effects of chronic guanfacine administration on catecholaminergic and glutamatergic transmissions associated with the orbitofrontal cortex (OFC) are yet to be clarified. The actions of guanfacine on catecholaminergic transmission, the effects of acutely local and systemically chronic (for 7 days) administrations of guanfacine on catecholamine release in pathways from the locus coeruleus (LC) to OFC, the ventral tegmental area (VTA) and reticular thalamic-nucleus (RTN), from VTA to OFC, from RTN to the mediodorsal thalamic-nucleus (MDTN), and from MDTN to OFC were determined using multi-probe microdialysis with ultra-high performance liquid chromatography. Additionally, the effects of chronic guanfacine administration on the expression of the α2A adrenoceptor in the plasma membrane fraction of OFC, VTA and LC were examined using a capillary immunoblotting system. The acute local administration of therapeutically relevant concentrations of guanfacine into the LC decreased norepinephrine release in the OFC, VTA and RTN without affecting dopamine release in the OFC. Systemically, chronic administration of therapeutically relevant doses of guanfacine for 14 days increased the basal release of norepinephrine in the OFC, VTA, RTN, and dopamine release in the OFC via the downregulation of the α2A adrenoceptor in the LC, OFC and VTA. Furthermore, systemically, chronic guanfacine administration did not affect intrathalamic GABAergic transmission, but it phasically enhanced thalamocortical glutamatergic transmission. The present study demonstrated the dual actions of guanfacine on catecholaminergic transmission-acute attenuation of noradrenergic transmission and chronic enhancement of noradrenergic transmission and thalamocortical glutamatergic transmission. These dual actions of guanfacine probably contribute to the clinical effects of guanfacine against ADHD.
Collapse
|
14
|
Okada M. Can rodent models elucidate the pathomechanisms of genetic epilepsy? Br J Pharmacol 2021; 179:1620-1639. [PMID: 33689168 PMCID: PMC9291625 DOI: 10.1111/bph.15443] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/03/2021] [Accepted: 03/04/2021] [Indexed: 12/31/2022] Open
Abstract
Autosomal dominant sleep-related hypermotor epilepsy (ADSHE; previously autosomal dominant nocturnal frontal lobe epilepsy, ADNFLE), originally reported in 1994, was the first distinct genetic epilepsy shown to be caused by CHNRA4 mutation. In the past two decades, we have identified several functional abnormalities of mutant ion channels and their associated transmissions using several experiments involving single-cell and genetic animal (rodent) models. Currently, epileptologists understand that functional abnormalities underlying epileptogenesis/ictogenesis in humans and rodents are more complicated than previously believed and that the function of mutant molecules alone cannot contribute to the development of epileptogenesis/ictogenesis but play important roles in the development of epileptogenesis/ictogenesis through formation of abnormalities in various other transmission systems before epilepsy onset. Based on our recent findings using genetic rat ADSHE models, harbouring Chrna4 mutant, corresponding to human S284L-mutant CRHNA4, this review proposes a hypothesis associated with tripartite synaptic transmission in ADSHE pathomechanisms induced by mutant ACh receptors.
Collapse
Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan
| |
Collapse
|
15
|
Okada M, Fukuyama K, Shiroyama T, Ueda Y. Brivaracetam prevents astroglial l-glutamate release associated with hemichannel through modulation of synaptic vesicle protein. Biomed Pharmacother 2021; 138:111462. [PMID: 33706129 DOI: 10.1016/j.biopha.2021.111462] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 12/11/2022] Open
Abstract
The antiepileptic/anticonvulsive action of brivaracetam is considered to occur via modulation of synaptic vesicle protein 2A (SV2A); however, the pharmacological mechanisms of action have not been fully characterised. To explore the antiepileptic/anticonvulsive mechanism of brivaracetam associated with SV2A modulation, this study determined concentration-dependent effects of brivaracetam on astroglial L-glutamate release associated with connexin43 (Cx43), tumour-necrosis factor-α (TNFα) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/glutamate receptor of rat primary cultured astrocytes using ultra-high-performance liquid chromatography. Furthermore, interaction among TNFα, elevated extracellular K+ and brivaracetam on expression of SV2A and Cx43 was determined using capillary immunoblotting. TNFα and elevated extracellular K+ predominantly enhanced astroglial L-glutamate release associated with respective AMPA/glutamate receptor and hemichannel. These effects were enhanced by a synergistic effect of TNFα and elevated extracellular K+ in combination. The activation of astroglial L-glutamate release, and expression of SV2A and Cx43 in the plasma membrane was suppressed by subchronic brivaracetam administration but were unaffected by acute administration. These results suggest that migration of SV2A to the astroglial plasma membrane by hyperexcitability activates astroglial glutamatergic transmission, perhaps via hemichannel activation. Subchronic brivaracetam administration suppressed TNFα-induced activation of AMPA/glutamate receptor and hemichannel via inhibition of ectopic SV2A. These findings suggest that combined inhibition of vesicular and ectopic SV2A functions contribute to the antiepileptic/anticonvulsive mechanism of brivaracetam action.
Collapse
Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| | - Kouji Fukuyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| | - Takashi Shiroyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| | - Yuto Ueda
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan.
| |
Collapse
|
16
|
Effects of Subchronic Administrations of Vortioxetine, Lurasidone, and Escitalopram on Thalamocortical Glutamatergic Transmission Associated with Serotonin 5-HT7 Receptor. Int J Mol Sci 2021; 22:ijms22031351. [PMID: 33572981 PMCID: PMC7866391 DOI: 10.3390/ijms22031351] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/22/2021] [Accepted: 01/27/2021] [Indexed: 02/06/2023] Open
Abstract
The functional suppression of serotonin (5-HT) type 7 receptor (5-HT7R) is forming a basis for scientific discussion in psychopharmacology due to its rapid-acting antidepressant-like action. A novel mood-stabilizing atypical antipsychotic agent, lurasidone, exhibits a unique receptor-binding profile, including a high affinity for 5-HT7R antagonism. A member of a novel class of antidepressants, vortioxetine, which is a serotonin partial agonist reuptake inhibitor (SPARI), also exhibits a higher affinity for serotonin transporter, serotonin receptors type 1A (5-HT1AR) and type 3 (5-HT3R), and 5-HT7R. However, the effects of chronic administration of lurasidone, vortioxetine, and the selective serotonin reuptake inhibitor (SSRI), escitalopram, on 5-HT7R function remained to be clarified. Thus, to explore the mechanisms underlying the clinical effects of vortioxetine, escitalopram, and lurasidone, the present study determined the effects of these agents on thalamocortical glutamatergic transmission, which contributes to emotional/mood perception, using multiprobe microdialysis and 5-HT7R expression using capillary immunoblotting. Acute local administration of a 5-HT7R agonist and antagonist into the mediodorsal thalamic nucleus (MDTN) enhanced and reduced thalamocortical glutamatergic transmission, induced by N-methyl-D-aspartate (NMDA)/glutamate receptor inhibition in the reticular thalamic nucleus (RTN). Acute local administration of a relevant therapeutic concentration of vortioxetine and lurasidone into the MDTN suppressed the thalamocortical glutamatergic transmission via 5-HT7R inhibition, whereas that of escitalopram activated 5-HT7R. Subchronic administration of effective doses of vortioxetine and lurasidone (for 7 days) reduced the thalamocortical glutamatergic transmission, but escitalopram did not affect it, whereas subchronic administration of these three agents attenuated the stimulatory effects of the 5-HT7R agonist on thalamocortical glutamatergic transmission. Subchronic administration of effective doses of vortioxetine, lurasidone, and escitalopram downregulated the 5-HT7R expression of the plasma membrane in the MDTN; the 5-HT7R downregulation induced by vortioxetine and lurasidone was observed at 3 days, but that induced by escitalopram required a longer duration of 7 days. These results indicate that chronic administration of vortioxetine, escitalopram, and lurasidone generate downregulation of 5-HT7R in the thalamus; however, the direct inhibition of 5-HT7R associated with vortioxetine and lurasidone generates more rapid downregulation than the indirect elevation of the extracellular serotonin level via serotonin transporter inhibition by escitalopram.
Collapse
|
17
|
Wan H, Wang X, Chen Y, Jiang B, Chen Y, Hu W, Zhang K, Shao X. Sleep-Related Hypermotor Epilepsy: Etiology, Electro-Clinical Features, and Therapeutic Strategies. Nat Sci Sleep 2021; 13:2065-2084. [PMID: 34803415 PMCID: PMC8598206 DOI: 10.2147/nss.s330986] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 10/21/2021] [Indexed: 12/31/2022] Open
Abstract
Sleep-related hypermotor epilepsy (SHE) is a group of clinical syndromes with heterogeneous etiologies. SHE is difficult to diagnose and treat in the early stages due to its diverse clinical manifestations and difficulties in differentiating from non-epileptic events, which seriously affect patients' quality of life and social behavior. The overall prognosis for SHE is unsatisfactory, but different etiologies affect patients' prognoses. Surgical treatment is an effective method for carefully selected patients with refractory SHE; nevertheless, preoperative assessment remains challenging because of the low sensitivity of noninvasive scalp electroencephalogram and imaging to detect abnormalities. However, through a careful analysis of semiology, the clinician can deduce the potential epileptogenic zone. This paper summarizes the research status of the background, etiology, electro-clinical features, diagnostic criteria, prognosis, and treatment of SHE to provide a more in-depth understanding of its pathophysiological mechanism, improve the accuracy in the diagnosis of this group of syndromes, and further explore more targeted therapy plans.
Collapse
Affiliation(s)
- Huijuan Wan
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China.,China National Clinical Research Center for Neurological Diseases (NCRC-ND), Beijing, People's Republic of China.,Department of Neurology, First Affiliated Hospital, Xiamen University, Xiamen, People's Republic of China
| | - Xing Wang
- Department of Neurology, Chongqing University Central Hospital, Chongqing Emergency Medical Centre, Chongqing, People's Republic of China
| | - Yiyi Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China.,China National Clinical Research Center for Neurological Diseases (NCRC-ND), Beijing, People's Republic of China
| | - Bin Jiang
- Department of Neurology, First Affiliated Hospital, Xiamen University, Xiamen, People's Republic of China
| | - Yangmei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Wenhan Hu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, People's Republic of China
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xiaoqiu Shao
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China.,China National Clinical Research Center for Neurological Diseases (NCRC-ND), Beijing, People's Republic of China
| |
Collapse
|
18
|
Okubo R, Hasegawa T, Fukuyama K, Shiroyama T, Okada M. Current Limitations and Candidate Potential of 5-HT7 Receptor Antagonism in Psychiatric Pharmacotherapy. Front Psychiatry 2021; 12:623684. [PMID: 33679481 PMCID: PMC7930824 DOI: 10.3389/fpsyt.2021.623684] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/29/2021] [Indexed: 12/13/2022] Open
Abstract
Several mood-stabilizing atypical antipsychotics and antidepressants weakly block serotonin (5-HT) receptor type-7 (5-HT7R); however, the contributions of 5-HT7R antagonism to clinical efficacy and pathophysiology are yet to be clarified. A novel mood-stabilizing antipsychotic agent, lurasidone exhibits predominant binding affinity to 5-HT7R when compared with other monoamine receptors. To date, we have failed to discover the superior clinical efficacy of lurasidone on schizophrenia, mood, or anxiety disorders when compared with conventional mood-stabilizing atypical antipsychotics; however, numerous preclinical findings have indicated the possible potential of 5-HT7R antagonism against several neuropsychiatric disorders, as well as the generation of novel therapeutic options that could not be expected with conventional atypical antipsychotics. Traditional experimental techniques, electrophysiology, and microdialysis have demonstrated that the effects of 5-HT receptor type-1A (5-HT1AR) and 5-HT7R on neurotransmission are in contrast, but the effect of 5-HT1AR is more predominant than that of 5-HT7R, resulting in an insufficient understanding of the 5-HT7R function in the field of psychopharmacology. Accumulating knowledge regarding the pharmacodynamic profiles of 5-HT7R suggests that 5-HT7R is one of the key players in the establishment and remodeling of neural development and cytoarchitecture during the early developmental stage to the mature brain, and dysfunction or modulation of 5-HT7R is linked to the pathogenesis/pathophysiology of neuropsychiatric and neurodevelopmental disorders. In this review, to explore candidate novel applications for the treatment of several neuropsychiatric disorders, including mood disorders, schizophrenia, and other cognitive disturbance disorders, we discuss perspectives of psychopharmacology regarding the effects of 5-HT7R antagonism on transmission and intracellular signaling systems, based on preclinical findings.
Collapse
Affiliation(s)
- Ruri Okubo
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Toshiki Hasegawa
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Kouji Fukuyama
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Takashi Shiroyama
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Motohiro Okada
- Division of Neuroscience, Laboratory Department of Neuropsychiatry, Graduate School of Medicine, Mie University, Tsu, Japan
| |
Collapse
|
19
|
Astroglial Connexin43 as a Potential Target for a Mood Stabiliser. Int J Mol Sci 2020; 22:ijms22010339. [PMID: 33396966 PMCID: PMC7795839 DOI: 10.3390/ijms22010339] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/24/2020] [Accepted: 12/27/2020] [Indexed: 02/06/2023] Open
Abstract
Mood disorders remain a major public health concern worldwide. Monoaminergic hypotheses of pathophysiology of bipolar and major depressive disorders have led to the development of monoamine transporter-inhibiting antidepressants for the treatment of major depression and have contributed to the expanded indications of atypical antipsychotics for the treatment of bipolar disorders. In spite of psychopharmacological progress, current pharmacotherapy according to the monoaminergic hypothesis alone is insufficient to improve or prevent mood disorders. Recent approval of esketamine for treatment of treatment-resistant depression has attracted attention in psychopharmacology as a glutamatergic hypothesis of the pathophysiology of mood disorders. On the other hand, in the last decade, accumulated findings regarding the pathomechanisms of mood disorders emphasised that functional abnormalities of tripartite synaptic transmission play important roles in the pathophysiology of mood disorders. At first glance, the enhancement of astroglial connexin seems to contribute to antidepressant and mood-stabilising effects, but in reality, antidepressive and mood-stabilising actions are mediated by more complicated interactions associated with the astroglial gap junction and hemichannel. Indeed, several depressive mood-inducing stress stimulations suppress connexin43 expression and astroglial gap junction function, but enhance astroglial hemichannel activity. On the other hand, monoamine transporter-inhibiting antidepressants suppress astroglial hemichannel activity and enhance astroglial gap junction function, whereas several non-antidepressant mood stabilisers activate astroglial hemichannel activity. Based on preclinical findings, in this review, we summarise the effects of antidepressants, mood-stabilising antipsychotics, and anticonvulsants on astroglial connexin, and then, to establish a novel strategy for treatment of mood disorders, we reveal the current progress in psychopharmacology, changing the question from "what has been revealed?" to "what should be clarified?".
Collapse
|
20
|
Astrocytic Connexin43 Channels as Candidate Targets in Epilepsy Treatment. Biomolecules 2020; 10:biom10111578. [PMID: 33233647 PMCID: PMC7699773 DOI: 10.3390/biom10111578] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
In epilepsy research, emphasis is put on exploring non-neuronal targets such as astrocytic proteins, since many patients remain pharmacoresistant to current treatments, which almost all target neuronal mechanisms. This paper reviews available data on astrocytic connexin43 (Cx43) signaling in seizures and epilepsy. Cx43 is a widely expressed transmembrane protein and the constituent of gap junctions (GJs) and hemichannels (HCs), allowing intercellular and extracellular communication, respectively. A plethora of research papers show altered Cx43 mRNA levels, protein expression, phosphorylation state, distribution and/or functional coupling in human epileptic tissue and experimental models. Human Cx43 mutations are linked to seizures as well, as 30% of patients with oculodentodigital dysplasia (ODDD), a rare genetic condition caused by mutations in the GJA1 gene coding for Cx43 protein, exhibit neurological symptoms including seizures. Cx30/Cx43 double knock-out mice show increased susceptibility to evoked epileptiform events in brain slices due to impaired GJ-mediated redistribution of K+ and glutamate and display a higher frequency of spontaneous generalized chronic seizures in an epilepsy model. Contradictory, Cx30/Cx43 GJs can traffic nutrients to high-energy demanding neurons and initiate astrocytic Ca2+ waves and hyper synchronization, thereby supporting proconvulsant effects. The general connexin channel blocker carbenoxolone and blockers from the fenamate family diminish epileptiform activity in vitro and improve seizure outcome in vivo. In addition, interventions with more selective peptide inhibitors of HCs display anticonvulsant actions. To conclude, further studies aiming to disentangle distinct roles of HCs and GJs are necessary and tools specifically targeting Cx43 HCs may facilitate the search for novel epilepsy treatments.
Collapse
|
21
|
Age-Dependent and Sleep/Seizure-Induced Pathomechanisms of Autosomal Dominant Sleep-Related Hypermotor Epilepsy. Int J Mol Sci 2020; 21:ijms21218142. [PMID: 33143372 PMCID: PMC7662760 DOI: 10.3390/ijms21218142] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 10/29/2020] [Indexed: 12/22/2022] Open
Abstract
The loss-of-function S284L-mutant α4 subunit of the nicotinic acetylcholine receptor (nAChR) is considered to contribute to the pathomechanism of autosomal dominant sleep-related hypermotor epilepsy (ADSHE); however, the age-dependent and sleep-related pathomechanisms of ADSHE remain to be clarified. To explore the age-dependent and sleep-induced pathomechanism of ADSHE, the present study determined the glutamatergic transmission abnormalities associated with α4β2-nAChR and the astroglial hemichannel in the hyperdirect and corticostriatal pathways of ADSHE model transgenic rats (S286L-TG) bearing the rat S286L-mutant Chrna4 gene corresponding to the human S284L-mutant CHRNA4 gene of ADSHE, using multiprobe microdialysis and capillary immunoblotting analyses. This study could not detect glutamatergic transmission in the corticostriatal pathway from the orbitofrontal cortex (OFC) to the striatum. Before ADSHE onset (four weeks of age), functional abnormalities of glutamatergic transmission compared to the wild-type in the cortical hyperdirect pathway, from OFC to the subthalamic nucleus (STN) in S286L-TG, could not be detected. Conversely, after ADSHE onset (eight weeks of age), glutamatergic transmission in the hyperdirect pathway of S286L-TG was enhanced compared to the wild-type. Notably, enhanced glutamatergic transmission of S286L-TG was revealed by hemichannel activation in the OFC. Expression of connexin43 (Cx43) in the OFC of S286L-TG was upregulated after ADSHE onset but was almost equal to the wild-type prior to ADSHE onset. Differences in the expression of phosphorylated protein kinase B (pAkt) before ADSHE onset between the wild-type and S286L-TG were not observed; however, after ADSHE onset, pAkt was upregulated in S286L-TG. Conversely, the expression of phosphorylated extracellular signal-regulated kinase (pErk) was already upregulated before ADSHE onset compared to the wild-type. Both before and after ADSHE onset, subchronic nicotine administration decreased and did not affect the both expression of Cx43 and pErk of respective wild-type and S286L-TG, whereas the pAkt expression of both the wild-type and S286L-TG was increased by nicotine. Cx43 expression in the plasma membrane of the primary cultured astrocytes of the wild-type was increased by elevation of the extracellular K+ level (higher than 10 mM), and the increase in Cx43 expression in the plasma membrane required pErk functions. These observations indicate that a combination of functional abnormalities, GABAergic disinhibition, and upregulated pErk induced by the loss-of-function S286L-mutant α4β2-nAChR contribute to the age-dependent and sleep-induced pathomechanism of ADSHE via the upregulation/hyperactivation of the Cx43 hemichannels.
Collapse
|
22
|
Candidate Strategies for Development of a Rapid-Acting Antidepressant Class That Does Not Result in Neuropsychiatric Adverse Effects: Prevention of Ketamine-Induced Neuropsychiatric Adverse Reactions. Int J Mol Sci 2020; 21:ijms21217951. [PMID: 33114753 PMCID: PMC7662754 DOI: 10.3390/ijms21217951] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 02/08/2023] Open
Abstract
Non-competitive N-methyl-D-aspartate/glutamate receptor (NMDAR) antagonism has been considered to play important roles in the pathophysiology of schizophrenia. In spite of severe neuropsychiatric adverse effects, esketamine (racemic enantiomer of ketamine) has been approved for the treatment of conventional monoaminergic antidepressant-resistant depression. Furthermore, ketamine improves anhedonia, suicidal ideation and bipolar depression, for which conventional monoaminergic antidepressants are not fully effective. Therefore, ketamine has been accepted, with rigorous restrictions, in psychiatry as a new class of antidepressant. Notably, the dosage of ketamine for antidepressive action is comparable to the dose that can generate schizophrenia-like psychotic symptoms. Furthermore, the psychotropic effects of ketamine precede the antidepressant effects. The maintenance of the antidepressive efficacy of ketamine often requires repeated administration; however, repeated ketamine intake leads to abuse and is consistently associated with long-lasting memory-associated deficits. According to the dissociative anaesthetic feature of ketamine, it exerts broad acute influences on cognition/perception. To evaluate the therapeutic validation of ketamine across clinical contexts, including its advantages and disadvantages, psychiatry should systematically assess the safety and efficacy of either short- and long-term ketamine treatments, in terms of both acute and chronic outcomes. Here, we describe the clinical evidence of NMDAR antagonists, and then the temporal mechanisms of schizophrenia-like and antidepressant-like effects of the NMDAR antagonist, ketamine. The underlying pharmacological rodent studies will also be discussed.
Collapse
|
23
|
Okada M, Fukuyama K, Shiroyama T, Murata M. A Working Hypothesis Regarding Identical Pathomechanisms between Clinical Efficacy and Adverse Reaction of Clozapine via the Activation of Connexin43. Int J Mol Sci 2020; 21:ijms21197019. [PMID: 32987640 PMCID: PMC7583770 DOI: 10.3390/ijms21197019] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/04/2020] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Clozapine (CLZ) is an approved antipsychotic agent for the medication of treatment-resistant schizophrenia but is also well known as one of the most toxic antipsychotics. Recently, the World Health Organization’s (WHO) global database (VigiBase) reported the relative lethality of severe adverse reactions of CLZ. Agranulocytosis is the most famous adverse CLZ reaction but is of lesser lethality compared with the other adverse drug reactions of CLZ. Unexpectedly, VigiBase indicated that the prevalence and relative lethality of pneumonia, cardiotoxicity, and seizures associated with CLZ were more serious than that of agranulocytosis. Therefore, haematological monitoring in CLZ patients monitoring system provided success in the prevention of lethal adverse events from CLZ-induced agranulocytosis. Hereafter, psychiatrists must amend the CLZ patients monitoring system to protect patients with treatment-resistant schizophrenia from severe adverse CLZ reactions, such as pneumonia, cardiotoxicity, and seizures, according to the clinical evidence and pathophysiology. In this review, we discuss the mechanisms of clinical efficacy and the adverse reactions of CLZ based on the accumulating pharmacodynamic findings of CLZ, including tripartite synaptic transmission, and we propose suggestions for amending the monitoring and medication of adverse CLZ reactions associated with pneumonia, cardiotoxicity, and seizures.
Collapse
Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (T.S.)
- Correspondence: ; Tel.: +81-59-231-5018
| | - Kouji Fukuyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (T.S.)
| | - Takashi Shiroyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (T.S.)
| | - Masahiko Murata
- National Hospital Organization Sakakibara Hospital, 777 Sakakibara, Tsu, Mie 514-1292, Japan;
| |
Collapse
|
24
|
Okada M, Fukuyama K. Interaction between Mesocortical and Mesothalamic Catecholaminergic Transmissions Associated with NMDA Receptor in the Locus Coeruleus. Biomolecules 2020; 10:biom10070990. [PMID: 32630356 PMCID: PMC7407123 DOI: 10.3390/biom10070990] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/24/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022] Open
Abstract
Noncompetitive N-methyl-D-aspartate/glutamate receptor (NMDAR) antagonists contribute to the pathophysiology of schizophrenia and mood disorders but improve monoaminergic antidepressant-resistant mood disorder and suicidal ideation. The mechanisms of the double-edged sword clinical action of NMDAR antagonists remained to be clarified. The present study determined the interaction between the NMDAR antagonist (MK801), α1 adrenoceptor antagonist (prazosin), and α2A adrenoceptor agonist (guanfacine) on mesocortical and mesothalamic catecholaminergic transmission, and thalamocortical glutamatergic transmission using multiprobe microdialysis. The inhibition of NMDAR in the locus coeruleus (LC) by local MK801 administration enhanced both the mesocortical noradrenergic and catecholaminergic coreleasing (norepinephrine and dopamine) transmissions. The mesothalamic noradrenergic transmission was also enhanced by local MK801 administration in the LC. These mesocortical and mesothalamic transmissions were activated by intra-LC disinhibition of transmission of γ-aminobutyric acid (GABA) via NMDAR inhibition. Contrastingly, activated mesothalamic noradrenergic transmission by MK801 enhanced intrathalamic GABAergic inhibition via the α1 adrenoceptor, resulting in the suppression of thalamocortical glutamatergic transmission. The thalamocortical glutamatergic terminal stimulated the presynaptically mesocortical catecholaminergic coreleasing terminal in the superficial cortical layers, but did not have contact with the mesocortical selective noradrenergic terminal (which projected terminals to deeper cortical layers). Furthermore, the α2A adrenoceptor suppressed the mesocortical and mesothalamic noradrenergic transmissions somatodendritically in the LC and presynaptically/somatodendritically in the reticular thalamic nucleus (RTN). These discrepancies between the noradrenergic and catecholaminergic transmissions in the mesocortical and mesothalamic pathways probably constitute the double-edged sword clinical action of noncompetitive NMDAR antagonists.
Collapse
|
25
|
Fukuyama K, Ueda Y, Okada M. Effects of Carbamazepine, Lacosamide and Zonisamide on Gliotransmitter Release Associated with Activated Astroglial Hemichannels. Pharmaceuticals (Basel) 2020; 13:ph13060117. [PMID: 32516974 PMCID: PMC7345221 DOI: 10.3390/ph13060117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/23/2020] [Accepted: 06/03/2020] [Indexed: 12/14/2022] Open
Abstract
Recent studies using the genetic partial epilepsy model have demonstrated that hyperfunction of astroglial hemichannels contributes to pathomechanism of epileptic seizure. Therefore, to explore the novel anticonvulsive mechanisms, the present study determined the effects of voltage-dependent Na+ channel (VDSC)-inhibiting anticonvulsants, carbamazepine (CBZ), lacosamide (LCM), and zonisamide (ZNS) on the astroglial release of l-glutamate and adenosine triphosphate (ATP). The effects of subchronic administration of therapeutic-relevant dose of three anticonvulsants on the release of l-glutamate and ATP in the orbitofrontal cortex (OFC) were determined using microdialysis. The concentration-dependent effects of acute and subchronic administrations of anticonvulsants on astroglial gliotransmitter release were determined using primary cultured astrocytes. The concentration-dependent effects of subchronic administrations of anticonvulsants on connexin43 (Cx43) expression in the plasma membrane of primary cultured astrocytes were determined using the Simple Western system. An increase in the levels of extracellular K+ resulted in a concentration-dependent increase in the astroglial release of l-glutamate and ATP. The depleted levels of extracellular Ca2+ alone did not affect astroglial gliotransmitter release but did accelerate K+-evoked gliotransmitter release via activation of astroglial hemichannels. Both non-selective hemichannel inhibitor carbenoxolone (CBX) and selective Cx43 inhibitor GAP19 prevented both gliotransmitter release through activated astroglial hemichannels and the hemichannel-activating process induced by elevation of the levels of extracellular K+ with depletion of the levels of extracellular Ca2+. ZNS subchronically decreased Cx43 expression and acutely/subchronically inhibited Cx43 hemichannel activity. LCM acutely inhibited hemichannel activity but did not subchronically affect Cx43 expression. Therapeutic-relevant concentration of CBZ did not affect hemichannel activity or Cx43 expression, but supratherapeutic concentration of CBZ decreased Cx43 expression and hemichannel activity. Therefore, the present study demonstrated the distinct effects of CBZ, LCM, and ZNS on gliotransmitter release via modulation of astroglial hemichannel function. The different features of the effects of three VDSC-inhibiting anticonvulsants on astroglial transmission associated with hemichannels, at least partially, possibly contributing to the formation of the properties of these three anticonvulsants, including the antiepileptic spectrum and adverse effects regarding mood and cognitive disturbance.
Collapse
|