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Benhadda A, Delhaye C, Moutkine I, Marques X, Russeau M, Le Magueresse C, Roumier A, Lévi S, Maroteaux L. 5-HT 1A and 5-HT 2B receptor interaction and co-clustering regulate serotonergic neuron excitability. iScience 2023; 26:107401. [PMID: 37575185 PMCID: PMC10415917 DOI: 10.1016/j.isci.2023.107401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/26/2023] [Accepted: 07/12/2023] [Indexed: 08/15/2023] Open
Abstract
Many psychiatric diseases have been associated with serotonin (5-HT) neuron dysfunction. The firing of 5-HT neurons is known to be under 5-HT1A receptor-mediated autoinhibition, but functional consequences of coexpressed receptors are unknown. Using co-immunoprecipitation, BRET, confocal, and super-resolution microscopy in hippocampal and 5-HT neurons, we present evidence that 5-HT1A and 5-HT2B receptors can form heterodimers and co-cluster at the plasma membrane of dendrites. Selective agonist stimulation of coexpressed 5-HT1A and 5-HT2B receptors prevents 5-HT1A receptor internalization and increases 5-HT2B receptor membrane clustering. Current clamp recordings of 5-HT neurons revealed that 5-HT1A receptor stimulation of acute slices from mice lacking 5-HT2B receptors in 5-HT neurons increased their firing activity trough Ca2+-activated potassium channel inhibition compared to 5-HT neurons from control mice. This work supports the hypothesis that the relative expression of 5-HT1A and 5-HT2B receptors tunes the neuronal excitability of serotonergic neurons through potassium channel regulation.
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Affiliation(s)
- Amina Benhadda
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Célia Delhaye
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Imane Moutkine
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Xavier Marques
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Marion Russeau
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Corentin Le Magueresse
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Anne Roumier
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Sabine Lévi
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
| | - Luc Maroteaux
- Institut du Fer à Moulin, U1270 INSERM, Sorbonne Université, 17 rue du Fer à Moulin, 75005 Paris, France
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Anderson EM, Demis S, Wrucke B, Engelhardt A, Hearing MC. Infralimbic cortex pyramidal neuron GIRK signaling contributes to regulation of cognitive flexibility but not affect-related behavior in male mice. Physiol Behav 2021; 242:113597. [PMID: 34536435 DOI: 10.1016/j.physbeh.2021.113597] [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: 07/20/2021] [Revised: 08/30/2021] [Accepted: 09/13/2021] [Indexed: 10/20/2022]
Abstract
Dysfunction of the infralimbic cortical (ILC) region of the medial prefrontal cortex (mPFC) is thought to be an underlying factor in both affect- and cognition-related behavioral deficits that co-occur across neuropsychiatric disorders. Increasing evidence highlights pathological imbalances in prefrontal pyramidal neuron excitability and associated aberrant firing as an underlying factor in this dysfunction. G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels mediate excitability of mPFC pyramidal neurons, however the functional role of these channels in ILC-dependent regulation of behavior and pyramidal neuron excitation is unknown. The present study used a viral-cre approach in male mice harboring a 'floxed' version of the kcnj3 (Girk1) gene, to disrupt GIRK1-containing channel expression in pyramidal neurons within the ILC. Loss of GIRK1-dependent signaling increased excitability and spike firing of pyramidal neurons but did not alter affective behavior measured in an elevated plus maze, forced swim test, or progressive ratio test of motivation. Alternatively, ablation of GIRK1 impaired performance in an operant-based attentional set-shifting task designed to assess cognitive flexibility. These data highlight a unique role for GIRK1 signaling in ILC pyramidal neurons in the regulation of strategy shifting but not affect and suggest that these channels may represent a therapeutic target for treatment of cognitive deficits in neuropsychiatric disease.
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Anderson EM, Loke S, Wrucke B, Engelhardt A, Demis S, O'Reilly K, Hess E, Wickman K, Hearing MC. Suppression of pyramidal neuron G protein-gated inwardly rectifying K+ channel signaling impairs prelimbic cortical function and underlies stress-induced deficits in cognitive flexibility in male, but not female, mice. Neuropsychopharmacology 2021; 46:2158-2169. [PMID: 34158613 PMCID: PMC8505646 DOI: 10.1038/s41386-021-01063-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/25/2021] [Accepted: 06/03/2021] [Indexed: 12/11/2022]
Abstract
Imbalance in prefrontal cortical (PFC) pyramidal neuron excitation:inhibition is thought to underlie symptomologies shared across stress-related disorders and neuropsychiatric disease, including dysregulation of emotion and cognitive function. G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels mediate excitability of medial PFC pyramidal neurons, however, the functional role of these channels in mPFC-dependent regulation of affect, cognition, and cortical dynamics is unknown. We used a viral-cre approach in male and female mice harboring a "floxed" version of the kcnj3 (Girk1) gene, to disrupt GIRK1-containing channel expression in pyramidal neurons within the prelimbic cortex (PrL). In males, loss of pyramidal GIRK1-dependent signaling differentially impacted measures of affect and impaired working memory and cognitive flexibility. Unexpectedly, ablation of PrL GIRK1-dependent signaling did not impact affect or cognition in female mice. Additional studies used a model of chronic unpredictable stress (CUS) to determine the impact on PrL GIRK-dependent signaling and cognitive function. CUS exposure in male mice produced deficits in cognition that paralleled a reduction in PrL pyramidal GIRK-dependent signaling akin to viral approaches whereas CUS exposure in female mice did not alter cognitive flexibility performance. Stress-induced behavioral deficits in male mice were rescued by systemic injection of a novel, GIRK1-selective agonist, ML297. In conclusion, GIRK1-dependent signaling in male mice, but not females, is critical for maintaining optimal PrL function and behavioral control. Disruption of this inhibition may underlie stress-related dysfunction of the PrL and represent a therapeutic target for treating stress-induced deficits in affect regulation and impaired cognition that reduce quality of life.
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Affiliation(s)
- Eden M Anderson
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Steven Loke
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Benjamin Wrucke
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Annabel Engelhardt
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Skyler Demis
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Kevin O'Reilly
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Evan Hess
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - Matthew C Hearing
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA.
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Sałaciak K, Pytka K. Biased agonism in drug discovery: Is there a future for biased 5-HT 1A receptor agonists in the treatment of neuropsychiatric diseases? Pharmacol Ther 2021; 227:107872. [PMID: 33905796 DOI: 10.1016/j.pharmthera.2021.107872] [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: 02/22/2021] [Revised: 04/17/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022]
Abstract
Serotonin (5-HT) is one of the fundamental neurotransmitters that contribute to the information essential for an organism's normal, physiological function. Serotonin acts centrally and systemically. The 5-HT1A receptor is the most widespread serotonin receptor, and participates in many brain-related disorders, including anxiety, depression, and cognitive impairments. The 5-HT1A receptor can activate several different biochemical pathways and signals through both G protein-dependent and G protein-independent pathways. Preclinical experiments indicate that distinct signaling pathways in specific brain regions may be crucial for antidepressant-like, anxiolytic-like, and procognitive responses. Therefore, the development of new ligands that selectively target a particular signaling pathway(s) could open new possibilities for more effective and safer pharmacotherapy. This review discusses the current state of preclinical studies focusing on the concept of functional selectivity (biased agonism) regarding the 5-HT1A receptor and its role in antidepressant-like, anxiolytic-like, and procognitive regulation. Such work highlights not only the differential effects of targeted autoreceptors, vs. heteroreceptors, but also the importance of targeting specific downstream intracellular signaling processes, thereby enhancing favorable over unfavorable signaling activation.
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Affiliation(s)
- Kinga Sałaciak
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland
| | - Karolina Pytka
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland.
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Anderson EM, Demis S, D’Acquisto H, Engelhardt A, Hearing M. The Role of Parvalbumin Interneuron GIRK Signaling in the Regulation of Affect and Cognition in Male and Female Mice. Front Behav Neurosci 2021; 15:621751. [PMID: 33841107 PMCID: PMC8032990 DOI: 10.3389/fnbeh.2021.621751] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/19/2021] [Indexed: 11/13/2022] Open
Abstract
Pathological impairments in the regulation of affect (i.e., emotion) and flexible decision-making are commonly observed across numerous neuropsychiatric disorders and are thought to reflect dysfunction of cortical and subcortical circuits that arise in part from imbalances in excitation and inhibition within these structures. Disruptions in GABA transmission, in particular, that from parvalbumin-expressing interneurons (PVI), has been highlighted as a likely mechanism by which this imbalance arises, as they regulate excitation and synchronization of principle output neurons. G protein-gated inwardly rectifying potassium ion (GIRK/Kir3) channels are known to modulate excitability and output of pyramidal neurons in areas like the medial prefrontal cortex and hippocampus; however, the role GIRK plays in PVI excitability and behavior is unknown. Male and female mice lacking GIRK1 in PVI (Girk1flox/flox:PVcre) and expressing td-tomato in PVI (Girk1flox/flox:PVCre:PVtdtom) exhibited increased open arm time in the elevated plus-maze, while males showed an increase in immobile episodes during the forced swim test (FST). Loss of GIRK1 did not alter motivated behavior for an appetitive reward or impair overall performance in an operant-based attention set-shifting model of cognitive flexibility; however it did alter types of errors committed during the visual cue test. Unexpectedly, baseline sex differences were also identified in these tasks, with females exhibiting overall poorer performance compared to males and distinct types of errors, highlighting potential differences in task-related problem-solving. Interestingly, reductions in PVI GIRK signaling did not correspond to changes in membrane excitability but did increase action potential (AP) firing at higher current injections in PVI of males, but not females. This is the first investigation on the role that PVI GIRK-signaling has on membrane excitability, AP firing, and their role on affect and cognition together increasing the understanding of PVI cellular mechanisms and function.
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Affiliation(s)
| | | | | | | | - Matthew Hearing
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, United States
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6
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Therapeutic potential of targeting G protein-gated inwardly rectifying potassium (GIRK) channels in the central nervous system. Pharmacol Ther 2021; 223:107808. [PMID: 33476640 DOI: 10.1016/j.pharmthera.2021.107808] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
G protein-gated inwardly rectifying potassium channels (Kir3/GirK) are important for maintaining resting membrane potential, cell excitability and inhibitory neurotransmission. Coupled to numerous G protein-coupled receptors (GPCRs), they mediate the effects of many neurotransmitters, neuromodulators and hormones contributing to the general homeostasis and particular synaptic plasticity processes, learning, memory and pain signaling. A growing number of behavioral and genetic studies suggest a critical role for the appropriate functioning of the central nervous system, as well as their involvement in many neurologic and psychiatric conditions, such as neurodegenerative diseases, mood disorders, attention deficit hyperactivity disorder, schizophrenia, epilepsy, alcoholism and drug addiction. Hence, GirK channels emerge as a very promising tool to be targeted in the current scenario where these conditions already are or will become a global public health problem. This review examines recent findings on the physiology, function, dysfunction, and pharmacology of GirK channels in the central nervous system and highlights the relevance of GirK channels as a worthful potential target to improve therapies for related diseases.
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Okada M, Kozaki I, Honda H. Antidepressive effect of an inward rectifier K+ channel blocker peptide, tertiapin-RQ. PLoS One 2020; 15:e0233815. [PMID: 33186384 PMCID: PMC7665585 DOI: 10.1371/journal.pone.0233815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/13/2020] [Indexed: 11/18/2022] Open
Abstract
Renal outer medullary K+ channel, ROMK (Kir1.1, kcnj1) is expressed in the kidney and brain, but its role in the central nervous system remains unknown. Recent studies suggested an involvement of the ROMK channel in mental diseases. Tertiapin (TPN) is a European honey bee venom peptide and is reported to selectively block the ROMK channel. Here, we have chemically synthesized a series of mutated TPN peptides, including TPN-I8R and -M13Q (TPN-RQ), reported previously, and examined their blocking activity on the ROMK channel. Among 71 peptides tested, TPN-RQ was found to block the ROMK channel most effectively. Whole-cell patch-clamp recordings showed the essential roles of two disulfide bonds and the circular structure for the blockade activity. To examine the central role, we injected TPN-RQ intracerebroventricularly and examined the effects on depression- and anxiety-like behaviors in mice. TPN-RQ showed an antidepressive effect in tail-suspension and forced swim tests. The injection of TPN-RQ also enhanced the anxiety-like behavior in the elevated plus-maze and light/dark box tests and impaired spontaneous motor activities in balance beam and wheel running tests. Administration of TPM-RQ suppressed the anti-c-Fos immunoreactivity in the lateral septum, without affecting immunoreactivity in antidepressant-related nuclei, e.g. the dorsal raphe nucleus and locus coeruleus. TPN-RQ may exert its antidepressive effects through a different mechanism from current drugs.
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Affiliation(s)
- Masayoshi Okada
- Department of Medical Life Science, College of Life Science, Kurashiki University of Science and the Arts, Kurashiki, Okayama, Japan
- * E-mail:
| | - Ikkou Kozaki
- Department of Biomolecular Engineering, Graduate Schoosl of Engineering, Nagoya University, Nagoya, Japan
| | - Hiroyuki Honda
- Department of Biomolecular Engineering, Graduate Schoosl of Engineering, Nagoya University, Nagoya, Japan
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Korczak M, Kurowski P, Leśniak A, Grönbladh A, Filipowska A, Bujalska-Zadrożny M. GABA B receptor intracellular signaling: novel pathways for depressive disorder treatment? Eur J Pharmacol 2020; 885:173531. [PMID: 32871173 DOI: 10.1016/j.ejphar.2020.173531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/22/2022]
Abstract
Affecting over 320 million people around the world, depression has become a formidable challenge for modern medicine. In addition, an increasing number of studies cast doubt on the monoamine theory of depressive disorder and, worryingly, antidepressant medications only significantly benefit patients with severe depression. Thus, it is not surprising that researchers have shown an increased interest in new theories attempting to explain the pathogenesis of this disease. One example is the excitatory/inhibitory transmission imbalance theory. These abnormalities involve glutamate and γ-aminobutyric acid (GABA) signaling. Studies on GABAB receptors and their antagonists are particularly promising for the treatment of depressive disorders. In this paper, intracellular pathways controlled by GABAB receptors and their links to depression are described, including the impact of ketamine on GABAergic synaptic transmission.
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Affiliation(s)
- Maciej Korczak
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Warsaw, Poland
| | - Przemysław Kurowski
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Warsaw, Poland.
| | - Anna Leśniak
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Warsaw, Poland
| | - Alfhild Grönbladh
- The Beijer Laboratory, Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, The Uppsala University, Uppsala, Sweden
| | - Anna Filipowska
- Department of Biosensors and Processing of Biomedical Signals, The Silesian University of Technology, Zabrze, Poland
| | - Magdalena Bujalska-Zadrożny
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, The Medical University of Warsaw, Warsaw, Poland
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Serotonin hyperpolarizes the dorsal raphe nucleus neurons of mice by activating G protein–coupled inward rectifier potassium channels. Neuroreport 2020; 31:928-935. [DOI: 10.1097/wnr.0000000000001501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Patel D, Kuyucak S, Doupnik CA. Structural Determinants Mediating Tertiapin Block of Neuronal Kir3.2 Channels. Biochemistry 2020; 59:836-850. [PMID: 31990535 DOI: 10.1021/acs.biochem.9b01098] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Tertiapin (TPN) is a 21 amino acid venom peptide from Apis mellifera that inhibits certain members of the inward rectifier potassium (Kir) channel family at a nanomolar affinity with limited specificity. Structure-based computational simulations predict that TPN behaves as a pore blocker; however, the molecular determinants mediating block of neuronal Kir3 channels have been inconclusive and unvalidated. Here, using molecular docking and molecular dynamics (MD) simulations with 'potential of mean force' (PMF) calculations, we investigated the energetically most favored interaction of TPN with several Kir3.x channel structures. The resulting binding model for Kir3.2-TPN complexes was then tested by targeted mutagenesis of the predicted contact sites, and their impact on the functional channel block was measured electrophysiologically. Together, our findings indicate that a high-affinity TPN block of Kir3.2 channels involves a pore-inserting lysine side chain requiring (1) hydrophobic interactions at a phenylalanine ring surrounding the channel pore and (2) electrostatic interactions with two adjacent Kir3.2 turret regions. Together, these interactions collectively stabilize high-affinity toxin binding to the Kir3.2 outer vestibule, which orients the ε-amino group of TPN-K21 to occupy the outermost K+ binding site of the selectivity filter. The structural determinants for the TPN block described here also revealed a favored subunit arrangement for assembled Kir3.x heteromeric channels, in addition to a multimodal binding capacity of TPN variants consistent with the functional dyad model for polybasic peptide pore blockers. These novel findings will aid efforts in re-engineering the TPN pharmacophore to develop peptide variants having unique and distinct Kir channel blocking properties.
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Affiliation(s)
- Dharmeshkumar Patel
- School of Physics , University of Sydney , Sydney , New South Wales 2006 , Australia
| | - Serdar Kuyucak
- School of Physics , University of Sydney , Sydney , New South Wales 2006 , Australia
| | - Craig A Doupnik
- Department of Molecular Pharmacology & Physiology , University of South Florida College of Medicine , 12901 Bruce B. Downs Boulevard , Tampa , Florida 33612 , United States
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Albert PR, Vahid-Ansari F. The 5-HT1A receptor: Signaling to behavior. Biochimie 2019; 161:34-45. [DOI: 10.1016/j.biochi.2018.10.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/23/2018] [Indexed: 02/06/2023]
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Vo BN, Abney KK, Anderson A, Marron Fernandez de Velasco E, Benneyworth MA, Daniels JS, Morrison RD, Hopkins CR, Weaver CD, Wickman K. VU0810464, a non-urea G protein-gated inwardly rectifying K + (K ir 3/GIRK) channel activator, exhibits enhanced selectivity for neuronal K ir 3 channels and reduces stress-induced hyperthermia in mice. Br J Pharmacol 2019; 176:2238-2249. [PMID: 30924523 DOI: 10.1111/bph.14671] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/16/2019] [Accepted: 02/20/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE G protein-gated inwardly rectifying K+ (Kir 3) channels moderate the activity of excitable cells and have been implicated in neurological disorders and cardiac arrhythmias. Most neuronal Kir 3 channels consist of Kir 3.1 and Kir 3.2 subtypes, while cardiac Kir 3 channels consist of Kir 3.1 and Kir 3.4 subtypes. Previously, we identified a family of urea-containing Kir 3 channel activators, but these molecules exhibit suboptimal pharmacokinetic properties and modest selectivity for Kir 3.1/3.2 relative to Kir 3.1/3.4 channels. Here, we characterize a non-urea activator, VU0810464, which displays nanomolar potency as a Kir 3.1/3.2 activator, improved selectivity for neuronal Kir 3 channels, and improved brain penetration. EXPERIMENTAL APPROACH We used whole-cell electrophysiology to measure the efficacy and potency of VU0810464 in neurons and the selectivity of VU0810464 for neuronal and cardiac Kir 3 channel subtypes. We tested VU0810464 in vivo in stress-induced hyperthermia and elevated plus maze paradigms. Parallel studies with ML297, the prototypical activator of Kir 3.1-containing Kir 3 channels, were performed to permit direct comparisons. KEY RESULTS VU0810464 and ML297 exhibited comparable efficacy and potency as neuronal Kir 3 channel activators, but VU0810464 was more selective for neuronal Kir 3 channels. VU0810464, like ML297, reduced stress-induced hyperthermia in a Kir 3-dependent manner in mice. ML297, but not VU0810464, decreased anxiety-related behaviour as assessed with the elevated plus maze test. CONCLUSION AND IMPLICATIONS VU0810464 represents a new class of Kir 3 channel activator with enhanced selectivity for Kir 3.1/3.2 channels. VU0810464 may be useful for examining Kir 3.1/3.2 channel contributions to complex behaviours and for probing the potential of Kir 3 channel-dependent manipulations to treat neurological disorders.
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Affiliation(s)
- Baovi N Vo
- Department of Pharmacology, University of Minnesota, Minneapolis, MN
| | - Kristopher K Abney
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN
| | - Allison Anderson
- Department of Pharmacology, University of Minnesota, Minneapolis, MN
| | | | | | | | - Ryan D Morrison
- Research and Development, Precera Bioscience, Inc., Franklin, TN
| | - Corey R Hopkins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE
| | | | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN
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GIRK Channel Activity in Dopamine Neurons of the Ventral Tegmental Area Bidirectionally Regulates Behavioral Sensitivity to Cocaine. J Neurosci 2019; 39:3600-3610. [PMID: 30837265 DOI: 10.1523/jneurosci.3101-18.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/17/2019] [Accepted: 02/22/2019] [Indexed: 12/19/2022] Open
Abstract
Dopamine (DA) neurons of the VTA have been widely implicated in the cellular and behavioral responses to drugs of abuse. Inhibitory G protein signaling mediated by GABAB receptors (GABABRs) and D2 DA receptors (D2Rs) regulates the excitability of VTA DA neurons, DA neurotransmission, and behaviors modulated by DA. Most of the somatodendritic inhibitory effect of GABABR and D2R activation on DA neurons reflects the activation of G protein-gated inwardly rectifying K+ (GIRK) channels. Furthermore, GIRK-dependent signaling in VTA DA neurons can be weakened by exposure to psychostimulants and strengthened by phasic DA neuron firing. The objective of this study was to determine how the strength of GIRK channel activity in VTA DA neurons influences sensitivity to cocaine. We used a Cre-dependent viral strategy to overexpress the individual GIRK channel subunits in VTA DA neurons of male and female adult mice, leading to enhancement (GIRK2) or suppression (GIRK3) of GIRK channel activity. Overexpression of GIRK3 decreased somatodendritic GABABR- and D2R-dependent signaling and increased cocaine-induced locomotor activity, whereas overexpression of GIRK2 increased GABABR-dependent signaling and decreased cocaine-induced locomotion. Neither manipulation impacted anxiety- or depression-related behavior, despite the link between such behaviors and DA signaling. Together, these data show that behavioral sensitivity to cocaine in mice is inversely proportional to the strength of GIRK channel activity in VTA DA neurons and suggest that direct activators of the unique VTA DA neuron GIRK channel subtype (GIRK2/GIRK3 heteromer) could represent a promising therapeutic target for treatment of addiction.SIGNIFICANCE STATEMENT Inhibitory G protein signaling in dopamine (DA) neurons, including that mediated by G protein-gated inwardly rectifying K+ (GIRK) channels, has been implicated in behavioral sensitivity to cocaine. Here, we used a viral approach to bidirectionally manipulate GIRK channel activity in DA neurons of the VTA. We found that decreasing GIRK channel activity in VTA DA neurons increased behavioral sensitivity to cocaine, whereas increasing GIRK channel activity decreased behavioral sensitivity to cocaine. These manipulations did not alter anxiety- or depression-related behaviors. These data highlight the unique GIRK channel subtype in VTA DA neurons as a possible therapeutic target for addiction.
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14
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Llamosas N, Ugedo L, Torrecilla M. Inactivation of GIRK channels weakens the pre- and postsynaptic inhibitory activity in dorsal raphe neurons. Physiol Rep 2018; 5:5/3/e13141. [PMID: 28196855 PMCID: PMC5309581 DOI: 10.14814/phy2.13141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 12/26/2016] [Accepted: 01/06/2017] [Indexed: 01/17/2023] Open
Abstract
The serotonergic tone of the dorsal raphe (DR) is regulated by 5-HT1A receptors, which negatively control serotonergic activity via the activation of G protein-coupled inwardly rectifying K+ (GIRK) channels. In addition, DR activity is modulated by local GABAergic transmission, which is believed to play a key role in the development of mood-related disorders. Here, we sought to characterize the role of GIRK2 subunit-containing channels on the basal electrophysiological properties of DR neurons and to investigate whether the presynaptic and postsynaptic activities of 5-HT1A, GABAB, and GABAA receptors are affected by Girk2 gene deletion. Whole-cell patch-clamp recordings in brain slices from GIRK2 knockout mice revealed that the GIRK2 subunit contributes to maintenance of the resting membrane potential and to the membrane input resistance of DR neurons. 5-HT1A and GABAB receptor-mediated postsynaptic currents were almost absent in the mutant mice. Spontaneous and evoked GABAA receptor-mediated transmissions were markedly reduced in GIRK2 KO mice, as the frequency and amplitude of spontaneous IPSCs were reduced, the paired-pulse ratio was increased and GABA-induced whole-cell currents were decreased. Similarly, the pharmacological blockade of GIRK channels with tertiapin-Q prevented the 5-HT1A and GABAB receptor-mediated postsynaptic currents and increased the paired-pulse ratio. Finally, deletion of the Girk2 gene also limited the presynaptic inhibition of GABA release exerted by 5-HT1A and GABAB receptors. These results indicate that the properties and inhibitory activity of DR neurons are highly regulated by GIRK2 subunit-containing channels, introducing GIRK channels as potential candidates for studying the pathophysiology and treatment of affective disorders.
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Affiliation(s)
- Nerea Llamosas
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Luisa Ugedo
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Maria Torrecilla
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
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15
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Deletion of GIRK2 subunit containing GIRK channels of neurons expressing dopamine transporter decrease immobility time on forced swimming in mice. Neurosci Lett 2018; 665:140-146. [DOI: 10.1016/j.neulet.2017.11.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/06/2017] [Accepted: 11/10/2017] [Indexed: 12/29/2022]
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16
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Cannady R, Rinker JA, Nimitvilai S, Woodward JJ, Mulholland PJ. Chronic Alcohol, Intrinsic Excitability, and Potassium Channels: Neuroadaptations and Drinking Behavior. Handb Exp Pharmacol 2018; 248:311-343. [PMID: 29374839 DOI: 10.1007/164_2017_90] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Neural mechanisms underlying alcohol use disorder remain elusive, and this lack of understanding has slowed the development of efficacious treatment strategies for reducing relapse rates and prolonging abstinence. While synaptic adaptations produced by chronic alcohol exposure have been extensively characterized in a variety of brain regions, changes in intrinsic excitability of critical projection neurons are understudied. Accumulating evidence suggests that prolonged alcohol drinking and alcohol dependence produce plasticity of intrinsic excitability as measured by changes in evoked action potential firing and after-hyperpolarization amplitude. In this chapter, we describe functional changes in cell firing of projection neurons after long-term alcohol exposure that occur across species and in multiple brain regions. Adaptations in calcium-activated (KCa2), voltage-dependent (KV7), and G protein-coupled inwardly rectifying (Kir3 or GIRK) potassium channels that regulate the evoked firing and after-hyperpolarization parallel functional changes in intrinsic excitability induced by chronic alcohol. Moreover, there are strong genetic links between alcohol-related behaviors and genes encoding KCa2, KV7, and GIRK channels, and pharmacologically targeting these channels reduces alcohol consumption and alcohol-related behaviors. Together, these studies demonstrate that chronic alcohol drinking produces adaptations in KCa2, KV7, and GIRK channels leading to impaired regulation of the after-hyperpolarization and aberrant cell firing. Correcting the deficit in the after-hyperpolarization with positive modulators of KCa2 and KV7 channels and altering the GIRK channel binding pocket to block the access of alcohol represent a potentially highly effective pharmacological approach that can restore changes in intrinsic excitability and reduce alcohol consumption in affected individuals.
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Affiliation(s)
- Reginald Cannady
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - Jennifer A Rinker
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - Sudarat Nimitvilai
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - John J Woodward
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - Patrick J Mulholland
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA.
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17
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Zhao C, Su M, Wang Y, Li X, Zhang Y, Du X, Zhang H. Selective Modulation of K + Channel Kv7.4 Significantly Affects the Excitability of DRN 5-HT Neurons. Front Cell Neurosci 2017; 11:405. [PMID: 29311835 PMCID: PMC5735115 DOI: 10.3389/fncel.2017.00405] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 12/04/2017] [Indexed: 11/17/2022] Open
Abstract
The serotonin (5-HT) system originating in the dorsal raphe nucleus (DRN) is implicated in various mood- and emotion-related disorders, such as anxiety, fear and stress. Abnormal activity of DRN 5-HT neurons is the key factor in the development of these disorders. Here, we describe a crucial role for the Kv7.4 potassium channel in modulating DRN 5-HT neuronal excitability. We demonstrate that Kv7.4 is selectively expressed in 5-HT neurons of the DRN. Using selective Kv7.4 opener fasudil and Kv7.4 knock-out mice, we demonstrate that Kv7.4 is a potent modulator of DRN 5-HT neuronal excitability. Furthermore, we demonstrate that the cellular redox signaling mechanism is involved in this 5-HT activation of Kv7.4. The current study suggests a new strategy for treating psychiatric disorders related to altered activity of DRN 5-HT neurons using K+ channel modulators.
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Affiliation(s)
- Chen Zhao
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Min Su
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Yingzi Wang
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Xinmeng Li
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Yongxue Zhang
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Xiaona Du
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
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18
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Mlinar B, Montalbano A, Waider J, Lesch KP, Corradetti R. Increased functional coupling of 5-HT 1A autoreceptors to GIRK channels in Tph2 -/- mice. Eur Neuropsychopharmacol 2017; 27:1258-1267. [PMID: 29126768 DOI: 10.1016/j.euroneuro.2017.10.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 10/14/2017] [Accepted: 10/22/2017] [Indexed: 10/18/2022]
Abstract
Firing activity of serotonergic neurons is under regulatory control by somatodendritic 5-HT1A autoreceptors (5-HT1AARs). Enhanced 5-HT1AAR functioning may cause decreased serotonergic signaling in brain and has thereby been implicated in the etiology of mood and anxiety disorders. Tryptophan hydroxylase-2 knockout (Tph2-/-) mice exhibit sensitization of 5-HT1A agonist-induced inhibition of serotonergic neuron firing and thus represents a unique animal model of enhanced 5-HT1AAR functioning. To elucidate the mechanisms underlying 5-HT1AAR supersensitivity in Tph2-/- mice, we characterized the activation of G protein-coupled inwardly-rectifying potassium (GIRK) conductance by the 5-HT1A receptor agonist 5-carboxamidotryptamine using whole-cell recordings from serotonergic neurons in dorsal raphe nucleus. Tph2-/- mice exhibited a mean twofold leftward shift of the agonist concentration-response curve (p < 0.001) whereas the maximal response, proportional to the 5-HT1AAR number, was not different (p = 0.42) compared to Tph2+/- and Tph2+/+ littermates. No differences were found in the basal inwardly-rectifying potassium conductance, determined in the absence of agonist, (p = 0.80) nor in total GIRK conductance activated by intracellular application of GTP-γ-S (p = 0.69). These findings indicate increased functional coupling of 5-HT1AARs to GIRK channels in Tph2-/- mice without a concomitant increase in 5-HT1AARs and/or GIRK channel density. In addition, no changes were found in α1-adrenergic facilitation of firing (p = 0.72) indicating lack of adaptive changes Tph2-/- mice. 5-HT1AAR supersensitivity may represents a previously unrecognized cause of serotonergic system hypofunction and associated disorders and provides a possible explanation for conflicting results on the correlation between 5-HT1AAR density and depression in clinical imaging studies.
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Affiliation(s)
- Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy.
| | - Alberto Montalbano
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Jonas Waider
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany; Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
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19
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Borroto-Escuela DO, DuPont CM, Li X, Savelli D, Lattanzi D, Srivastava I, Narváez M, Di Palma M, Barbieri E, Andrade-Talavera Y, Cuppini R, Odagaki Y, Palkovits M, Ambrogini P, Lindskog M, Fuxe K. Disturbances in the FGFR1-5-HT1A Heteroreceptor Complexes in the Raphe-Hippocampal 5-HT System Develop in a Genetic Rat Model of Depression. Front Cell Neurosci 2017; 11:309. [PMID: 29066953 PMCID: PMC5641403 DOI: 10.3389/fncel.2017.00309] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/19/2017] [Indexed: 12/04/2022] Open
Abstract
The FGFR1-5-HT1A heteroreceptor complexes are involved in neuroplasticity in the rat hippocampus and in the mesencephalic raphe 5-HT nerve cells. There exists a 5-HT1A protomer enhancement of FGFR1 protomer signaling. Acute and 10 day treatment with intracerebroventricular (i.c.v.) FGF-2 and the 5-HT1A agonist 8-OH-DPAT produced enhanced antidepressant effects in the forced swim test (FST). We studied in the current work the disturbances in the FGFR1-5-HT1A heterocomplexes in a genetic rat model of depression, the Flinders sensitive line (FSL) rats of Sprague-Dawley (SD) origin, by means of neurochemical, neurophysiological and behavioral techniques. In control SD rats, the FGFR1 agonist SUN11602 and FGF2 produced a significant reduction of G protein-coupled inwardly rectifying K+ channel (GIRK) currents induced by 8-OH-DPAT in the CA1 area of the hippocampus. In FSL rats, only i.c.v. 8-OH-DPAT alone treatment produced a significant reduction in the immobility time. The combined i.c.v. treatment (FGF2 + 8-OH-DPAT) in FSL rats did not cause a significant decrease in immobility time in the FST. However, in the SD rats this combined treatment produced a significant reduction. Furthermore, in the FSL rat a significant increase in the density of FGFR1-5-HT1A proximity ligation assay (PLA) positive clusters was only found after i.c.v. 8-OH-DPAT treatment alone in the CA2 and CA3 areas. In the SD rat a significant increase in the density of specific PLA clusters was only observed in the CA2 area of the i.c.v. combined treatment (FGF2 + 8-OH-DPAT) group. No treatment led to significant changes in the PLA clusters of the dorsal raphe in the FSL rat. However, significant changes in the density of specific PLA clusters were only found in the dorsal raphe of SD rats after combined treatment and treatment with 8-OH-DPAT alone. The results indicate that in FSL rats compared with SD rats alterations may develop in the ability of 8-OH-DPAT and combined FGFR1 and 5-HT1A agonist treatment to increase the density of FGFR1-5-HT1A heteroreceptor complexes of the dorsal raphe. It is proposed that such deficits in FSL rats may possibly reflect a failure of the combined agonist treatment to uncouple the 5-HT1A autoreceptors from the GIRK channels. This may contribute to the failure of producing antidepressant-like effects in the FSL rat by combined agonist treatment as seen in the SD rat. The antidepressant-like effects seen with the 5-HT1A agonist alone treatment in FSL but not in SD rats may instead involve significant increases in the FGFR1-5-HT1A complexes of the CA2 and CA3 areas of the hippocampus.
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Affiliation(s)
- Dasiel O Borroto-Escuela
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Caitlin M DuPont
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Xiang Li
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - David Savelli
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Davide Lattanzi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Ipsit Srivastava
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Manuel Narváez
- Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - Michael Di Palma
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Elisa Barbieri
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Yuniesky Andrade-Talavera
- Neuronal Oscillations Laboratory, Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Yuji Odagaki
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Miklos Palkovits
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Patrizia Ambrogini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Maria Lindskog
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Kjell Fuxe
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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20
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Contestabile A, Magara S, Cancedda L. The GABAergic Hypothesis for Cognitive Disabilities in Down Syndrome. Front Cell Neurosci 2017; 11:54. [PMID: 28326014 PMCID: PMC5339239 DOI: 10.3389/fncel.2017.00054] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/14/2017] [Indexed: 12/04/2022] Open
Abstract
Down syndrome (DS) is a genetic disorder caused by the presence of a third copy of chromosome 21. DS affects multiple organs, but it invariably results in altered brain development and diverse degrees of intellectual disability. A large body of evidence has shown that synaptic deficits and memory impairment are largely determined by altered GABAergic signaling in trisomic mouse models of DS. These alterations arise during brain development while extending into adulthood, and include genesis of GABAergic neurons, variation of the inhibitory drive and modifications in the control of neural-network excitability. Accordingly, different pharmacological interventions targeting GABAergic signaling have proven promising preclinical approaches to rescue cognitive impairment in DS mouse models. In this review, we will discuss recent data regarding the complex scenario of GABAergic dysfunctions in the trisomic brain of DS mice and patients, and we will evaluate the state of current clinical research targeting GABAergic signaling in individuals with DS.
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Affiliation(s)
- Andrea Contestabile
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT) Genova, Italy
| | - Salvatore Magara
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT) Genova, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT)Genova, Italy; Dulbecco Telethon InstituteGenova, Italy
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21
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Luckhart C, Philippe TJ, Le François B, Vahid-Ansari F, Geddes SD, Béïque JC, Lagace DC, Daigle M, Albert PR. Sex-dependent adaptive changes in serotonin-1A autoreceptor function and anxiety in Deaf1-deficient mice. Mol Brain 2016; 9:77. [PMID: 27488351 PMCID: PMC4973060 DOI: 10.1186/s13041-016-0254-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/23/2016] [Indexed: 12/20/2022] Open
Abstract
The C (-1019) G rs6295 promoter polymorphism of the serotonin-1A (5-HT1A) receptor gene is associated with major depression in several but not all studies, suggesting that compensatory mechanisms mediate resilience. The rs6295 risk allele prevents binding of the repressor Deaf1 increasing 5-HT1A receptor gene transcription, and the Deaf1-/- mouse model shows an increase in 5-HT1A autoreceptor expression. In this study, Deaf1-/- mice bred on a mixed C57BL6-BALB/c background were compared to wild-type littermates for 5-HT1A autoreceptor function and behavior in males and females. Despite a sustained increase in 5-HT1A autoreceptor binding levels, the amplitude of the 5-HT1A autoreceptor-mediated current in 5-HT neurons was unaltered in Deaf1-/- mice, suggesting compensatory changes in receptor function. Consistent with increased 5-HT1A autoreceptor function in vivo, hypothermia induced by the 5-HT1A agonist DPAT was augmented in early generation male but not female Deaf1-/- mice, but was reduced with succeeding generations. Loss of Deaf1 resulted in a mild anxiety phenotype that was sex-and test-dependent, with no change in depression-like behavior. Male Deaf1 knockout mice displayed anxiety-like behavior in the open field and light-dark tests, while female Deaf1-/- mice showed increased anxiety only in the elevated plus maze. These data show that altered 5-HT1A autoreceptor regulation in male Deaf1-/- mice can be compensated for by generational adaptation of receptor response that may help to normalize behavior. The sex dependence of Deaf1 function in mice is consistent with a greater role for 5-HT1A autoreceptors in sensitivity to depression in men.
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Affiliation(s)
- Christine Luckhart
- Ottawa Hospital Research Institute (Neuroscience), Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Tristan J Philippe
- Ottawa Hospital Research Institute (Neuroscience), Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Brice Le François
- Ottawa Hospital Research Institute (Neuroscience), Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Faranak Vahid-Ansari
- Ottawa Hospital Research Institute (Neuroscience), Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Sean D Geddes
- Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Jean-Claude Béïque
- Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Diane C Lagace
- Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada
| | - Mireille Daigle
- Ottawa Hospital Research Institute (Neuroscience), Ottawa, Canada
| | - Paul R Albert
- Ottawa Hospital Research Institute (Neuroscience), Ottawa, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H-8M5, Canada.
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23
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Lecca S, Pelosi A, Tchenio A, Moutkine I, Lujan R, Hervé D, Mameli M. Rescue of GABAB and GIRK function in the lateral habenula by protein phosphatase 2A inhibition ameliorates depression-like phenotypes in mice. Nat Med 2016; 22:254-61. [PMID: 26808347 DOI: 10.1038/nm.4037] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023]
Abstract
The lateral habenula (LHb) encodes aversive signals, and its aberrant activity contributes to depression-like symptoms. However, a limited understanding of the cellular mechanisms underlying LHb hyperactivity has precluded the development of pharmacological strategies to ameliorate depression-like phenotypes. Here we report that an aversive experience in mice, such as foot-shock exposure (FsE), induces LHb neuronal hyperactivity and depression-like symptoms. This occurs along with increased protein phosphatase 2A (PP2A) activity, a known regulator of GABAB receptor (GABABR) and G protein-gated inwardly rectifying potassium (GIRK) channel surface expression. Accordingly, FsE triggers GABAB1 and GIRK2 internalization, leading to rapid and persistent weakening of GABAB-activated GIRK-mediated (GABAB-GIRK) currents. Pharmacological inhibition of PP2A restores both GABAB-GIRK function and neuronal excitability. As a consequence, PP2A inhibition ameliorates depression-like symptoms after FsE and in a learned-helplessness model of depression. Thus, GABAB-GIRK plasticity in the LHb represents a cellular substrate for aversive experience. Furthermore, its reversal by PP2A inhibition may provide a novel therapeutic approach to alleviate symptoms of depression in disorders that are characterized by LHb hyperactivity.
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Affiliation(s)
- Salvatore Lecca
- Institut du Fer à Moulin, Paris, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) S839, Paris, France.,Université Pierre et Marie Curie, Paris, France
| | - Assunta Pelosi
- Institut du Fer à Moulin, Paris, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) S839, Paris, France.,Université Pierre et Marie Curie, Paris, France
| | - Anna Tchenio
- Institut du Fer à Moulin, Paris, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) S839, Paris, France.,Université Pierre et Marie Curie, Paris, France
| | - Imane Moutkine
- Institut du Fer à Moulin, Paris, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) S839, Paris, France.,Université Pierre et Marie Curie, Paris, France
| | - Rafael Lujan
- Instituto de Investigación en Discapacidades Neurológicas, Albacete, Spain.,Universidad Castilla-La Mancha, Facultad de Medicina, Departamento de Ciencias Médicas, Campus Biosanitario, Albacete, Spain
| | - Denis Hervé
- Institut du Fer à Moulin, Paris, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) S839, Paris, France.,Université Pierre et Marie Curie, Paris, France
| | - Manuel Mameli
- Institut du Fer à Moulin, Paris, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) S839, Paris, France.,Université Pierre et Marie Curie, Paris, France
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24
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Montalbano A, Corradetti R, Mlinar B. Pharmacological Characterization of 5-HT1A Autoreceptor-Coupled GIRK Channels in Rat Dorsal Raphe 5-HT Neurons. PLoS One 2015; 10:e0140369. [PMID: 26460748 PMCID: PMC4603796 DOI: 10.1371/journal.pone.0140369] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/24/2015] [Indexed: 01/19/2023] Open
Abstract
G protein-activated inwardly rectifying potassium (GIRK) channels in 5-HT neurons are assumed to be principal effectors of 5-hydroxytryptamine 1A (5-HT1A) autoreceptors, but their pharmacology, subunit composition and the role in regulation of 5-HT neuron activity have not been fully elucidated. We sought for a pharmacological tool for assessing the functional role of GIRK channels in 5-HT neurons by characterizing the effects of drugs known to block GIRK channels in the submicromolar range of concentrations. Whole-cell voltage-clamp recording in brainstem slices were used to determine concentration-response relationships for the selected GIRK channel blockers on 5-HT1A autoreceptor-activated inwardly rectifying K+ conductance in rat dorsal raphe 5-HT neurons. 5-HT1A autoreceptor-activated GIRK conductance was completely blocked by the nonselective inwardly rectifying potassium channels blocker Ba2+ (EC50 = 9.4 μM, full block with 100 μM) and by SCH23390 (EC50 = 1.95 μM, full block with 30 μM). GIRK-specific blocker tertiapin-Q blocked 5-HT1A autoreceptor-activated GIRK conductance with high potency (EC50 = 33.6 nM), but incompletely, i.e. ~16% of total conductance resulted to be tertiapin-Q-resistant. U73343 and SCH28080, reported to block GIRK channels with submicromolar EC50s, were essentially ineffective in 5-HT neurons. Our data show that inwardly rectifying K+ channels coupled to 5-HT1A autoreceptors display pharmacological properties generally expected for neuronal GIRK channels, but different from GIRK1-GIRK2 heteromers, the predominant form of brain GIRK channels. Distinct pharmacological properties of GIRK channels in 5-HT neurons should be explored for the development of new therapeutic agents for mood disorders.
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Affiliation(s)
- Alberto Montalbano
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
- * E-mail:
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Mayfield J, Blednov YA, Harris RA. Behavioral and Genetic Evidence for GIRK Channels in the CNS: Role in Physiology, Pathophysiology, and Drug Addiction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 123:279-313. [PMID: 26422988 DOI: 10.1016/bs.irn.2015.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G protein-coupled inwardly rectifying potassium (GIRK) channels are widely expressed throughout the brain and mediate the inhibitory effects of many neurotransmitters. As a result, these channels are important for normal CNS function and have also been implicated in Down syndrome, Parkinson's disease, psychiatric disorders, epilepsy, and drug addiction. Knockout mouse models have provided extensive insight into the significance of GIRK channels under these conditions. This review examines the behavioral and genetic evidence from animal models and genetic association studies in humans linking GIRK channels with CNS disorders. We further explore the possibility that subunit-selective modulators and other advanced research tools will be instrumental in establishing the role of individual GIRK subunits in drug addiction and other relevant CNS diseases and in potentially advancing treatment options for these disorders.
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Affiliation(s)
- Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA.
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
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Dascal N, Kahanovitch U. The Roles of Gβγ and Gα in Gating and Regulation of GIRK Channels. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 123:27-85. [DOI: 10.1016/bs.irn.2015.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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