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Kolesnikova TO, Demin KA, Costa FV, de Abreu MS, Kalueff AV. Zebrafish models for studying cognitive enhancers. Neurosci Biobehav Rev 2024; 164:105797. [PMID: 38971515 DOI: 10.1016/j.neubiorev.2024.105797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/16/2024] [Accepted: 07/03/2024] [Indexed: 07/08/2024]
Abstract
Cognitive decline is commonly seen both in normal aging and in neurodegenerative and neuropsychiatric diseases. Various experimental animal models represent a valuable tool to study brain cognitive processes and their deficits. Equally important is the search for novel drugs to treat cognitive deficits and improve cognitions. Complementing rodent and clinical findings, studies utilizing zebrafish (Danio rerio) are rapidly gaining popularity in translational cognitive research and neuroactive drug screening. Here, we discuss the value of zebrafish models and assays for screening nootropic (cognitive enhancer) drugs and the discovery of novel nootropics. We also discuss the existing challenges, and outline future directions of research in this field.
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Affiliation(s)
| | - Konstantin A Demin
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia
| | - Fabiano V Costa
- Neurobiology Program, Sirius University of Science and Technology, Sochi, Russia
| | - Murilo S de Abreu
- Graduate Program in Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil; West Caspian University, Baku, Azerbaijan.
| | - Allan V Kalueff
- Neurobiology Program, Sirius University of Science and Technology, Sochi, Russia; Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia; Suzhou Key Laboratory on Neurobiology and Cell Signaling, Department of Biological Sciences, School of Science, Xi'an Jiaotong-Liverpool University, Suzhou, China.
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Wang X, Wang Q, Song M, Wang Y, Shen X, Sun Y, Guo C, Geng P, Ma C, Jin X. Chronic but not acute nicotine treatment ameliorates acute inflammation-induced working memory impairment by increasing CRTC1 and HCN2 in adult male mice. CNS Neurosci Ther 2024; 30:e14627. [PMID: 38353058 PMCID: PMC10865150 DOI: 10.1111/cns.14627] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Systemic inflammation in which lipopolysaccharide (LPS) is released into circulation can cause cognitive dysfunction and we have previously shown that LPS impaired working memory (WM) which refers to the ability to guide incoming behavior by retrieving recently acquired information. However, the mechanism is not very clear, and currently, there is no approved strategy to improve inflammation-induced WM deficit. Notably, epidemiological studies have demonstrated a lower occurrence rate of inflammatory-related diseases in smoking patients, suggesting that inflammation-induced WM impairment may be improved by nicotine treatment. Here, our object is to investigate the effect and potential mechanisms of acute and chronic nicotine treatment on LPS-produced WM deficiency. METHODS Delayed alternation T-maze task (DAT) was applied for evaluating WM which includes both the short-term information storage and the ability to correct errors in adult male mice. Immunofluorescence staining and immunoblotting were used for assessing the levels and distribution of CREB-regulated transcription coactivator 1 (CRTC1) and hyperpolarization-activated cation channels 2 (HCN2) in the medial prefrontal cortex (mPFC) and hippocampus. Quantitative PCR and ELISA were employed for analyzing the mRNA and protein levels of TNF-α and IL-1β. RESULTS Our results revealed that administration of LPS (i.p.) at a dose of 0.5 mg/kg significantly produced WM impairment in the DAT task accompanied by an increase in IL-1β and TNF-α expression in the mPFC. Moreover, intra-mPFC infusion of IL-1Ra, an IL-1 antagonist, markedly alleviated LPS-induced WM deficiency. More important, chronic (2 weeks) but not acute nicotine (0.2 mg/kg, subcutaneous) treatment significantly alleviated LPS-induced WM deficiency by upregulating CRTC1 and HCN2. Of note, intra-mPFC infusion of HCN blocker ZD7288 produced significant WM deficiency. CONCLUSIONS In summary, in this study, we show that chronic nicotine treatment ameliorates acute inflammation-induced working memory deficiency by increasing CRTC1 and HCN2 in adult male mice.
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Affiliation(s)
- Xiaona Wang
- School of Life ScienceNanchang UniversityNanchangChina
- Institute of Biomedical Innovation, Jiangxi Medical CollegeNanchang UniversityNanchangChina
| | - Qian Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchCapital Medical UniversityBeijingChina
| | - Min Song
- Institute of NeuroscienceThe Second The Second Affiliated Hospital of Soochow UniversitySuzhouChina
| | - Yihui Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchCapital Medical UniversityBeijingChina
| | - Xianzhi Shen
- Institute of NeuroscienceThe Second The Second Affiliated Hospital of Soochow UniversitySuzhouChina
| | - Yanyun Sun
- Institute of NeuroscienceThe Second The Second Affiliated Hospital of Soochow UniversitySuzhouChina
| | - Chun Guo
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Panpan Geng
- Department of Histology and Embryology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchCapital Medical UniversityBeijingChina
| | - Chaolin Ma
- School of Life ScienceNanchang UniversityNanchangChina
- Institute of Biomedical Innovation, Jiangxi Medical CollegeNanchang UniversityNanchangChina
| | - Xinchun Jin
- Department of Histology and Embryology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchCapital Medical UniversityBeijingChina
- Institute of NeuroscienceThe Second The Second Affiliated Hospital of Soochow UniversitySuzhouChina
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Pastor V, Dalto JF, Medina JH. α7 nicotinic acetylcholine receptors in the medial prefrontal cortex control rewarding but not aversive memory expression in a dopamine-sensitive manner. Pharmacol Biochem Behav 2023; 227-228:173594. [PMID: 37385456 DOI: 10.1016/j.pbb.2023.173594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Emotional learning involves the association between sensory cues and rewarding or aversive stimuli, and this stored information can be recalled during memory retrieval. In this process, the medial prefrontal cortex (mPFC) plays an essential role. We have previously shown that the antagonism of α7 nicotinic acetylcholine receptors (nAChRs) by methyllycaconitine (MLA) in the mPFC blocked cue-induced cocaine memory retrieval. However, little is known about the involvement of prefrontal α7 nAChRs in the retrieval of aversive memories. Here, by using pharmacology and different behavioral tasks, we found that MLA did not affect aversive memory retrieval, indicating a differential effect of cholinergic prefrontal control of appetitive and aversive memories. Despite being shown that acetylcholine modulates dopamine release in the mPFC, it remains unknown if those modulatory systems act together to control reward-based behavior. We examined that question and found that dopamine type 1 receptor (D1R) activation prevented MLA-induced blockade of cocaine CPP retrieval. Our results suggest that α7 nAChRs and D1R signaling interact in the mPFC to modulate cocaine-associated memory retrieval.
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Affiliation(s)
- Verónica Pastor
- CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis" (IBCN), Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Medicina, Departamento de Ciencias Fisiológicas, Buenos Aires, Argentina.
| | - Juliana F Dalto
- CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis" (IBCN), Buenos Aires, Argentina
| | - Jorge H Medina
- CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis" (IBCN), Buenos Aires, Argentina; Instituto Tecnológico de Buenos Aires (ITBA), Buenos Aires, Argentina
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Cao K, Xiang J, Dong YT, Xu Y, Guan ZZ. Activation of α7 Nicotinic Acetylcholine Receptor by its Selective Agonist Improved Learning and Memory of Amyloid Precursor Protein/Presenilin 1 (APP/PS1) Mice via the Nrf2/HO-1 Pathway. Med Sci Monit 2022; 28:e933978. [PMID: 34980874 PMCID: PMC8742434 DOI: 10.12659/msm.933978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/24/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND To reveal the mechanism underlying the effect of alpha7 nicotinic acetylcholine receptor (nAChR) on neurodegeneration in Alzheimer disease (AD), the influence of the receptor on recognition in APP/PS1 mice was evaluated by using its selective agonist (PNU-282987). MATERIAL AND METHODS APP/PS1 and wild-type (WT) mice were treated with PNU or saline, respectively, for 7 days at the ages of 6 and 10 months. RESULTS Morris water maze analysis showed that both at 6 and 10 months of age, PNU treatment enhanced the learning and memory of APP/PS1 mice. However, PNU treatment did not alter the number of senile plaques. Furthermore, a higher protein expression of Nrf2/HO-1, ADAM10, SYP, and SNAP-25, and a lower level of oxidative stress, were observed in the hippocampus of APP/PS1 mice treated with PNU compared with the control group. CONCLUSIONS The results indicated that the activation of alpha7 nAChR by PNU improved the learning and memory of mice carrying the APP/PS1 mutation, regulated the levels of enzymes that mediate APP metabolization to reduce ß-amyloid peptide damage, and decreased the level of oxidative stress and maintained synaptic plasticity, in which the mechanism might be enhancement of the Nrf2/HO-1 pathway.
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Affiliation(s)
- Kun Cao
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, PR China
- Department of Hepatobiliary Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, PR China
| | - Jie Xiang
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, PR China
- Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University) of the Ministry of Education, Guiyang, Guizhou, PR China
| | - Yang-Ting Dong
- Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University) of the Ministry of Education, Guiyang, Guizhou, PR China
- Provincial Key Laboratory of Medical Molecular Biology, Guiyang, Guizhou, PR China
| | - Yi Xu
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, PR China
- Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University) of the Ministry of Education, Guiyang, Guizhou, PR China
| | - Zhi-Zhong Guan
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, PR China
- Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University) of the Ministry of Education, Guiyang, Guizhou, PR China
- Provincial Key Laboratory of Medical Molecular Biology, Guiyang, Guizhou, PR China
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Abstract
Nicotinic acetylcholine receptors (nAChRs) play a critical role in the neuropharmacology of learning and memory. As such, naturally occurring alkaloids that regulate nAChR activity have gained interest for understanding and potentially improving memory function. In this study, we tested the acute effects of three known nicotinic alkaloids, nicotine, cotinine, and anatabine, in suppressing scopolamine-induced memory deficit in rodents by using two classic memory paradigms, Y-maze and novel object recognition (NOR) in mice and rats, respectively. We found that all compounds were able to suppress scopolamine-induced spatial memory deficit in the Y-maze spontaneous alternation paradigm. However, only nicotine was able to suppress the short-term object memory deficit in NOR, despite the higher doses of cotinine and anatabine used to account for their potential differences in nAChR activity. These results indicate that cotinine and anatabine can uniquely regulate short-term spatial memory, while nicotine seems to have more robust and general role in memory regulation in rodents. Thus, nAChR-activating alkaloids may possess distinct procognitive properties in rodents, depending on the memory types examined.
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Prefrontal cortex nicotinic receptor inhibition by methyllycaconitine impaired cocaine-associated memory acquisition and retrieval. Behav Brain Res 2021; 406:113212. [PMID: 33657437 DOI: 10.1016/j.bbr.2021.113212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022]
Abstract
Cocaine administration has been shown to induce plastic changes in the medial prefrontal cortex (mPFC), which could represent a mechanism by which cocaine facilitates the association between cocaine rewarding effects with contextual cues. Nicotinic acetylcholine receptors (nAChRs) in the mPFC have critical roles in cognitive function including attention and memory and are key players in plasticity processes. However, whether nAChRs in the mPFC are required for the acquisition and maintenance of cocaine-associated memories is still unknown. To assess this question, we used the conditioning place preference (CPP) model to study the effect of intra-mPFC infusion of methyllycaconitine, a selective antagonist of α7 nAChRs, on the acquisition, consolidation and expression of cocaine-associated memory in adult rats. Our findings reveal that mPFC α7 nAChRs activation is necessary for the acquisition and retrieval, but not consolidation, of cocaine induced CPP. Moreover, cocaine-induced sensitization during CPP conditioning sessions was abolished by methyllycaconitine infusion in the mPFC. Together, these results identify mPFC α7 nAChRs as critical players involved in both acquiring and retrieving cocaine-associated memories. Considering that drug seeking often depends on the association between drug-paired cues and the rewarding effects of the drug, α7 nAChRs in the mPFC could be considered as potential targets for the prevention or treatment of cocaine use disorder.
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Sizer SE, Parrish BC, McCool BA. Chronic Ethanol Exposure Potentiates Cholinergic Neurotransmission in the Basolateral Amygdala. Neuroscience 2020; 455:165-176. [PMID: 33385490 DOI: 10.1016/j.neuroscience.2020.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 01/10/2023]
Abstract
Chronic intermittent ethanol (CIE) exposure dysregulates glutamatergic and GABAergic neurotransmission, facilitating basolateral amygdala (BLA) pyramidal neuron hyperexcitability and the expression of anxiety during withdrawal. It is unknown whether ethanol-induced alterations in nucleus basalis magnocellularis (NBM) cholinergic projections to the BLA mediate anxiety-related behaviors through direct modulation of GABA and glutamate afferents. Following 10 days of CIE exposure and 24 h of withdrawal, we recorded GABAergic and glutamatergic synaptic responses in BLA pyramidal neurons with electrophysiology, assessed total protein expression of cholinergic markers, and quantified acetylcholine and choline concentrations using a colorimetric assay. We measured α7 nicotinic acetylcholine receptor (nAChR) dependent modulation of presynaptic function at distinct inputs in AIR- and CIE-exposed BLA coronal slices as a functional read-out of cholinergic neurotransmission. CIE/withdrawal upregulates the endogenous activity of α7 nAChRs, facilitating release at both GABAergic' local' interneuron and glutamatergic synaptic responses to stria terminalis (ST) stimulation, with no effect at GABAergic lateral paracapsular cells (LPCs). CIE caused a three-fold increase in BLA acetylcholine concentration, with no changes in α7 nAChR or cholinergic marker expression. These data illustrate that α7 nAChR-dependent changes in presynaptic function serve as a proxy for CIE-dependent alterations in synaptic acetylcholine levels. Thus, cholinergic projections appear to mediate CIE-induced alterations at GABA/glutamate inputs.
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Affiliation(s)
- Sarah E Sizer
- Department of Physiology and Pharmacology, Piedmont Triad Community Research Center (PTCRC), Wake Forest School of Medicine, 115 S Chestnut Street, Winston-Salem, NC 27101, USA.
| | - Brian C Parrish
- Department of Physiology and Pharmacology, Piedmont Triad Community Research Center (PTCRC), Wake Forest School of Medicine, 115 S Chestnut Street, Winston-Salem, NC 27101, USA.
| | - Brian A McCool
- Department of Physiology and Pharmacology, Piedmont Triad Community Research Center (PTCRC), Wake Forest School of Medicine, 115 S Chestnut Street, Winston-Salem, NC 27101, USA.
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Dopamine D1 and muscarinic acetylcholine receptors in dorsal striatum are required for high speed running. Neurosci Res 2019; 156:50-57. [PMID: 31812651 DOI: 10.1016/j.neures.2019.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/07/2019] [Accepted: 11/28/2019] [Indexed: 12/15/2022]
Abstract
Dopamine (DA) signaling in the basal ganglia plays important roles in motor control. Motor deficiencies were previously reported in dopamine receptor D1 (D1R) and D2 (D2R) knockout mice. While these results indicate the involvement of DA receptors in motor execution, the null knockout (KO) mouse lacks the specificity necessary to determine when and where in the brain D1R and D2R function in motor execution. To address these questions, we restricted the loss of function temporally and spatially by using D1R conditional knockdown (cKD) mice and mice injected with antagonists against DA receptors directly into the dorsal striatum. In addition, we address the DA and acetylcholine (ACh) balance hypothesis by using antagonists against ACh receptors. We tested the motor ability of the mice with a newly devised task named the accelerating step-wheel. In this task, the maximum running speed was measured in a situation where the wheel rotation speed was gradually accelerated in one trial. We found significant decreases in the maximum running speed of D1R cKD mice and the mice injected with the antagonist against D1R or muscarinic ACh receptor. These results indicated that D1R and muscarinic ACh receptor in the dorsal striatum play pivotal roles in the execution of walking/running.
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α7 Nicotinic receptor-modulating agents reverse the hyperdopaminergic tone in the MAM model of schizophrenia. Neuropsychopharmacology 2018; 43:1712-1720. [PMID: 29695783 PMCID: PMC6006162 DOI: 10.1038/s41386-018-0066-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/02/2018] [Indexed: 01/05/2023]
Abstract
Recent evidence has emerged supporting a role for the cholinergic system in schizophrenia, including the potential of α7 modulators as a treatment strategy. However, preclinical studies to date have relied on studies in normal systems rather than on a validated developmental model of schizophrenia. Furthermore, there have been only few studies on whether orthosteric and allosteric modulators have differential impacts in such models. Thus, we investigated the effects of α7 agonists and positive allosteric modulators (PAMs) on dopamine (DA) neuron activity in the ventral tegmental area (VTA) in the methylazoxymethanol acetate (MAM) developmental disruption model of schizophrenia. Four different drugs were evaluated: PNU282987 (full agonist), SSR180711 (partial agonist) NS1738 (PAM type I) and PNU120596 (PAM type II). PNU120596 increased the number of spontaneously active VTA DA neurons in normal rats. In contrast, PNU282987 and SSR180711 reduced the hyperdopaminergic tone in MAM rats. This appeared to be due to effects on DA afferent regulation, in that PNU282987 or SSR180711 infusion into the ventral hippocampus of MAM rats replicated the decrease in the number of spontaneously active VTA DA neurons. In contrast, infusion of the same drugs into the basolateral amygdala increased the number of spontaneously active VTA DA neurons in normal rats without impacting MAM rats. These data suggest that α7 receptors may represent a promising target in the development of new pharmacological therapies for schizophrenia.
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Li DJ, Liu J, Hua X, Fu H, Huang F, Fei YB, Lu WJ, Shen FM, Wang P. Nicotinic acetylcholine receptor α7 subunit improves energy homeostasis and inhibits inflammation in nonalcoholic fatty liver disease. Metabolism 2018; 79:52-63. [PMID: 29129819 DOI: 10.1016/j.metabol.2017.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 10/31/2017] [Accepted: 11/04/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide; yet, the pathogenesis of the disorder is not completely understood. The nicotinic acetylcholine receptor α7 subunit (α7nAChR) plays an indispensable role in the vagus nerve-regulated cholinergic anti-inflammatory pathway. METHODS In the present study, we investigated the key role of α7nAChR in NAFLD development. Male wild-type (WT) and α7nAChR knockout (α7nAChR-/-) mice were fed a normal chow or a high-fat diet (HFD) for 16weeks to induce NAFLD. RESULTS We found that both the mRNA and protein levels of α7nAChR in the liver tissue of NAFLD mice were significantly higher than those in mice fed normal chow. There were no differences in food intake, body weight, hepatic cholesterol and triglyceride contents, and insulin sensitivity between WT and α7nAChR-/- mice under normal condition. When the WT and α7nAChR-/- mice were challenged with HFD, the body weight of α7nAChR-/- mice became higher than that of WT mice. The oxygen consumption and energy expenditure in HFD-fed α7nAChR-/- mice were significantly lower than that in HFD-fed WT mice. The HFD-fed α7nAChR-/- mice also showed more aggravated hepatic lipid accumulation, steatosis and oxidative stress than HFD-fed WT mice. Macrophage infiltration; mRNA levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β; and liver fibrosis were significantly accelerated in HFD-fed α7nAChR-/- mice compared to that in HFD-fed WT mice. In addition, the bolus insulin injection-activated insulin signaling pathway, which was reflected by the phosphorylation of insulin receptor at Tyr1162/Tyr1163 site (p-IRTyr1162/Tyr1163), insulin receptor substrate-1 at Tyr612 site (p-IRS-1Tyr612) and Akt at Ser473 (p-AktSer473), was significantly compromised in liver tissues of HFD-fed α7nAChR-/- mice relative to HFD-fed WT mice. Finally, pharmacologically activation of α7nAChR in HFD-fed mice, with a selective agonist PNU-282987, remarkably ameliorated the hepatic steatosis, inflammatory cell infiltration and fibrosis. CONCLUSION In conclusion, our results demonstrate that activation of α7nAChR improves energy homeostasis and inhibits inflammation in nonalcoholic fatty liver disease.
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Affiliation(s)
- Dong-Jie Li
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China
| | - Jian Liu
- Department of Biliary Tract Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Xia Hua
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Hui Fu
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China
| | - Fang Huang
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China
| | - Yi-Bo Fei
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China
| | - Wen-Jie Lu
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China
| | - Fu-Ming Shen
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China.
| | - Pei Wang
- Department of Pharmacology, School of Medicine, Tongji University, Shanghai, China; Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai, China.
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Roberts W, McKee SA. Effects of varenicline on cognitive performance in heavy drinkers: Dose-response effects and associations with drinking outcomes. Exp Clin Psychopharmacol 2018; 26:49-57. [PMID: 29389170 PMCID: PMC5797996 DOI: 10.1037/pha0000161] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Varenicline reduces drinking in people with alcohol use disorder, but little is known about the mechanisms underlying this effect. Varenicline targets α4β2 and α7 nicotinic acetylcholine receptors, which are associated with several cognitive functions such as working memory. Varenicline may improve drinking outcomes by enhancing cognitive functioning. The current manuscript reports on cognitive outcomes from a placebo-controlled, double-blind human laboratory experiment examining the effects of varenicline on drinking behavior (Verplaetse et al., 2016a). Participants were 55 adult heavy drinkers who met criteria for an alcohol use disorder. They were randomized to receive varenicline (1 mg/day, 2 mg/day) or placebo. They completed a baseline assessment of cognitive functioning (i.e., digits backward task, continuous performance task) before starting medication. After a medication titration period, they attended a laboratory session (post medication Day 8) where they completed the cognitive assessment battery and an alcohol-primed ad libitum drinking task. Blood was collected to measure plasma varenicline levels. Varenicline produced dose-dependent improvements in working memory. Although there was no significant effect of oral varenicline dose on response time on the continuous performance task, participants with higher levels of plasma varenicline showed greater improvement of reaction time (RT). Among participants receiving 2 mg/day varenicline, larger improvements in working memory were associated less drinking, although mediation analyses did not find a significant indirect effect. These findings suggest that varenicline can improve working memory above baseline levels in heavy drinkers. Varenicline may reduce rates of alcohol use by improving working memory. (PsycINFO Database Record
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Affiliation(s)
- Walter Roberts
- Yale School of Medicine, Department of Psychiatry, New Haven CT
- Corresponding author: Telephone: (203) 737-3529, Fax: (203) 737-4243, address: 2 Church St. South, Suite 109, Yale University School of Medicine, New Haven, CT 06519, , ORCID ID: 0000-0001-6817-884X
| | - Sherry A. McKee
- Yale School of Medicine, Department of Psychiatry, New Haven CT
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Maurer SV, Williams CL. The Cholinergic System Modulates Memory and Hippocampal Plasticity via Its Interactions with Non-Neuronal Cells. Front Immunol 2017; 8:1489. [PMID: 29167670 PMCID: PMC5682336 DOI: 10.3389/fimmu.2017.01489] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/23/2017] [Indexed: 01/12/2023] Open
Abstract
Degeneration of central cholinergic neurons impairs memory, and enhancement of cholinergic synapses improves cognitive processes. Cholinergic signaling is also anti-inflammatory, and neuroinflammation is increasingly linked to adverse memory, especially in Alzheimer's disease. Much of the evidence surrounding cholinergic impacts on the neuroimmune system focuses on the α7 nicotinic acetylcholine (ACh) receptor, as stimulation of this receptor prevents many of the effects of immune activation. Microglia and astrocytes both express this receptor, so it is possible that some cholinergic effects may be via these non-neuronal cells. Though the presence of microglia is required for memory, overactivated microglia due to an immune challenge overproduce inflammatory cytokines, which is adverse for memory. Blocking these exaggerated effects, specifically by decreasing the release of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6), has been shown to prevent inflammation-induced memory impairment. While there is considerable evidence that cholinergic signaling improves memory, fewer studies have linked the "cholinergic anti-inflammatory pathway" to memory processes. This review will summarize the current understanding of the cholinergic anti-inflammatory pathway as it relates to memory and will argue that one mechanism by which the cholinergic system modulates hippocampal memory processes is its influence on neuroimmune function via the α7 nicotinic ACh receptor.
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Affiliation(s)
- Sara V. Maurer
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
| | - Christina L. Williams
- Department of Psychology and Neuroscience, Duke University, Durham, NC, United States
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Potasiewicz A, Nikiforuk A, Hołuj M, Popik P. Stimulation of nicotinic acetylcholine alpha7 receptors rescue schizophrenia-like cognitive impairments in rats. J Psychopharmacol 2017; 31:260-271. [PMID: 28168926 DOI: 10.1177/0269881116675509] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Alpha7 nicotinic acetylcholine receptor (α7 nAChR) dysfunction plays an important role in schizophrenia. Positive allosteric modulators of α7 nAChR have emerged as a promising therapeutic approach to manage cognitive deficits that are inadequately treated in schizophrenic patients. The aim of the present study was to evaluate the ability of type I (CCMI) and type II (PNU120596) α7 nAChR positive allosteric modulators to counteract MK-801-induced cognitive and sensorimotor gating deficits. The activity of these compounds was compared with the action of the α7 nAChR agonist A582941. CCMI, PNU120596 and A582941 reversed the sensorimotor gating impairment evoked by MK-801 based on the prepulse inhibition of the startle response. Additionally, no MK-801-evoked working memory deficits were observed with α7 nAChR ligand pretreatment as assessed in a discrete paired-trial delayed alternation task. However, these compounds did not affect the rats' attentional performances in the five-choice serial reaction time test. The α7 nAChR agents demonstrated a beneficial effect on sensorimotor gating and some aspects of cognition tested in a rat model of schizophrenia. Therefore, these results support the use of α7 nAChR positive allosteric modulators as a potential treatment strategy in schizophrenia.
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Affiliation(s)
- Agnieszka Potasiewicz
- 1 Department of Behavioural Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Agnieszka Nikiforuk
- 1 Department of Behavioural Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Małgorzata Hołuj
- 1 Department of Behavioural Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Piotr Popik
- 1 Department of Behavioural Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland.,2 Faculty of Health Sciences, Jagiellonian University Medical College, Krakow, Poland
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Vicens P, Heredia L, Torrente M, Domingo JL. Behavioural effects of PNU-282987 and stress in an animal model of Alzheimer's disease. Psychogeriatrics 2017; 17:33-42. [PMID: 26817787 DOI: 10.1111/psyg.12189] [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: 10/19/2015] [Revised: 12/11/2015] [Accepted: 12/17/2015] [Indexed: 12/21/2022]
Abstract
BACKGROUND Cholinergic deficits play an important role in both cognitive and behavioural alterations in Alzheimer's disease. This study was aimed at evaluating the possible therapeutic role of PNU-282987 (PNU), an α7 nicotinic cholinergic receptor agonist, and the possible effects of stress in precipitating the onset of behavioural deficits in animals with susceptibility to Alzheimer's disease. METHODS B6C3-Tg mice with susceptibility to Alzheimer's disease and wild-type mice either with or without restraint stress received 0- or 1-mg/kg PNU. At 12 months old, mice were evaluated for activity levels, anxiety-like levels, and spatial learning and memory. RESULTS Data did not show the effects of PNU on activity and anxiety-like behaviour. No effect of PNU on acquisition of a spatial learning task was detected, but a reversal of stress effects on retention in the Morris water maze was observed in transgenic mice. CONCLUSIONS Further studies are needed in order to better understand the role of α7 nicotinic cholinergic receptor agonists in motor activity, anxiety, and spatial learning and memory and to develop more accurate pharmacological treatment of psychopathological diseases.
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Affiliation(s)
- Paloma Vicens
- Department of Psychology, Universitat Rovira i Virgili, Tarragona, Spain.,Research Center in Behavioral Assessment (CRAMC), Universitat Rovira i Virgili, Tarragona, Spain.,Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
| | - Luis Heredia
- Department of Psychology, Universitat Rovira i Virgili, Tarragona, Spain.,Research Center in Behavioral Assessment (CRAMC), Universitat Rovira i Virgili, Tarragona, Spain.,Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
| | - Margarita Torrente
- Department of Psychology, Universitat Rovira i Virgili, Tarragona, Spain.,Research Center in Behavioral Assessment (CRAMC), Universitat Rovira i Virgili, Tarragona, Spain.,Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
| | - José L Domingo
- Laboratory of Toxicology and Environmental Health, School of Medicine, Institut d'Investigació Sanitària Pere Virgili (IISPV), Universitat Rovira i Virgili, Tarragona, Spain
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Parikh V, Kutlu MG, Gould TJ. nAChR dysfunction as a common substrate for schizophrenia and comorbid nicotine addiction: Current trends and perspectives. Schizophr Res 2016; 171:1-15. [PMID: 26803692 PMCID: PMC4762752 DOI: 10.1016/j.schres.2016.01.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/07/2016] [Accepted: 01/10/2016] [Indexed: 11/18/2022]
Abstract
INTRODUCTION The prevalence of tobacco use in the population with schizophrenia is enormously high. Moreover, nicotine dependence is found to be associated with symptom severity and poor outcome in patients with schizophrenia. The neurobiological mechanisms that explain schizophrenia-nicotine dependence comorbidity are not known. This study systematically reviews the evidence highlighting the contribution of nicotinic acetylcholine receptors (nAChRs) to nicotine abuse in schizophrenia. METHODS Electronic data bases (Medline, Google Scholar, and Web of Science) were searched using the selected key words that match the aims set forth for this review. A total of 276 articles were used for the qualitative synthesis of this review. RESULTS Substantial evidence from preclinical and clinical studies indicated that dysregulation of α7 and β2-subunit containing nAChRs account for the cognitive and affective symptoms of schizophrenia and nicotine use may represent a strategy to remediate these symptoms. Additionally, recent meta-analyses proposed that early tobacco use may itself increase the risk of developing schizophrenia. Genetic studies demonstrating that nAChR dysfunction that may act as a shared vulnerability factor for comorbid tobacco dependence and schizophrenia were found to support this view. The development of nAChR modulators was considered an effective therapeutic strategy to ameliorate psychiatric symptoms and to promote smoking cessation in schizophrenia patients. CONCLUSIONS The relationship between schizophrenia and smoking is complex. While the debate for the self-medication versus addiction vulnerability hypothesis continues, it is widely accepted that a dysfunction in the central nAChRs represent a common substrate for various symptoms of schizophrenia and comorbid nicotine dependence.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19112, United States.
| | - Munir Gunes Kutlu
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19112, United States
| | - Thomas J Gould
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19112, United States
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McLean SL, Grayson B, Marsh S, Zarroug SHO, Harte MK, Neill JC. Nicotinic α7 and α4β2 agonists enhance the formation and retrieval of recognition memory: Potential mechanisms for cognitive performance enhancement in neurological and psychiatric disorders. Behav Brain Res 2015; 302:73-80. [PMID: 26327238 DOI: 10.1016/j.bbr.2015.08.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/25/2015] [Accepted: 08/27/2015] [Indexed: 12/11/2022]
Abstract
Cholinergic dysfunction has been shown to be central to the pathophysiology of Alzheimer's disease and has also been postulated to contribute to cognitive dysfunction observed in various psychiatric disorders, including schizophrenia. Deficits are found across a number of cognitive domains and in spite of several attempts to develop new therapies, these remain an unmet clinical need. In the current study we investigated the efficacy of donepezil, risperidone and selective nicotinic α7 and α4β2 receptor agonists to reverse a delay-induced deficit in recognition memory. Adult female Hooded Lister rats received drug treatments and were tested in the novel object recognition (NOR) task following a 6h inter-trial interval (ITI). In all treatment groups, there was no preference for the left or right identical objects in the acquisition trial. Risperidone failed to enhance recognition memory in this paradigm whereas donepezil was effective such that rats discriminated between the novel and familiar object in the retention trial following a 6h ITI. Although a narrow dose range of PNU-282987 and RJR-2403 was tested, only one dose of each increased recognition memory, the highest dose of PNU-282987 (10mg/kg) and the lowest dose of RJR-2403 (0.1mg/kg), indicative of enhanced cognitive performance. Interestingly, these compounds were also efficacious when administered either before the acquisition or the retention trial of the task, suggesting an important role for nicotinic receptor subtypes in the formation and retrieval of recognition memory.
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Affiliation(s)
- Samantha L McLean
- Bradford School of Pharmacy, University of Bradford, Richmond Road, BD7 1DP, UK
| | - Ben Grayson
- Manchester Pharmacy School, University of Manchester, Oxford Rd, M13 9PT, UK.
| | - Samuel Marsh
- Manchester Pharmacy School, University of Manchester, Oxford Rd, M13 9PT, UK
| | - Samah H O Zarroug
- Institute for Life Sciences, University of Southampton, University Road, SO17 1BJ, UK
| | - Michael K Harte
- Manchester Pharmacy School, University of Manchester, Oxford Rd, M13 9PT, UK
| | - Jo C Neill
- Manchester Pharmacy School, University of Manchester, Oxford Rd, M13 9PT, UK
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de Kloet SF, Mansvelder HD, De Vries TJ. Cholinergic modulation of dopamine pathways through nicotinic acetylcholine receptors. Biochem Pharmacol 2015. [PMID: 26208783 DOI: 10.1016/j.bcp.2015.07.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Nicotine addiction is highly prevalent in current society and is often comorbid with other diseases. In the central nervous system, nicotine acts as an agonist for nicotinic acetylcholine receptors (nAChRs) and its effects depend on location and receptor composition. Although nicotinic receptors are found in most brain regions, many studies on addiction have focused on the mesolimbic system and its reported behavioral correlates such as reward processing and reinforcement learning. Profound modulatory cholinergic input from the pedunculopontine and laterodorsal tegmentum to dopaminergic midbrain nuclei as well as local cholinergic interneuron projections to dopamine neuron axons in the striatum may play a major role in the effects of nicotine. Moreover, an indirect mesocorticolimbic feedback loop involving the medial prefrontal cortex may be involved in behavioral characteristics of nicotine addiction. Therefore, this review will highlight current understanding of the effects of nicotine on the function of mesolimbic and mesocortical dopamine projections in the mesocorticolimbic circuit.
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Affiliation(s)
- Sybren F de Kloet
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cogntive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cogntive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.
| | - Taco J De Vries
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cogntive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands; Department of Anatomy and Neurosciences, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
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18
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Cole RD, Poole RL, Guzman DM, Gould TJ, Parikh V. Contributions of β2 subunit-containing nAChRs to chronic nicotine-induced alterations in cognitive flexibility in mice. Psychopharmacology (Berl) 2015; 232:1207-17. [PMID: 25281224 PMCID: PMC4361240 DOI: 10.1007/s00213-014-3754-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/21/2014] [Indexed: 12/16/2022]
Abstract
RATIONALE Deficits in executive functions underlie compulsive drug use, and understanding how nicotine influences these cognitive processes may provide important information on neurobiological substrates of nicotine addiction. Accumulating evidence suggests that β2 subunit-containing nicotinic receptors (nAChRs) are involved in the reinforcing process of nicotine addiction. Whether these nAChRs also contributes to the detrimental effects of chronic nicotine on flexible decision-making is not known. OBJECTIVES In the present study, the effects of chronic nicotine were assessed in mice with partial or complete deletion of the β2 subunit-containing nAChR gene (β2+/- or β2-/-) performing an operant cognitive flexibility task. RESULTS Visual discrimination learning was not affected in saline-treated β2 nAChR mutants as compared to the wild-type (β2+/+) mice; yet, chronic nicotine facilitated acquisition of visual discrimination in all genotypes. The acquisition of new egocentric response strategy set-shifting remained similar in all genotypes, and there was no effect of treatment. Chronic nicotine treatment impaired reversal learning in β2+/+ mice by increasing response perseveration to the previously rewarded stimulus. Moreover, the acquisition of inverted stimulus-reward contingencies did not differ between β2+/+ and β2-/- mice exposed to chronic nicotine. Interestingly, nicotine-induced reversal learning deficits were not observed in β2+/- mice. CONCLUSIONS Collectively, these findings suggest that β2 subunit-containing nAChRs are not critical for visual discrimination learning and extra dimensional rule shift. However, sustained activation of these nAChRs with nicotine may interfere with inhibitory control processes influencing affective shifts in stimulus-reward contingencies.
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Affiliation(s)
| | | | | | | | - Vinay Parikh
- Corresponding author: Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122. Phone: 215-204-1572,
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Burke DA, Heshmati P, Kholdebarin E, Levin ED. Decreasing nicotinic receptor activity and the spatial learning impairment caused by the NMDA glutamate antagonist dizocilpine in rats. Eur J Pharmacol 2014; 741:132-9. [PMID: 25064338 PMCID: PMC4184962 DOI: 10.1016/j.ejphar.2014.07.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 12/12/2022]
Abstract
Nicotinic systems have been shown by a variety of studies to be involved in cognitive function. Nicotinic receptors have an inherent property to become desensitized after activation. The relative role of nicotinic receptor activation vs. net receptor inactivation by desensitization in the cognitive effects of nicotinic drugs remains to be fully understood. In these studies, we tested the effects of the α7 nicotinic receptor antagonist methyllycaconitine (MLA), the α4β2 nicotinic receptor antagonist dihydro-β-erythroidine (DHβE), the nonspecific nicotinic channel blocker mecamylamine and the α4β2 nicotinic receptor desensitizing agent sazetidine-A on learning in a repeated acquisition test. Adult female Sprague-Dawley rats were trained on a repeated acquisition learning procedure in an 8-arm radial maze. MLA (1-4mg/kg), DHβE (1-4mg/kg), mecamylamine (0.125-0.5mg/kg) or sazetidine-A (1 and 3mg/kg) were administered in four different studies either alone or together with the NMDA glutamate antagonist dizocilpine (0.05 and 0.10mg/kg). MLA significantly counteracted the learning impairment caused by dizocilpine. The overall choice accuracy impairment caused by dizocilpine was significantly attenuated by co-administration of DHβE. Low doses of the non-specific nicotinic antagonist mecamylamine also reduced dizocilpine-induced repeated acquisition impairment. Sazetidine-A reversed the accuracy impairment caused by dizocilpine. These studies provide evidence that a net decrease in nicotinic receptor activity can improve learning by attenuating learning impairment induced by NMDA glutamate blockade. This adds to evidence in cognitive tests that nicotinic antagonists can improve cognitive function. Further research characterizing the efficacy and mechanisms underlying nicotinic antagonist and desensitization induced cognitive improvement is warranted.
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20
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Di Giorgio A, Smith RM, Fazio L, D'Ambrosio E, Gelao B, Tomasicchio A, Selvaggi P, Taurisano P, Quarto T, Masellis R, Rampino A, Caforio G, Popolizio T, Blasi G, Sadee W, Bertolino A. DRD2/CHRNA5 interaction on prefrontal biology and physiology during working memory. PLoS One 2014; 9:e95997. [PMID: 24819610 PMCID: PMC4018353 DOI: 10.1371/journal.pone.0095997] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 04/01/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Prefrontal behavior and activity in humans are heritable. Studies in animals demonstrate an interaction between dopamine D2 receptors and nicotinic acetylcholine receptors on prefrontal behavior but evidence in humans is weak. Therefore, we hypothesize that genetic variation regulating dopamine D2 and nicotinic acetylcholine receptor signaling impact prefrontal cortex activity and related cognition. To test this hypothesis in humans, we explored the interaction between functional genetic variants in the D2 receptor gene (DRD2, rs1076560) and in the nicotinic receptor α5 gene (CHRNA5, rs16969968) on both dorsolateral prefrontal cortex mediated behavior and physiology during working memory and on prefrontal gray matter volume. METHODS A large sample of healthy subjects was compared for genotypic differences for DRD2 rs1076560 (G>T) and CHNRA5 rs16969968 (G>A) on prefrontal phenotypes, including cognitive performance at the N-Back task, prefrontal physiology with BOLD fMRI during performance of the 2-Back working memory task, and prefrontal morphometry with structural MRI. RESULTS We found that DRD2 rs1076560 and CHNRA5 rs16969968 interact to modulate cognitive function, prefrontal physiology during working memory, and prefrontal gray matter volume. More specifically, CHRNA5-AA/DRD2-GT subjects had greater behavioral performance, more efficient prefrontal cortex activity at 2Back working memory task, and greater prefrontal gray matter volume than the other genotype groups. CONCLUSIONS The present data extend previous studies in animals and enhance our understanding of dopamine and acetylcholine signaling in the human prefrontal cortex, demonstrating interactions elicited by working memory that are modulated by genetic variants in DRD2 and CHRNA5.
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Affiliation(s)
| | - Ryan M. Smith
- Department of Pharmacology, Center for Pharmacogenomics, The Ohio State University, Columbus, Ohio, United States of America
| | - Leonardo Fazio
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Enrico D'Ambrosio
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Barbara Gelao
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Aldo Tomasicchio
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Pierluigi Selvaggi
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Paolo Taurisano
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Tiziana Quarto
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
- Cognitive Brain Research Unit, Department of Behavioral Sciences, University of Helsinki, Helsinki, Finland
| | - Rita Masellis
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Antonio Rampino
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Grazia Caforio
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Teresa Popolizio
- IRCCSS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Italy
| | - Giuseppe Blasi
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
| | - Wolfgang Sadee
- Department of Pharmacology, Center for Pharmacogenomics, The Ohio State University, Columbus, Ohio, United States of America
| | - Alessandro Bertolino
- IRCCSS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Italy
- Group of Psychiatric Neuroscience, Department of Basic Medical Science, Neuroscience and Sense Organs, Aldo Moro University, Bari, Italy
- pRED, NORD DTA, F. Hoffman-La Roche Ltd., Basel, Switzerland
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Gold PE, Korol DL. Forgetfulness during aging: an integrated biology. Neurobiol Learn Mem 2014; 112:130-8. [PMID: 24674745 DOI: 10.1016/j.nlm.2014.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/10/2014] [Accepted: 03/13/2014] [Indexed: 01/07/2023]
Abstract
Age-related impairments in memory are often attributed to failures, at either systems or molecular levels, of memory storage processes. A major characteristic of changes in memory with increasing age is the advent of forgetfulness in old vs. young animals. This review examines the contribution of a dysfunction of the mechanisms responsible for modulating the maintenance of memory in aged rats. A memory-modulating system that includes epinephrine, acting through release of glucose from liver glycogen stores, potently enhances memory in young rats. In old rats, epinephrine loses its ability to release glucose and loses its efficacy in enhancing memory. Brain measures of extracellular levels of glucose in the hippocampus during memory testing show decreases in glucose in both young and old rats, but the decreases are markedly greater in extent and duration in old rats. Importantly, the old rats do not have the ability to increase blood glucose levels in response to arousal-related epinephrine release, which is retained and even increased in aged rats. Glucose appears to be able to reverse fully the increased rate of forgetting seen in old rats. This set of findings suggests that physiological mechanisms outside of the brain, i.e. changes in neuroendocrine functions, may contribute substantially to the onset of rapid forgetting in aged animals.
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Affiliation(s)
- Paul E Gold
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States.
| | - Donna L Korol
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States
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Perumal E, Paul V, Govindarajan V, Panneerselvam L. A brief review on experimental fluorosis. Toxicol Lett 2013; 223:236-51. [DOI: 10.1016/j.toxlet.2013.09.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/06/2013] [Accepted: 09/08/2013] [Indexed: 01/17/2023]
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Coura RS, Cressant A, Xia J, de Chaumont F, Olivo-Marin JC, Pelloux Y, Dalley JW, Granon S. Nonaggressive and adapted social cognition is controlled by the interplay between noradrenergic and nicotinic receptor mechanisms in the prefrontal cortex. FASEB J 2013; 27:4343-54. [PMID: 23882123 PMCID: PMC3977319 DOI: 10.1096/fj.13-231084] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/24/2013] [Indexed: 02/02/2023]
Abstract
Social animals establish flexible behaviors and integrated decision-making processes to adapt to social environments. Such behaviors are impaired in all major neuropsychiatric disorders and depend on the prefrontal cortex (PFC). We previously showed that nicotinic acetylcholine receptors (nAChRs) and norepinephrine (NE) in the PFC are necessary for mice to show adapted social cognition. Here, we investigated how the cholinergic and NE systems converge within the PFC to modulate social behavior. We used a social interaction task (SIT) in C57BL/6 mice and mice lacking β2*nAChRs (β2(-/-) mice), making use of dedicated software to analyze >20 social sequences and pinpoint social decisions. We performed specific PFC NE depletions before SIT and measured monoamines and acetylcholine (ACh) levels in limbic corticostriatal circuitry. After PFC-NE depletion, C57BL/6 mice exhibited impoverished and more rigid social behavior and were 6-fold more aggressive than sham-lesioned animals, whereas β2(-/-) mice showed unimpaired social behavior. Our biochemical measures suggest a critical involvement of DA in SIT. In addition, we show that the balance between basal levels of monoamines and of ACh modulates aggressiveness and this modulation requires functional β2*nAChRs. These findings demonstrate the critical interplay between prefrontal NE and nAChRs for the development of adapted and nonaggressive social cognition.
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Affiliation(s)
- Renata S Coura
- 3Centre de Neuroscience Paris Sud, UMR 8195, Université Paris Sud, Orsay, 91405.
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Effects of an alpha7 nicotinic receptor agonist and stress on spatial memory in an animal model of Alzheimer's disease. BIOMED RESEARCH INTERNATIONAL 2013; 2013:952719. [PMID: 24058919 PMCID: PMC3766554 DOI: 10.1155/2013/952719] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 01/23/2023]
Abstract
The aim of the present study was to test the effects of PNU-282987 on spatial learning and memory and hippocampal neurogenesis in both intact and chronically stressed transgenic mice. Transgenic mice with susceptibility to Alzheimer's disease (AD) under immobilization stress and not-stressed animals receiving 0 and 1 mg/kg of PNU-282987 (PNU) were evaluated in a water maze task. The effects of PNU and stress on proliferation of new cells in the hippocampus of these animals were also assessed. The latency to escape the platform was significantly higher in transgenic stressed mice compared to those in the wild stressed group, as well as in transgenic animals without PNU compared to control wild group. On retention of the task, differences emerged on stressed wild animals, PNU wild group, and stressed wild mice receiving PNU. However, no significant differences were detected on new cell proliferation. The results of the present study did not show any impact of stress in acquisition of a spatial task both in wild and transgenic mice. No clear effects of PNU on acquisition of a spatial task in transgenic mice with susceptibility to AD were detected. Although PNU and stress effects were detected on retention of the task in wild animals, no changes were noted in transgenic mice.
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Harel BT, Pietrzak RH, Snyder PJ, Maruff P. Effect of cholinergic neurotransmission modulation on visual spatial paired associate learning in healthy human adults. Psychopharmacology (Berl) 2013; 228:673-83. [PMID: 23568575 DOI: 10.1007/s00213-013-3072-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Accepted: 03/09/2013] [Indexed: 01/21/2023]
Abstract
RATIONALE Use of cross-species neuropsychological paradigms such as visual-spatial paired associate learning (PAL) may allow for a better understanding of underlying neural substrates of memory. Such paradigms, which are often used to guide models of memory in animals, can then be carried forward into humans to provide a basis for evaluation of pharmacologic compounds designed to ameliorate learning and memory impairments in neurologic and psychiatric morbidities. OBJECTIVES This double-blind, randomized, crossover trial investigated effects of donepezil, an acetylcholinesterase (AChE) inhibitor, in attenuating scopolamine-induced cognitive impairment using a novel, "process-based" computerized measure of visual-spatial PAL. RESULTS In healthy male volunteers, scopolamine (0.6 mg) induced a time-dependent reduction in visual-spatial PAL, with the greatest impairment (Cohen's d = 1.37) observed 2 h after dosing. Cotreatment with donepezil (10 mg) significantly ameliorated scopolamine-induced impairment at the 2-h time point (Cohen's d = 0.66). Process-based analyses revealed a significant impairment in both memory (Cohen's d = 1.37 to 0.50) and executive (Cohen's d = 1 .21 to 0.62) aspects of visual-spatial PAL performance following acute scopolamine challenge, and these reductions were ameliorated by donepezil. CONCLUSIONS Acute scopolamine challenge can produce large and robust deficits in visual-spatial PAL, which reflect impairments in both memory and executive processes. Coadministration of a single dose of donepezil can ameliorate these deficits. These results provide support for the use of a visual-spatial PAL test as a pharmacodynamic cognitive marker of central nervous system (CNS)-mediating compounds in humans.
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Affiliation(s)
- Brian T Harel
- CogState, Ltd, 195 Church St., 8th Floor, New Haven, CT 06510, USA.
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Young JW, Geyer MA. Evaluating the role of the alpha-7 nicotinic acetylcholine receptor in the pathophysiology and treatment of schizophrenia. Biochem Pharmacol 2013; 86:1122-32. [PMID: 23856289 DOI: 10.1016/j.bcp.2013.06.031] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/27/2013] [Accepted: 06/28/2013] [Indexed: 12/16/2022]
Abstract
The group of schizophrenia disorders affects approximately 1% of the population and has both genetic and environmental etiologies. Sufferers report various behavioral abnormalities including hallucinations and delusions (positive symptoms), reduced joy and amotivation (negative symptoms), plus inattention and poor learning (cognitive deficits). Despite the heterogeneous symptoms experienced, most patients smoke. The self-medication hypothesis posits that patients smoke to alleviate symptoms, consistent with evidence for nicotine-induced enhancement of cognition. While nicotine acts on multiple nicotinic acetylcholine receptors (nAChRs), the primary target of research is often the homomeric α7 nAChR. Given genetic linkages between schizophrenia and this receptor, its association with P50 sensory gating deficits, and its reduced expression in post-mortem brains, many have attempted to develop α7 nAChR ligands for treating schizophrenia. Recent evidence that ligands can be orthosteric agonists or positive allosteric modulators (PAMs) has revitalized the hope for treatment discovery. Herein, we present evidence regarding: (1) pathophysiological alterations of α7 nAChRs that might occur in patients; (2) mechanistic evidence for the normal action of α7 nAChRs; (3) preclinical studies using α7 nAChR orthosteric agonists and type I/II PAMs; and (4) where successful translational testing has occurred for particular compounds, detailing what is still required. We report that the accumulating evidence is positive, but that greater work is required using positron emission tomography to understand current alterations in α7 nAChR expression and their relationship to symptoms. Finally, cross-species behavioral tasks should be used more regularly to determine the predictive efficacy of treatments.
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Affiliation(s)
- Jared W Young
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0804, United States; Research Service, San Diego Veteran's Affairs Hospital, 3350 La Jolla Drive, San Diego, CA 92037, United States.
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Pandya AA, Yakel JL. Activation of the α7 nicotinic ACh receptor induces anxiogenic effects in rats which is blocked by a 5-HT₁a receptor antagonist. Neuropharmacology 2013; 70:35-42. [PMID: 23321689 PMCID: PMC3640667 DOI: 10.1016/j.neuropharm.2013.01.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 12/19/2012] [Accepted: 01/06/2013] [Indexed: 12/13/2022]
Abstract
The α7 nicotinic acetylcholine receptor (nAChR) is highly expressed in different regions of the brain and is associated with cognitive function as well as anxiety. Agonists and positive allosteric modulators (PAMs) of the α7 subtype of nAChRs have been shown to improve cognition. Previously nicotine, which activates both α7 and non-α7 subtypes of nAChRs, has been shown to have an anxiogenic effect in behavioral tests. In this study, we compared the effects of the α7-selective agonist (PNU-282987) and PAM (PNU-120596) in a variety of behavioral tests in Sprague Dawley rats to look at their effects on learning and memory as well as anxiety. We found that neither PNU-282987 nor PNU-120596 improved spatial-learning or episodic memory by themselves. However when cognitive impairment was induced in the rats with scopolamine (1 mg/kg), both PNU-120596 and PNU-282987 were able to reverse this memory impairment and restore it back to normal levels. While PNU-120596 reversed the scopolamine-induced cognitive impairment, it did not have any adverse effect on anxiety. PNU-282987 on the other hand displayed an increase in anxiety-like behavior at a higher dose (10 mg/kg) that was significantly reduced by the serotonin 5-HT₁a receptor antagonist WAY-100135. However the α7 receptor antagonist methyllycaconitine was unable to reverse these anxiety-like effects seen with PNU-282987. These results suggest that α7 nAChR PAMs are pharmacologically advantageous over agonists, and should be considered for further development as therapeutic drugs targeting the α7 receptors.
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Affiliation(s)
- Anshul A Pandya
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, MD F2-08, PO Box 12233, NC 27709, USA.
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Kroker KS, Moreth J, Kussmaul L, Rast G, Rosenbrock H. Restoring long-term potentiation impaired by amyloid-beta oligomers: Comparison of an acetylcholinesterase inhibitior and selective neuronal nicotinic receptor agonists. Brain Res Bull 2013; 96:28-38. [DOI: 10.1016/j.brainresbull.2013.04.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/12/2013] [Accepted: 04/15/2013] [Indexed: 12/25/2022]
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Effects of L-arginine and N(ω)-nitro-L-arginine methylester on learning and memory and α7 nAChR expression in the prefrontal cortex and hippocampus of rats. Neurosci Bull 2013; 29:303-10. [PMID: 23575895 DOI: 10.1007/s12264-013-1331-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 10/23/2012] [Indexed: 12/22/2022] Open
Abstract
Nitric oxide (NO) is a novel type of neurotransmitter that is closely associated with synaptic plasticity, learning and memory. In the present study, we assessed the effects of L-arginine and N(ω)-nitro-L-arginine methylester (L-NAME, a nitric oxide synthase inhibitor) on learning and memory. Rats were assigned to three groups receiving intracerebroventricular injections of L-Arg (the NO precursor), L-NAME, or 0.9% NaCl (control), once daily for seven consecutive days. Twelve hours after the last injection, they underwent an electric shock-paired Y maze test. Twenty-four hours later, the rats' memory of the safe illuminated arm was tested. After that, the levels of NO and α7 nicotinic acetylcholine receptor (α7 nAChR) in the prefrontal cortex and hippocampus were assessed using an NO assay kit, and immunohistochemistry and Western blots, respectively. We found that, compared to controls, L-Arg-treated rats received fewer foot shocks and made fewer errors to reach the learning criterion, and made fewer errors during the memory-testing session. In contrast, L-NAME-treated rats received more foot shocks and made more errors than controls to reach the learning criterion, and made more errors during the memory-testing session. In parallel, NO content in the prefrontal cortex and hippocampus was higher in L-Arg-treated rats and lower in L-NAME rats, compared to controls. Similarly, α7 nAChR immunoreactivity and protein expression in the prefrontal cortex and hippocampus were higher in L-Arg-treated rats and lower in L-NAME rats, compared to controls. These results suggest that the modulation of NO content in the brain correlates with α7 nAChR distribution and expression in the prefrontal cortex and hippocampus, as well as with learning and memory performance in the Y-maze.
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Morris KA, Li S, Bui DD, Gold PE. Glucose attenuates impairments in memory and CREB activation produced by an α4β2 but not an α7 nicotinic receptor antagonist. Neuropharmacology 2013; 67:233-42. [PMID: 23164619 PMCID: PMC3562370 DOI: 10.1016/j.neuropharm.2012.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 10/30/2012] [Accepted: 11/04/2012] [Indexed: 12/24/2022]
Abstract
Glucose improves memory for a variety of tasks when administered to rats and mice near the time of training. Prior work indicates glucose may enhance memory by increasing the synthesis and release of the neurotransmitter acetylcholine in the brain. To investigate if specific acetylcholine receptor subtypes may mediate some of the memory-enhancing actions of glucose, we examined the effects of subtype-specific nicotinic acetylcholine receptor antagonists on memory in Fischer-344 rats and also examined the ability of glucose to reverse drug-induced impairments. Pre-training peripheral injections of methyllycaconitine (MLA) or dihydro-beta-erythroidine (DHβE), which are specific α7 and α4β2 nicotinic receptor antagonists, respectively, dose-dependently impaired retention latencies in an inhibitory avoidance task when tested 7-days but not 1 h after training. Immediate post-training glucose injections attenuated the impairments, but were more effective in attenuating the DHβE-induced impairments. Likewise, peripheral or direct intrahippocampal injections of MLA or DHβE dose-dependently impaired spatial working memory scores on a spontaneous alternation task. Concurrent administration of glucose reversed DHβE- but not MLA-induced impairments. CREB phosphorylation downstream of cholinergic signaling was assessed 30 min after spontaneous alternation testing and intrahippocampal drug infusions. Both MLA and DHβE impaired hippocampal CREB phosphorylation; glucose reversed DHβE- but not MLA-induced deficits. The effectiveness of glucose in reversing DHβE- but not MLA-induced impairments in behavioral performance and CREB phosphorylation suggests that activation of α7 receptors may play an important role in memory enhancement by glucose.
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Affiliation(s)
- Ken A. Morris
- Neuroscience Program and College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Sisi Li
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Duat D. Bui
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Paul E. Gold
- Department of Biology, Syracuse University, Syracuse, NY, United States
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Abstract
The precise role of nicotinic acetylcholine receptors (nAChRs) in central cognitive processes still remains incompletely understood almost 150 years after its initial discovery. Central nAChRs are activated by acetylcholine, which functions in the extracellular space as a nonsynaptic messenger. Recently, a novel concept in the nAChR mode of operation has been described as a fast-type nonsynaptic transmission. In this review, we attempt to summarise the experimental findings that support the role of one of the most distributed receptor subtypes, the α7 nAChRs, and particularly focus on its procognitive effects following receptor activation. The basic characteristics of α7 nAChRs are discussed, from receptor homology to cellular-level functions. Synaptic plasticity is often implicated with α7 nAChRs on the basis of several diverse studies. Here, we provide a summary of the plastic features of the α7 receptor subtype and its role in higher level cognitive function. Finally, recent clinical evidence is reviewed, which demonstrates with increasing confidence the promise α7 nAChRs as a molecular target in future pharmacotherapy to prevent cognitive decline in various types of dementia, specifically, via the development of positive allosteric modulator compounds.
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Affiliation(s)
- Balázs Lendvai
- Gedeon Richter Plc., Pharmacology and Drug Safety Department, Budapest, Gyömrői u, 19-21, Hungary.
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Mendez IA, Damborsky JC, Winzer-Serhan UH, Bizon JL, Setlow B. Α4β2 and α7 nicotinic acetylcholine receptor binding predicts choice preference in two cost benefit decision-making tasks. Neuroscience 2012; 230:121-31. [PMID: 23159316 DOI: 10.1016/j.neuroscience.2012.10.067] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/29/2012] [Accepted: 10/30/2012] [Indexed: 11/27/2022]
Abstract
Nicotinic receptors have been linked to a wide range of cognitive and behavioral functions, but surprisingly little is known about their involvement in cost benefit decision making. The goal of these experiments was to determine how nicotinic acetylcholine receptor (nAChR) expression is related to two forms of cost benefit decision making. Male Long Evans rats were tested in probability- and delay-discounting tasks, which required discrete trial choices between a small reward and a large reward associated with varying probabilities of omission and varying delays to reward delivery, respectively. Following testing, radioligand binding to α4β2 and α7 nAChR subtypes in brain regions implicated in cost benefit decision making was examined. Significant linear relationships were observed between choice of the large delayed reward in the delay discounting task and α4β2 receptor binding in both the dorsal and ventral hippocampus. Additionally, trends were found suggesting that choice of the large costly reward in both discounting tasks was inversely related to α4β2 receptor binding in the medial prefrontal cortex and nucleus accumbens shell. Similar trends suggested that choice of the large delayed reward in the delay discounting task was inversely related to α4β2 receptor binding in the orbitofrontal cortex, nucleus accumbens core, and basolateral amygdala, as well as to α7 receptor binding in the basolateral amygdala. These data suggest that nAChRs (particularly α4β2) play both unique and common roles in decisions that require consideration of different types of reward costs.
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Affiliation(s)
- I A Mendez
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA.
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McLean SL, Idris NF, Grayson B, Gendle DF, Mackie C, Lesage AS, Pemberton DJ, Neill JC. PNU-120596, a positive allosteric modulator of α7 nicotinic acetylcholine receptors, reverses a sub-chronic phencyclidine-induced cognitive deficit in the attentional set-shifting task in female rats. J Psychopharmacol 2012; 26:1265-70. [PMID: 22182741 DOI: 10.1177/0269881111431747] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The α7 nicotinic acetylcholine receptors (nAChRs) have been highlighted as a target for cognitive enhancement in schizophrenia. Adult female hooded Lister rats received sub-chronic phencyclidine (PCP) (2 mg/kg) or vehicle i.p. twice daily for 7 days, followed by 7 days' washout. PCP-treated rats then received PNU-120596 (10 mg/kg; s.c.) or saline and were tested in the attentional set-shifting task. Sub-chronic PCP produced a significant cognitive deficit in the extra-dimensional shift (EDS) phase of the task (p < 0.001, compared with vehicle). PNU-120596 significantly improved performance of PCP-treated rats in the EDS phase of the attentional set-shifting task (p < 0.001). In conclusion, these data demonstrate that PNU-120596 improves cognitive dysfunction in our animal model of cognitive dysfunction in schizophrenia, most likely via modulation of α7 nACh receptors.
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Gould RW, Garg PK, Garg S, Nader MA. Effects of nicotinic acetylcholine receptor agonists on cognition in rhesus monkeys with a chronic cocaine self-administration history. Neuropharmacology 2012; 64:479-88. [PMID: 22921923 DOI: 10.1016/j.neuropharm.2012.08.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/09/2012] [Accepted: 08/09/2012] [Indexed: 01/08/2023]
Abstract
Cocaine use is associated with impaired cognitive function, which may negatively impact treatment outcomes. One pharmacological strategy to improve cognition involves nicotinic acetylcholine receptor (nAChR) stimulation. However, the effects of chronic cocaine exposure on nAChR distribution and function have not been characterized. Thus, one goal of this study was to examine nAChR availability in rhesus monkeys with an extensive cocaine self-administration history (n = 4; ~6 years, mean intake, 1463 mg/kg) compared to age-matched cocaine-naive control monkeys (n = 5). Using [¹¹C]-nicotine and positron emission tomography (PET) imaging, cocaine-experienced monkeys showed significantly higher receptor availability in the hippocampus compared to cocaine-naive monkeys. A second goal was to examine the effects of nAChR agonists on multiple domains of cognitive performance in these same monkeys. For these studies, working memory was assessed using a delayed match-to-sample (DMS) task, associative learning and behavioral flexibility using stimulus discrimination and reversal learning tasks. When administered acutely, the nonselective high-efficacy agonist nicotine, the low-efficacy α4β2* subtype-selective agonist varenicline and the high-efficacy α7 subtype-selective agonist, PNU-282987 significantly improved DMS performance in both cocaine-naive and cocaine-experienced monkeys. Individual doses of nicotine and varenicline that engendered maximum cognitive enhancing effects on working memory did not affect discrimination or reversal learning, while PNU-282987 disrupted reversal learning in the cocaine-naive monkeys. These findings indicate that a cocaine self-administration history influenced nAChR distribution and the effects of nAChR agonists on cognitive performance, including a reduced sensitivity to the disrupting effects on reversal learning. The cognitive enhancing effects of nAChR agonists may be beneficial in combination with behavioral treatments for cocaine addiction. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Robert W Gould
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Newman EL, Gupta K, Climer JR, Monaghan CK, Hasselmo ME. Cholinergic modulation of cognitive processing: insights drawn from computational models. Front Behav Neurosci 2012; 6:24. [PMID: 22707936 PMCID: PMC3374475 DOI: 10.3389/fnbeh.2012.00024] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/21/2012] [Indexed: 11/20/2022] Open
Abstract
Acetylcholine plays an important role in cognitive function, as shown by pharmacological manipulations that impact working memory, attention, episodic memory, and spatial memory function. Acetylcholine also shows striking modulatory influences on the cellular physiology of hippocampal and cortical neurons. Modeling of neural circuits provides a framework for understanding how the cognitive functions may arise from the influence of acetylcholine on neural and network dynamics. We review the influences of cholinergic manipulations on behavioral performance in working memory, attention, episodic memory, and spatial memory tasks, the physiological effects of acetylcholine on neural and circuit dynamics, and the computational models that provide insight into the functional relationships between the physiology and behavior. Specifically, we discuss the important role of acetylcholine in governing mechanisms of active maintenance in working memory tasks and in regulating network dynamics important for effective processing of stimuli in attention and episodic memory tasks. We also propose that theta rhythm plays a crucial role as an intermediary between the physiological influences of acetylcholine and behavior in episodic and spatial memory tasks. We conclude with a synthesis of the existing modeling work and highlight future directions that are likely to be rewarding given the existing state of the literature for both empiricists and modelers.
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Affiliation(s)
- Ehren L. Newman
- Center for Memory and Brain, Boston University, BostonMA, USA
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dos Santos Coura R, Granon S. Prefrontal neuromodulation by nicotinic receptors for cognitive processes. Psychopharmacology (Berl) 2012; 221:1-18. [PMID: 22249358 DOI: 10.1007/s00213-011-2596-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/17/2011] [Indexed: 11/30/2022]
Abstract
RATIONALE The prefrontal cortex (PFC) mediates executive functions, a set of control processes that optimize performance on cognitive tasks. It enables appropriate decision-making and mediates adapted behaviors, all processes impaired in psychiatric or degenerative disorders. Key players of normal functioning of the PFC are neurotransmitter (NT) systems arising from subcortical nuclei and targeting PFC subareas and, also, neuronal nicotinic acetylcholine receptors (nAChRs). These ion channels, located on multiple cell compartments in all brain areas, mediate direct cholinergic transmission and modulate the release of NTs that cross onto PFC neurons or interneurons. OBJECTIVE We compiled current knowledge concerning the role of nAChRs in NT release, focusing on the PFC. We point out plausible mechanisms of interaction among PFC circuits implicated in executive functions and emphasized the role of β2-containing nAChRs, the high-affinity receptors for acetylcholine (ACh). These receptors are more directly implicated in behavioral flexibility either when located on PFC neurons or in the monoaminergic or cholinergic systems targeting the PFC. RESULTS We shed light on potentially crucial roles played by nAChRs in complex interactions between local and afferent NTs. We show how they could act on cognition via PFC networks. CONCLUSIONS nAChRs are crucial for decision-making, during integration of emotional and motivational features, both mediated by different NT pathways in the PFC. We review the knowledge recently gained on cognitive functions in mice and our current understanding of PFC NT modulation. The combination of these data is expected to provide new hypotheses concerning the role of AChRs in cognitive processes.
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Abstract
PURPOSE OF REVIEW Cognitive abilities are established as major deficits in those with schizophrenia and represent significant impediments toward successful psychosocial functioning within the community. Pharmacological treatments have historically focused on reducing the positive and negative symptoms of schizophrenia, with recent increased attention to developing agents to improve cognition as a treatment outcome. This review will highlight the recent advances in developing agents that act at neuronal α7 nicotinic acetylcholine receptors (nAChRs). RECENT FINDINGS A number of agents have demonstrated improvements in cognitive deficits in studies using both preclinical and clinical models. Evidence suggests that α7 nAChR activation impacts rule acquisition and initial learning in preclinical models. Preclinical studies indicate improved spatial working memory and reversal of phencyclidine-induced learning and memory deficits. Clinical studies indicate normalization of neuronal default network activity using functional magnetic resonance imaging methods. In addition, research on new agents developed to improve cognition suggests improved cognitive functioning in multiple domains (e.g., attention, memory, executive functioning, sensory gating and overall cognition) and promising safety profiles of additional agents. SUMMARY Improvements in cognitive functioning within preclinical and clinical studies of schizophrenia are evident through the use of α7 nAChR agonists, while positive allosteric modulators may gain increased attention in the future.
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Ashare RL, McKee SA. Effects of varenicline and bupropion on cognitive processes among nicotine-deprived smokers. Exp Clin Psychopharmacol 2012; 20:63-70. [PMID: 21942262 PMCID: PMC3640636 DOI: 10.1037/a0025594] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nicotine deprivation is associated with craving, negative affect, and difficulty concentrating, which may contribute to subsequent relapse. Bupropion and varenicline are both effective treatments for smoking cessation, and evidence from clinical trials suggests that these treatments increase abstinence rates. However, the mechanism by which these medications reduce relapse remains unclear. Recent research has focused on cognitive processes, such as attention and working memory, which may predict relapse. In addition, there may also be sex differences in cognitive-related deficits during nicotine deprivation. The current sample consisted of 58 (22 females) daily smokers (at least 10 cigarettes per day) randomized to receive bupropion (300 mg/day), varenicline (2 mg/day), or placebo. After a 1-week run-up phase, participants completed a 9.5-hr laboratory session after overnight abstinence (CO verified). Participants completed measures of attention (Conners' Continuous Performance Task [CPT]), working memory (digits backward), and delay discounting. Measures of craving, withdrawal, and mood were also collected. Between-subjects ANCOVA models revealed that varenicline speeded reaction time, but reduced accuracy on the CPT compared with placebo. Sex moderated the effect of bupropion compared with placebo on working memory and delay discounting. Bupropion enhanced working memory for females but not males, and this pattern was reversed for delay discounting. The current data highlight the complex processes associated with nicotine deprivation and the need for future research to examine whether cognitive-related deficits are related to relapse. Identifying these mechanisms may help in the development of new pharmacological treatments.
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Affiliation(s)
- Rebecca L Ashare
- Department of Psychiatry, Yale University School of Medicine, USA.
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Beckel JM, Birder LA. Differential expression and function of nicotinic acetylcholine receptors in the urinary bladder epithelium of the rat. J Physiol 2012; 590:1465-80. [PMID: 22250215 DOI: 10.1113/jphysiol.2011.226860] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
It has been previously determined that the epithelial lining of the urinary bladder, or urothelium, expresses two subtypes of nicotinic acetylcholine receptors (nAChRs) that mediate distinct physiological effects in vivo. These effects include inhibition of bladder reflexes through α7 receptors and an excitation of bladder reflexes through α3-containing (α3*) receptors. It is believed that urothelial receptors mediate their effects through modulating the release of neurotransmitters such as ATP that subsequently influence bladder afferent nerve excitability. Therefore, we examined the distribution of nAChRs in the urothelium, as well as their ability to influence the release of the neurotransmitter ATP. Immunofluorescent staining of both whole bladder tissue and primary urothelial cultures from the rat demonstrated that the urothelium contains both α3* and α7 receptors. In primary urothelial cultures, α7 stimulation with choline (10 μM to 1 mM) caused a decrease in basal ATP release while α3* stimulation with cytisine (1–100 μM) caused a concentration-dependent, biphasic response, with low concentrations (1–10 μM) inhibiting release and higher concentrations (50–100 μM) increasing release. These responses were mirrored in an in vitro, whole bladder preparation. In vivo, excitation of bladder reflexes in response to intravesical cytisine (100 μM) is blocked by systemic administration of the purinergic antagonist PPADS (1 or 3 μg kg(−1)). We also examined how each receptor subtype influenced intracellular Ca2+ levels in cultured urothelial cells. nAChR stimulation increased [Ca2+]i through distinct mechanisms: α7 through a ryanodine-sensitive intracellular mechanism and α3* through extracellular influx. In addition, our findings suggest interactions between nAChR subtypes whereby activation of α7 receptors inhibited the response to a subsequent activation of α3* receptors, preventing the increase in [Ca2+]i previously observed. This inhibitory effect appears to be mediated through protein kinase A- or protein kinase C-mediated pathways.
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Affiliation(s)
- Jonathan M Beckel
- Department of Pharmacology and Biological Chemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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Muscarinic and nicotinic acetylcholine receptor agonists and allosteric modulators for the treatment of schizophrenia. Neuropsychopharmacology 2012; 37:16-42. [PMID: 21956443 PMCID: PMC3238081 DOI: 10.1038/npp.2011.199] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Muscarinic and nicotinic acetylcholine (ACh) receptors (mAChRs and nAChRs) are emerging as important targets for the development of novel treatments for the symptoms associated with schizophrenia. Preclinical and early proof-of-concept clinical studies have provided strong evidence that activators of specific mAChR (M(1) and M(4)) and nAChR (α(7) and α(2)β(4)) subtypes are effective in animal models of antipsychotic-like activity and/or cognitive enhancement, and in the treatment of positive and cognitive symptoms in patients with schizophrenia. While early attempts to develop selective mAChR and nAChR agonists provided important preliminary findings, these compounds have ultimately failed in clinical development due to a lack of true subtype selectivity and subsequent dose-limiting adverse effects. In recent years, there have been major advances in the discovery of highly selective activators for the different mAChR and nAChR subtypes with suitable properties for optimization as potential candidates for clinical trials. One novel strategy has been to identify ligands that activate a specific receptor subtype through actions at sites that are distinct from the highly conserved ACh-binding site, termed allosteric sites. These allosteric activators, both allosteric agonists and positive allosteric modulators, of mAChR and nAChR subtypes demonstrate unique mechanisms of action and high selectivity in vivo, and may provide innovative treatment strategies for schizophrenia.
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Kroker KS, Rast G, Rosenbrock H. Differential effects of subtype-specific nicotinic acetylcholine receptor agonists on early and late hippocampal LTP. Eur J Pharmacol 2011; 671:26-32. [PMID: 21968142 DOI: 10.1016/j.ejphar.2011.09.167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/13/2011] [Accepted: 09/15/2011] [Indexed: 01/14/2023]
Abstract
Brain nicotinic acetylcholine receptors are involved in several neuropsychiatric disorders, e.g. Alzheimer's and Parkinson's diseases, Tourette's syndrome, schizophrenia, depression, autism, attention deficit hyperactivity disorder, and anxiety. Currently, approaches selectively targeting the activation of specific nicotinic acetylcholine receptors are in clinical development for treatment of memory impairment of Alzheimer's disease patients. These are α4β2 and α7 nicotinic acetylcholine receptor agonists which are believed to enhance cholinergic and glutamatergic neurotransmission, respectively. In order to gain a better insight into the mechanistic role of these two nicotinic acetylcholine receptors in learning and memory, we investigated the effects of the α4β2 nicotinic acetylcholine receptor agonist TC-1827 and the α7 nicotinic acetylcholine receptor partial agonist SSR180711 on hippocampal long-term potentiation (LTP), a widely accepted cellular experimental model of memory formation. Generally, LTP is distinguished in an early and a late form, the former being protein-synthesis independent and the latter being protein-synthesis dependent. TC-1827 was found to increase early LTP in a bell-shaped dose dependent manner, but did not affect late LTP. In contrast, the α7 nicotinic acetylcholine receptor partial agonist SSR180711 showed enhancing effects on both early and late LTP in a bell-shaped manner. Furthermore, SSR180711 not only increased early LTP, but also transformed it into late LTP, which was not observed with the α4β2 nicotinic acetylcholine receptor agonist. Therefore, based on these findings α7 nicotinic acetylcholine receptor (partial) agonists appear to exhibit stronger efficacy on memory improvement than α4β2 nicotinic acetylcholine receptor agonists.
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Affiliation(s)
- Katja S Kroker
- Boehringer Ingelheim Pharma GmbH & Co KG, Department of CNS Diseases Research, Birkendorfer Strasse 65, 88397 Biberach, Germany.
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Wallace TL, Porter RHP. Targeting the nicotinic alpha7 acetylcholine receptor to enhance cognition in disease. Biochem Pharmacol 2011; 82:891-903. [PMID: 21741954 DOI: 10.1016/j.bcp.2011.06.034] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/18/2011] [Accepted: 06/24/2011] [Indexed: 01/05/2023]
Abstract
A promising drug target currently under investigation to improve cognitive deficits in neuropsychiatric and neurological disorders is the neuronal nicotinic alpha7 acetylcholine receptor (α7nAChR). Improving cognitive impairments in diseases such as Alzheimer's (AD) and schizophrenia remains a large unmet medical need, and the α7nAChR has many properties that make it an attractive therapeutic target. The α7nAChR is a ligand gated ion channel that has particularly high permeability to Ca(2+) and is expressed in key brain regions involved in cognitive processes (e.g., hippocampus). The α7nAChRs are localized both pre-synaptically, where they can regulate neurotransmitter release, and post-synaptically where they can activate intracellular signaling cascades and influence downstream processes involved in learning and memory. In particular, activation of the α7nAChR with small molecule agonists enhances long-term potentiation, an in vitro model of synaptic plasticity, and improves performance across multiple cognitive domains in rodents, monkeys, and humans. Positive allosteric modulation of the α7nAChR offers an alternate approach to direct agonism that could prove to be particularly beneficial in certain disease populations where smoking nicotine is prevalent (e.g., schizophrenia) and could interfere with an orthosteric agonist approach. The current review focuses on the neurobiology of the α7nAChR, its role in cognition and the development status of some of the most promising molecules advancing for the treatment of cognitive dysfunction in disease.
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Affiliation(s)
- Tanya L Wallace
- Center for Neuroscience, SRI International, 333 Ravenswood Avenue, M/S 100-69, Menlo Park, CA 94025, USA.
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Graef S, Schönknecht P, Sabri O, Hegerl U. Cholinergic receptor subtypes and their role in cognition, emotion, and vigilance control: an overview of preclinical and clinical findings. Psychopharmacology (Berl) 2011; 215:205-29. [PMID: 21212938 DOI: 10.1007/s00213-010-2153-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 12/15/2010] [Indexed: 01/10/2023]
Abstract
RATIONALE The cholinergic system has long been linked to cognitive processes. Two main classes of acetylcholine (ACh) receptors exist in the human brain, namely muscarinic and nicotinic receptors, of which several subtypes occur. OBJECTIVES This review seeks to provide an overview of previous findings on the influence of cholinergic receptor manipulations on cognition in animals and humans, with particular emphasis on the role of selected cholinergic receptor subtypes. Furthermore, the involvement of these receptor subtypes in the regulation of emotion and brain electrical activity as measured by electroencephalography (EEG) shall be addressed since these domains are considered to be important modulators of cognitive functioning. RESULTS In regard to cognition, the muscarinic receptor subtypes have been implicated mainly in memory functions, but have also been linked to attentional processes. The nicotinic α7 receptor subtype is involved in working memory, whereas the α4β2* subtype has been linked to tests of attention. Both muscarinic and nicotinic cholinergic mechanisms play a role in modulating brain electrical activity. Nicotinic receptors have been strongly associated with the modulation of depression and anxiety. CONCLUSIONS Cholinergic receptor manipulations have an effect on cognition, emotion, and brain electrical activity as measured by EEG. Changes in cognition can result from direct cholinergic receptor manipulation or from cholinergically induced changes in vigilance or affective state.
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Affiliation(s)
- Susanne Graef
- Department of Psychiatry, University of Leipzig, Semmelweisstr. 10, 04103 Leipzig, Germany.
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Arnsten AFT. Prefrontal cortical network connections: key site of vulnerability in stress and schizophrenia. Int J Dev Neurosci 2011; 29:215-23. [PMID: 21345366 PMCID: PMC3115784 DOI: 10.1016/j.ijdevneu.2011.02.006] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 02/02/2011] [Accepted: 02/03/2011] [Indexed: 01/01/2023] Open
Abstract
The symptoms of schizophrenia involve profound dysfunction of the prefrontal cortex (PFC). PFC networks create our "mental sketch pad", and PFC dysfunction contributes to symptoms such as cognitive deficits, thought disorder, delusions and hallucinations. Neuropathological studies of schizophrenia have shown marked loss of dendritic spines in deep layer III, the sublayer where PFC microcircuits reside. The microcircuits consist of recurrent excitatory pyramidal cell networks that interconnect on spines, and excite each other via NMDA receptor signaling. The pyramidal cell persistent firing is sculpted by lateral inhibition from GABAergic basket and chandelier cells, thus creating tuned, persistent firing needed for accurate representational knowledge (i.e., working memory). The strength of pyramidal cell network connections is markedly and flexibly altered by intracellular signaling pathways in dendritic spines, a process called dynamic network connectivity (DNC). DNC proteins such as HCN channels are concentrated on dendritic spines in deep layer III. Under optimal conditions, network inputs to pyramidal cells are strengthened by noradrenergic alpha-2A inhibition of cAMP-HCN channel signaling, and sculpted by dopamine D1-cAMP-HCN channel weakening of inappropriate inputs. However, with stress exposure, high levels of cAMP-HCN channel signaling produces a collapse in network firing. With chronic stress exposure, spines reduce in size and are lost, and this process involves increased PKC signaling. Importantly, molecules that normally strengthen PFC networks connections and/or reverse the stress response, are often genetically altered in schizophrenia. As exposure to stress is a key factor in the precipitation of schizophrenic symptoms, these dysregulated signaling pathways in deep layer III may interact with already vulnerable circuitry to cause spine loss and the descent into illness.
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Affiliation(s)
- Amy F T Arnsten
- Department of Neurobiology, Yale Medical School, 333 Cedar St., New Haven, CT 06510, USA.
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Vicens P, Ribes D, Torrente M, Domingo JL. Behavioral effects of PNU-282987, an alpha7 nicotinic receptor agonist, in mice. Behav Brain Res 2010; 216:341-8. [PMID: 20728474 DOI: 10.1016/j.bbr.2010.08.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 12/20/2022]
Abstract
The cholinergic system is closely related to learning and memory processes, and its neurodegeneration seems to be involved in neurodegenerative and neuropsychiatric cognitive disorders in the elderly. Alpha7 nicotinic acetylcholine receptors (nAChRs) have recently been shown to mediate neuroprotection and enhance cognitive performance in a variety of tasks, suggesting that there may be a new target for the pharmacotherapy of cognitive deficiencies. In this study, we investigated the behavioral effects of the acute and sub-chronic administration of 0, 1, 3, and 5 mg/kg of PNU-282987 (PNU) on motor activity, anxiety and learning in open-field and Morris water maze tasks in mice. Our results showed that the highest dose of PNU (5 mg/kg) diminished motor activity in the open-field following 5 and 12 days of administration (acute and sub-chronic, respectively). No effects on the acquisition of the Morris water maze were observed. However, only 1 mg/kg of PNU administered just before training trials over a period of 5 days showed beneficial effects on the retention of the water maze when evaluated 4 h after water maze acquisition. Further studies are needed to clarify the effects on the cognitive performance and potential neuroprotection of these agents in an elderly population with slight or severe deficiency in learning and memory processes, and/or in animal models vulnerable to neurodegenerative disorders.
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Affiliation(s)
- Paloma Vicens
- Department of Psychology, IISPV, Universitat Rovira i Virgili, 43007 Tarragona, Spain.
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Konradsson-Geuken A, Gash CR, Alexander K, Pomerleau F, Huettl P, Gerhardt GA, Bruno JP. Second-by-second analysis of alpha 7 nicotine receptor regulation of glutamate release in the prefrontal cortex of awake rats. Synapse 2010; 63:1069-82. [PMID: 19637277 DOI: 10.1002/syn.20693] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
These experiments utilized an enzyme-based microelectrode selective for the second-by-second detection of extracellular glutamate to reveal the alpha 7-based nicotinic modulation of glutamate release in the prefrontal cortex (PFC) of freely moving rats. Rats received intracortical infusions of the nonselective nicotinic agonist nicotine (12.0 mM, 1.0 microg/0.4 microl) or the selective alpha 7 agonist choline (2.0 mM/0.4 microl). The selectivity of drug-induced glutamate release was assessed in subgroups of animals pretreated with the alpha 7 antagonist, alpha-bungarotoxin (alpha-BGT, 10 microM), or kynurenine (10 microM) the precursor of the astrocyte-derived, negative allosteric alpha 7 modulator kynurenic acid. Local administration of nicotine increased glutamate signals (maximum amplitude = 4.3 +/- 0.6 microM) that were cleared to baseline levels in 493 +/- 80 seconds. Pretreatment with alpha-BGT or kynurenine attenuated nicotine-induced glutamate by 61% and 60%, respectively. Local administration of choline also increased glutamate signals (maximum amplitude = 6.3 +/- 0.9 microM). In contrast to nicotine-evoked glutamate release, choline-evoked signals were cleared more quickly (28 +/- 6 seconds) and pretreatment with alpha-BGT or kynurenine completely blocked the stimulated glutamate release. Using a method that reveals the temporal dynamics of in vivo glutamate release and clearance, these data indicate a nicotinic modulation of cortical glutamate release that is both alpha 7- and non-alpha 7-mediated. Furthermore, these data may also provide a mechanism underlying the recent focus on alpha 7 full and partial agonists as therapeutic agents in the treatment of cortically mediated cognitive deficits in schizophrenia.
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Subtype-selective nicotinic agonists enhance olfactory working memory in normal rats: a novel use of the odour span task. Neurosci Lett 2010; 471:114-8. [PMID: 20083163 DOI: 10.1016/j.neulet.2010.01.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 01/02/2010] [Accepted: 01/06/2010] [Indexed: 11/22/2022]
Abstract
Nicotinic agonists have been shown to enhance performance in cognitive tasks based on attention and memory. The aim of this study was to use a test of olfactory working memory; the odour span task (OST) in rodents, to investigate the effects of subtype-specific nicotinic agonists on working memory in normal rats. Rats were trained in a non-matching to sample (NMTS) rule and then the full OST, which involved identifying a novel odour from an increasing number of presented odours. Male hooded Lister rats were treated with nicotine, selective nicotinic agonists or vehicle (saline). In order to validate the task, muscarinic and nicotinic receptor antagonists were also examined. Nicotine at both 0.05 and 0.1mg/kg significantly increased mean span length in the OST. The selective alpha 4 beta 2 nicotinic receptor agonist metanicotine (0.1mg/kg s.c.) and the selective alpha 7 nicotinic receptor agonist (R)-N-(1-azabicyclo[2.2.2]oct-3-yl)(5-(2-pyridyl)thiophene-2-carboxamide) (compound A, 10mg/kg i.p.) also improved performance. In contrast, mecamylamine and scopolamine significantly decreased mean span length. These findings suggest a role for the activation of both alpha 4 beta 2 and alpha 7 subtypes of neuronal nicotinic receptor in mediating enhancements of olfactory working memory capacity in normal, non-compromised rats. These nicotinic receptor subtypes may therefore prove to be useful targets for the development of novel treatments for neuropsychiatric disorders that involve cognitive dysfunction.
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Wu HQ, Pereira EFR, Bruno JP, Pellicciari R, Albuquerque EX, Schwarcz R. The astrocyte-derived alpha7 nicotinic receptor antagonist kynurenic acid controls extracellular glutamate levels in the prefrontal cortex. J Mol Neurosci 2009; 40:204-10. [PMID: 19690987 DOI: 10.1007/s12031-009-9235-2] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 07/20/2009] [Indexed: 11/29/2022]
Abstract
The cognitive deficits seen in schizophrenia patients are likely related to abnormal glutamatergic and cholinergic neurotransmission in the prefrontal cortex. We hypothesized that these impairments may be secondary to increased levels of the astrocyte-derived metabolite kynurenic acid (KYNA), which inhibits alpha7 nicotinic acetylcholine receptors (alpha7AChR) and may thereby reduce glutamate release. Using in vivo microdialysis in unanesthetized rats, we show here that nanomolar concentrations of KYNA, infused directly or produced in situ from its bioprecursor kynurenine, significantly decrease extracellular glutamate levels in the prefrontal cortex. This effect was prevented by the systemic administration of galantamine (3 mg/kg) but not by donepezil (2 mg/kg), indicating that KYNA blocks the allosteric potentiating site of the alpha7AChR, which recognizes galantamine but not donepezil as an agonist. In separate rats, reduction of prefrontal KYNA formation by (S)-4-ethylsulfonyl benzoylalanine, a specific inhibitor of KYNA synthesis, caused a significant elevation in extracellular glutamate levels. Jointly, our results demonstrate that fluctuations in endogenous KYNA formation bidirectionally influence cortical glutamate concentrations. These findings suggest that selective attenuation of cerebral KYNA production, by increasing glutamatergic tone, might improve cognitive function in individuals with schizophrenia.
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Affiliation(s)
- Hui-Qiu Wu
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
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Glutamate–Dopamine Crosstalk in the Rat Prefrontal Cortex is Modulated by Alpha7 Nicotinic Receptors and Potentiated by PNU-120596. J Mol Neurosci 2009; 40:172-6. [DOI: 10.1007/s12031-009-9232-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 07/20/2009] [Indexed: 11/25/2022]
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