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Alemi M, Pereira AR, Cerqueira-Nunes M, Monteiro C, Galhardo V, Cardoso-Cruz H. Role of Glutamatergic Projections from Lateral Habenula to Ventral Tegmental Area in Inflammatory Pain-Related Spatial Working Memory Deficits. Biomedicines 2023; 11:biomedicines11030820. [PMID: 36979799 PMCID: PMC10045719 DOI: 10.3390/biomedicines11030820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/02/2023] [Accepted: 03/04/2023] [Indexed: 03/30/2023] Open
Abstract
The lateral habenula (LHb) and the ventral tegmental area (VTA), which form interconnected circuits, have important roles in the crucial control of sensory and cognitive motifs. Signaling in the LHb-VTA pathway can be exacerbated during pain conditions by a hyperactivity of LHb glutamatergic neurons to inhibit local VTA DAergic cells. However, it is still unclear whether and how this circuit is endogenously engaged in pain-related cognitive dysfunctions. To answer this question, we modulated this pathway by expressing halorhodopsin in LHb neurons of adult male rats, and then selectively inhibited the axonal projections from these neurons to the VTA during a working memory (WM) task. Behavioral performance was assessed after the onset of an inflammatory pain model. We evaluated the impact of the inflammatory pain in the VTA synapses by performing immunohistochemical characterization of specific markers for GABAergic (GAD65/67) and dopaminergic neurons (dopamine transporter (DAT), dopamine D2 receptor (D2r) and tyrosine hydroxylase (TH)). Our results revealed that inhibition of LHb terminals in the VTA during the WM delay-period elicits a partial recovery of the performance of pain animals (in higher complexity challenges); this performance was not accompanied by a reduction of nociceptive responses. Finally, we found evidence that the pain-affected animals exhibit VTA structural changes, namely with an upregulation of GAD65/67, and a downregulation of DAT and D2r. These results demonstrate a role of LHb neurons and highlight their responsibility in the stability of the local VTA network, which regulates signaling in frontal areas necessary to support WM processes.
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Affiliation(s)
- Mobina Alemi
- Instituto de Investigação e Inovação em Saúde-Pain Neurobiology Group, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Faculdade de Medicina, Departamento de Biomedicina-Unidade de Biologia Experimental, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
| | - Ana Raquel Pereira
- Instituto de Investigação e Inovação em Saúde-Pain Neurobiology Group, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Faculdade de Medicina, Departamento de Biomedicina-Unidade de Biologia Experimental, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
| | - Mariana Cerqueira-Nunes
- Instituto de Investigação e Inovação em Saúde-Pain Neurobiology Group, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Faculdade de Medicina, Departamento de Biomedicina-Unidade de Biologia Experimental, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
- Programa Doutoral em Neurociências, Faculdade de Medicina, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
| | - Clara Monteiro
- Instituto de Investigação e Inovação em Saúde-Pain Neurobiology Group, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Faculdade de Medicina, Departamento de Biomedicina-Unidade de Biologia Experimental, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
| | - Vasco Galhardo
- Instituto de Investigação e Inovação em Saúde-Pain Neurobiology Group, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Faculdade de Medicina, Departamento de Biomedicina-Unidade de Biologia Experimental, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
| | - Helder Cardoso-Cruz
- Instituto de Investigação e Inovação em Saúde-Pain Neurobiology Group, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal
- Faculdade de Medicina, Departamento de Biomedicina-Unidade de Biologia Experimental, Universidade do Porto, Rua Doutor Plácido da Costa, 4200-450 Porto, Portugal
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Chronic infusions of mecamylamine into the medial habenula: Effects on nicotine self-administration in rats. Behav Brain Res 2022; 416:113574. [PMID: 34499942 PMCID: PMC8492541 DOI: 10.1016/j.bbr.2021.113574] [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: 06/07/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 01/09/2023]
Abstract
The habenula is an epithalamic structure through which descending connections go from the telencephalon to the brainstem, putting it in a key location to provide feedback control over the ascending projections from the brainstem to the telencephalon. The medial habenula has a high concentration of nicotinic receptors. We assessed the role of medial habenular nicotinic receptors for nicotine self-administration (SA) in female young adult Sprague-Dawley rats. The rats had bilateral chronic infusion cannulae placed into the medial habenula nucleus. Each cannula was connected to a slow delivery osmotic minipump to chronically infuse mecamylamine (100 µg/side/day) or vehicle for four consecutive weeks. The rats were tested for nicotine SA for the first two weeks of mecamylamine infusion. Then, they had one week of enforced abstinence, during which they had no access to the nicotine SA. Finally, they had one week of resumed nicotine SA access. There was a significantly differential mecamylamine effects in animals with lower and higher pretreatment baseline nicotine SA. Rats with lower baseline nicotine SA levels showed a nearly significant mecamylamine-induced reduction in SA while those with higher baseline levels of SA showed a significant mecamylamine-induced increase in nicotine SA. This study determined that medial habenular nicotinic receptors are important for nicotine reinforcement. Baseline level of performance makes a crucial difference for the involvement of habenular mechanisms in nicotine reinforcement with nicotinic activation being important for maintaining nicotine self-administration for those with lower levels of baseline self-administration and the opposite effect with subjects with higher levels of baseline self-administration.
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Hu H, Cui Y, Yang Y. Circuits and functions of the lateral habenula in health and in disease. Nat Rev Neurosci 2020; 21:277-295. [PMID: 32269316 DOI: 10.1038/s41583-020-0292-4] [Citation(s) in RCA: 233] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2020] [Indexed: 12/14/2022]
Abstract
The past decade has witnessed exponentially growing interest in the lateral habenula (LHb) owing to new discoveries relating to its critical role in regulating negatively motivated behaviour and its implication in major depression. The LHb, sometimes referred to as the brain's 'antireward centre', receives inputs from diverse limbic forebrain and basal ganglia structures, and targets essentially all midbrain neuromodulatory systems, including the noradrenergic, serotonergic and dopaminergic systems. Its unique anatomical position enables the LHb to act as a hub that integrates value-based, sensory and experience-dependent information to regulate various motivational, cognitive and motor processes. Dysfunction of the LHb may contribute to the pathophysiology of several psychiatric disorders, especially major depression. Recently, exciting progress has been made in identifying the molecular and cellular mechanisms in the LHb that underlie negative emotional state in animal models of drug withdrawal and major depression. A future challenge is to translate these advances into effective clinical treatments.
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Affiliation(s)
- Hailan Hu
- Department of Psychiatry of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. .,The MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Brain Science and Brain Medicine, Hangzhou, China. .,NHC and CAMS Key Laboratory of Medical Neurobiology, Mental Health Center, Zhejiang University, Hangzhou, China. .,Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China. .,Fountain-Valley Institute for Life Sciences, Guangzhou, China.
| | - Yihui Cui
- The MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Brain Science and Brain Medicine, Hangzhou, China
| | - Yan Yang
- The MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Brain Science and Brain Medicine, Hangzhou, China
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Mathis V, Barbelivien A, Majchrzak M, Mathis C, Cassel JC, Lecourtier L. The Lateral Habenula as a Relay of Cortical Information to Process Working Memory. Cereb Cortex 2018; 27:5485-5495. [PMID: 28334072 DOI: 10.1093/cercor/bhw316] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/19/2016] [Indexed: 11/14/2022] Open
Abstract
Working memory is a cognitive ability allowing the temporary storage of information to solve problems or adjust behavior. While working memory is known to mainly depend on the medial prefrontal cortex (mPFC), very few is known about how cortical information are relayed subcortically. By its connectivity, the lateral habenula (lHb) might act as a subcortical relay for cortical information. Indeed, the lHb receives inputs from several mPFC subregions, and recent findings suggest a role for the lHb in online processing of spatial information, a fundamental aspect of working memory. In rats, in a delayed non-matching to position paradigm, using focal microinjections of the GABAA agonist muscimol we showed that inactivation of the lHb (16 ng in 0.2 µL per side), as well as disconnection between the prelimbic region of the mPFC (mPFC/PrL, 32 ng in 0.4 µL in one hemisphere) and the lHb (16 ng in 0.2 µL in the lHb in the contralateral hemisphere) impaired working memory. The deficits were unlikely to result from motivational or motor deficits as muscimol did not affect reward collection or cue responding latencies, and did not increase the number of omissions. These results show for the first time the implication of the lHb in mPFC-dependent memory processes, likely as a relay of mPFC/PrL information. They also open new perspectives in the understanding of the top-down processing of high-level cognitive functions.
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Affiliation(s)
- Victor Mathis
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, F-67000 Strasbourg, France.,LNCA, UMR 7364, CNRS, F-67000 Strasbourg, France
| | - Alexandra Barbelivien
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, F-67000 Strasbourg, France.,LNCA, UMR 7364, CNRS, F-67000 Strasbourg, France
| | - Monique Majchrzak
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, F-67000 Strasbourg, France.,LNCA, UMR 7364, CNRS, F-67000 Strasbourg, France
| | - Chantal Mathis
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, F-67000 Strasbourg, France.,LNCA, UMR 7364, CNRS, F-67000 Strasbourg, France
| | - Jean-Christophe Cassel
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, F-67000 Strasbourg, France.,LNCA, UMR 7364, CNRS, F-67000 Strasbourg, France
| | - Lucas Lecourtier
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, F-67000 Strasbourg, France.,LNCA, UMR 7364, CNRS, F-67000 Strasbourg, France
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The Lateral Habenula and Adaptive Behaviors. Trends Neurosci 2017; 40:481-493. [DOI: 10.1016/j.tins.2017.06.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/04/2017] [Accepted: 06/06/2017] [Indexed: 02/05/2023]
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Role of the lateral habenula in memory through online processing of information. Pharmacol Biochem Behav 2017; 162:69-78. [PMID: 28709783 DOI: 10.1016/j.pbb.2017.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/04/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022]
Abstract
Our memory abilities, whether they involve short-term working memory or long-term episodic or procedural memories, are essential for our well-being, our capacity to adapt to constraints of our environment and survival. Therefore, several key brain regions and neurotransmitter systems are engaged in the processing of sensory information to either maintain such information in working memory so that it will quickly be used, and/or participate in the elaboration and storage of enduring traces useful for longer periods of time. Animal research has recently attracted attention on the lateral habenula which, as shown in rodents and non-human primates, seems to process information stemming in the main regions involved in memory processing, e.g., the medial prefrontal cortex, the hippocampus, the amygdala, the septal region, the basal ganglia, and participates in the control of key memory-related neurotransmitters systems, i.e., dopamine, serotonin, acetylcholine. Recently, the lateral habenula has been involved in working and spatial reference memories, in rodents, likely by participating in online processing of contextual information. In addition, several behavioral studies strongly suggest that it is also involved in the processing of the emotional valance of incoming information in order to adapt to particularly stressful situations. Therefore, the lateral habenula appears like a key region at the interface between cognition and emotion to participate in the selection of appropriate behaviors.
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Schmidt CE, Manbeck KE, Shelley D, Harris AC. Blockade of cholinergic transmission elicits somatic signs in nicotine-naïve adolescent rats. Front Pharmacol 2015; 6:239. [PMID: 26539119 PMCID: PMC4611158 DOI: 10.3389/fphar.2015.00239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 10/05/2015] [Indexed: 01/24/2023] Open
Abstract
High doses of the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine can elicit somatic signs resembling those associated with nicotine withdrawal in nicotine-naïve adult rats. Understanding this phenomenon, and its possible modulation by acute nicotine and age, could inform the use of mecamylamine as both an experimental tool and potential pharmacotherapy for tobacco dependence and other disorders. This study evaluated the ability of high-dose mecamylamine to elicit somatic signs in adolescent rats, and the potential for acute nicotine pretreatment to potentiate this effect as previously reported in adults. Single or repeated injections of mecamylamine (1.5 or 3.0 mg/kg, s.c.) elicited somatic signs in nicotine-naïve adolescents, but this effect was not influenced by 2 h pretreatment with acute nicotine (0.5 mg/kg, s.c.). In an initial evaluation of the effects of age in this model, mecamylamine (2.25 mg/kg, s.c.) elicited somatic signs in nicotine-naïve adolescents and adults. This effect was modestly enhanced following acute nicotine injections in adults but not in adolescents, even when a higher nicotine dose (1.0 rather than 0.5 mg/kg, s.c.) was used in adolescents to account for age differences in nicotine pharmacokinetics. These studies are the first to show that mecamylamine elicits somatic signs in nicotine-naïve adolescent rats, an effect that should be considered when designing and interpreting studies examining effects of high doses of mecamylamine in adolescents. Our findings also provide preliminary evidence that these signs may be differentially modulated by acute nicotine pretreatment in adolescents versus adults.
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Affiliation(s)
- Clare E Schmidt
- Minneapolis Medical Research Foundation , Minneapolis, MN, USA ; Department of Neuroscience, University of Minnesota , Minneapolis, MN, USA
| | - Katherine E Manbeck
- Minneapolis Medical Research Foundation , Minneapolis, MN, USA ; Department of Psychology, University of Minnesota , Minneapolis, MN, USA
| | - David Shelley
- Minneapolis Medical Research Foundation , Minneapolis, MN, USA
| | - Andrew C Harris
- Minneapolis Medical Research Foundation , Minneapolis, MN, USA ; Department of Psychology, University of Minnesota , Minneapolis, MN, USA ; Department of Medicine, University of Minnesota , Minneapolis, MN, USA
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Shin SS, Dixon CE. Targeting α7 nicotinic acetylcholine receptors: a future potential for neuroprotection from traumatic brain injury. Neural Regen Res 2015; 10:1552-4. [PMID: 26692836 PMCID: PMC4660732 DOI: 10.4103/1673-5374.165309] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 12/13/2022] Open
Affiliation(s)
- Samuel S. Shin
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - C. Edward Dixon
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Role of nicotinic receptors in the lateral habenula in the attenuation of amphetamine-induced prepulse inhibition deficits of the acoustic startle response in rats. Psychopharmacology (Berl) 2015; 232:3009-17. [PMID: 25912180 PMCID: PMC4515155 DOI: 10.1007/s00213-015-3940-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/12/2015] [Indexed: 11/27/2022]
Abstract
RATIONALE Prepulse inhibition (PPI) refers to the reduction of the startle response magnitude when a startling stimulus is closely preceded by a weak stimulus. PPI is commonly used to measure sensorimotor gating. In rats, the PPI reduction induced by the dopamine agonist apomorphine can be reversed by systemic administration of nicotine. A high concentration of nicotinic receptors is found in the lateral habenula (LHb), an epithalamic structure with efferent projections to brain regions involved in the modulation of PPI, which has been shown to regulate the activity of midbrain dopamine neurons. OBJECTIVES The prospective role of nicotinic receptors in the LHb in the regulation of PPI was assessed in this study, using different pharmacological models of sensorimotor gating deficits. METHODS Interactions between systemic amphetamine and haloperidol and intra-LHb infusions of mecamylamine (10 μg/side) or nicotine (30 μg/side) on PPI were analyzed in Experiments 1 and 2. Intra-LHb infusions of different nicotine doses (25, and 50 μg/side) and their interactions with systemic administration of amphetamine or dizocilpine on PPI were examined in Experiments 3 and 4. RESULTS Infusions of nicotine into the LHb dose-dependently attenuated amphetamine-induced PPI deficits but had no effect on PPI disruptions caused by dizocilpine. Intra-LHb mecamylamine infusions did not affect PPI nor interact with dopaminergic manipulations. CONCLUSIONS These results are congruent with previous reports of systemic nicotine effects on PPI, suggesting a role of the LHb in the attenuation of sensorimotor gating deficits caused by the hyperactivity of dopamine systems.
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Levin ED, Hall BJ, Rezvani AH. Heterogeneity across brain regions and neurotransmitter interactions with nicotinic effects on memory function. Curr Top Behav Neurosci 2015; 23:87-101. [PMID: 25655888 DOI: 10.1007/978-3-319-13665-3_4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nicotinic acetylcholine receptors have been shown in many studies to be critically involved in memory function. The precise roles these receptors play depend on the receptor subtype, their anatomic localization, their interactions with other parts of the neural systems underlying cognition and the particular domain of cognitive function. Nicotinic agonists can significantly improve learning, memory, and attention. Nicotinic receptors in the hippocampus are innervated by cholinergic projections from the medial septum and diagonal band. Local infusions of either α7 or α4β2 nicotinic antagonists into either the dorsal or ventral hippocampus produce amnestic effects in rats navigating about a radial arm maze. There is cholinergic innervation of nicotinic receptors in other components of the limbic system as well. In the basolateral amygdala and the anterior thalamus, similar amnestic effects of nicotinic α7 and α4β2 antagonists are seen. Interestingly, there are no additive amnestic effects observed in these limbic areas when α7 and α4β2 receptor antagonists are combined. The particular expression patterns of α7 and α4β2 nicotinic receptors in these limbic and cortical areas may explain this nonadditivity, but further research is needed to determine the specific cause of this phenomenon. Nicotinic receptor mechanisms in the limbic system play an important role in cognitive impairment for a variety of neurological disorders, including Alzheimer's disease and schizophrenia. Alzheimer's disease results in a dramatic decrease in hippocampal nicotinic receptor density, affecting α4β2 receptor expression most prominently. In schizophrenia, there are anomalies in α7 nicotinic receptor expression, which seem to be crucial for the cognitive impairment of the disorder. Chronic nicotine exposure, such as seen with tobacco use, results in an increase in nicotinic receptor density in the limbic system. This effect appears to be related to the desensitization of nicotinic receptors seen after agonist application. Open questions remain concerning the role of desensitization versus activation of nicotinic receptors in cognitive improvement.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box #104790, Durham, NC, 27710, USA,
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A comparison of mecamylamine and bupropion effects on memory-related responses induced by nicotine and scopolamine in the novel object recognition test in mice. Pharmacol Rep 2014; 66:638-46. [DOI: 10.1016/j.pharep.2014.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 02/03/2014] [Indexed: 11/24/2022]
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Sakhi K, Belle MDC, Gossan N, Delagrange P, Piggins HD. Daily variation in the electrophysiological activity of mouse medial habenula neurones. J Physiol 2013; 592:587-603. [PMID: 24247982 PMCID: PMC3934703 DOI: 10.1113/jphysiol.2013.263319] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
AbstractIntrinsic daily or circadian rhythms arise through the outputs of the master circadian clock in the brain's suprachiasmatic nuclei (SCN) as well as circadian oscillators in other brain sites and peripheral tissues. SCN neurones contain an intracellular molecular clock that drives these neurones to exhibit pronounced day–night differences in their electrical properties. The epithalamic medial habenula (MHb) expresses clock genes, but little is known about the bioelectric properties of mouse MHb neurones and their potential circadian characteristics. Therefore, in this study we used a brain slice preparation containing the MHb to determine the basic electrical properties of mouse MHb neurones with whole-cell patch clamp electrophysiology, and investigated whether these vary across the day–night cycle. MHb neurones (n = 230) showed heterogeneity in electrophysiological state, ranging from highly depolarised cells (∼ −25 to −30 mV) that are silent with no membrane activity or display depolarised low-amplitude membrane oscillations, to neurones that were moderately hyperpolarised (∼40 mV) and spontaneously discharging action potentials. These electrical states were largely intrinsically regulated and were influenced by the activation of small-conductance calcium-activated potassium channels. When considered as one population, MHb neurones showed significant circadian variation in their spontaneous firing rate and resting membrane potential. However, in recordings of MHb neurones from mice lacking the core molecular circadian clock, these temporal differences in MHb activity were absent, indicating that circadian clock signals actively regulate the timing of MHb neuronal states. These observations add to the extracellularly recorded rhythms seen in other brain areas and establish that circadian mechanisms can influence the membrane properties of neurones in extra-SCN sites. Collectively, the results of this study indicate that the MHb may function as an intrinsic secondary circadian oscillator in the brain, which can shape daily information flow in key brain processes, such as reward and addiction.
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Affiliation(s)
- Kanwal Sakhi
- AV Hill 2.016, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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Levin ED. Complex relationships of nicotinic receptor actions and cognitive functions. Biochem Pharmacol 2013; 86:1145-52. [PMID: 23928190 DOI: 10.1016/j.bcp.2013.07.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 07/23/2013] [Accepted: 07/23/2013] [Indexed: 10/26/2022]
Abstract
Nicotine has been shown in a variety of studies to improve cognitive function including learning, memory and attention. Nicotine both stimulates and desensitizes nicotinic receptors, thus acting both as an agonist and a net antagonist. The relative roles of these two actions for nicotine-induced cognitive improvement have not yet been fully determined. We and others have found that acute nicotinic antagonist treatment can improve learning and attention. Nicotine acts on a variety of nicotinic receptor subtypes. The relative role and interactions of neuronal nicotinic receptor subtypes for cognition also needs to be better characterized. Nicotine acts on nicotinic receptors in a wide variety of brain areas. The role of some of these areas such as the hippocampus has been relatively well studied but other areas like the thalamus, which has the densest nicotinic receptor concentration are still only partially characterized. In a series of studies we characterized nicotinic receptor actions, anatomic localization and circuit interactions, which are critical to nicotine effects on the cognitive functions of learning, memory and attention. The relative role of increases and decreases in nicotinic receptor activation by nicotine were determined in regionally specific studies of the hippocampus, the amygdala, the frontal cortex and the mediodorsal thalamic nucleus with local infusions of antagonists of nicotinic receptor subtypes (α7 and α4β2). The understanding of the functional neural bases of cognitive function is fundamental to the more effective development of nicotinic drugs for treating cognitive dysfunction.
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Affiliation(s)
- Edward D Levin
- Duke University Medical Center, Department of Psychiatry and Behavioral Sciences, Box 104790 DUMC, Durham, NC 27710, USA.
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Darcq E, Koebel P, Del Boca C, Pannetier S, Kirstetter AS, Garnier JM, Hanauer A, Befort K, Kieffer BL. RSK2 signaling in brain habenula contributes to place aversion learning. Learn Mem 2011; 18:574-8. [PMID: 21852432 DOI: 10.1101/lm.2221011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
RSK2 is a Ser/Thr kinase acting in the Ras/MAPK pathway. Rsk2 gene deficiency leads to the Coffin-Lowry Syndrome, notably characterized by cognitive deficits. We found that mrsk2 knockout mice are unable to associate an aversive stimulus with context in a lithium-induced conditioned place aversion task requiring both high-order cognition and emotional processing. Virally mediated shRNA-RSK2 knockdown in the habenula, whose involvement in cognition is receiving increasing attention, also ablated contextual conditioning. RSK2 signaling in the habenula, therefore, is essential for this task. Our study reveals a novel role for RSK2 in cognitive processes and uncovers the critical implication of an intriguing brain structure in place aversion learning.
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Affiliation(s)
- Emmanuel Darcq
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université de Strasbourg, 67404 Illkirch, France
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The habenula: from stress evasion to value-based decision-making. Nat Rev Neurosci 2011; 11:503-13. [PMID: 20559337 DOI: 10.1038/nrn2866] [Citation(s) in RCA: 663] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Surviving in a world with hidden rewards and dangers requires choosing the appropriate behaviours. Recent discoveries indicate that the habenula plays a prominent part in such behavioural choice through its effects on neuromodulator systems, in particular the dopamine and serotonin systems. By inhibiting dopamine-releasing neurons, habenula activation leads to the suppression of motor behaviour when an animal fails to obtain a reward or anticipates an aversive outcome. Moreover, the habenula is involved in behavioural responses to pain, stress, anxiety, sleep and reward, and its dysfunction is associated with depression, schizophrenia and drug-induced psychosis. As a highly conserved structure in the brain, the habenula provides a fundamental mechanism for both survival and decision-making.
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