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Jankauskaite L, Malinauskas M, Snipaitiene A. Effect of stimulated platelets in COVID-19 thrombosis: Role of alpha7 nicotinic acetylcholine receptor. Front Cardiovasc Med 2022; 9:1037369. [PMID: 36312286 PMCID: PMC9614055 DOI: 10.3389/fcvm.2022.1037369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 09/26/2022] [Indexed: 01/08/2023] Open
Abstract
Since early 2020, SARS-CoV-2-induced infection resulted in global pandemics with high morbidity, especially in the adult population. COVID-19 is a highly prothrombotic condition associated with subsequent multiorgan failure and lethal outcomes. The exact mechanism of the prothrombotic state is not well understood and might be multifactorial. Nevertheless, platelets are attributed to play a crucial role in COVID-19-associated thrombosis. To date, platelets' role was defined primarily in thrombosis and homeostasis. Currently, more focus has been set on their part in inflammation and immunity. Moreover, their ability to release various soluble factors under activation as well as internalize and degrade specific pathogens has been highly addressed in viral research. This review article will discuss platelet role in COVID-19-associated thrombosis and their role in the cholinergic anti-inflammatory pathway. Multiple studies confirmed that platelets display a hyperactivated phenotype in COVID-19 patients. Critically ill patients demonstrate increased platelet activation markers such as P-selectin, PF4, or serotonin. In addition, platelets contain acetylcholine and express α7 nicotinic acetylcholine receptors (α7nAchR). Thus, acetylcholine can be released under activation, and α7nAchR can be stimulated in an autocrine manner and support platelet function. α7 receptor is one of the most important mediators of the anti-inflammatory properties as it is associated with humoral and intrinsic immunity and was demonstrated to contribute to better outcomes in COVID-19 patients when under stimulation. Hematopoietic α7nAchR deficiency increases platelet activation and, in experimental studies, α7nAchR stimulation can diminish the pro-inflammatory state and modulate platelet reactiveness via increased levels of NO. NO has been described to inhibit platelet adhesion, activation, and aggregation. In addition, acetylcholine has been demonstrated to decrease platelet aggregation possibly by blocking the e p-38 pathway. SARS-CoV-2 proteins have been found to be similar to neurotoxins which can bind to nAChR and prevent the action of acetylcholine. Concluding, the platelet role in COVID-19 thrombotic events could be explained by their active function in the cholinergic anti-inflammatory pathway.
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Affiliation(s)
- Lina Jankauskaite
- Institute of Physiology and Pharmacology, Lithuanian University of Health Sciences, Kaunas, Lithuania,Department of Pediatrics, Medical Faculty, Lithuanian University of Health Sciences, Kaunas, Lithuania,*Correspondence: Lina Jankauskaite
| | - Mantas Malinauskas
- Institute of Physiology and Pharmacology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ausra Snipaitiene
- Department of Pediatrics, Medical Faculty, Lithuanian University of Health Sciences, Kaunas, Lithuania
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Yasmin F, Sahito AM, Mir SL, Khatri G, Shaikh S, Gul A, Hassan SA, Koritala T, Surani S. Electrical neuromodulation therapy for inflammatory bowel disease. World J Gastrointest Pathophysiol 2022; 13:128-142. [PMID: 36187600 PMCID: PMC9516456 DOI: 10.4291/wjgp.v13.i5.128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/19/2022] [Accepted: 07/18/2022] [Indexed: 02/08/2023] Open
Abstract
Inflammatory bowel disease (IBD) is an inflammatory disease of the gastrointestinal (GI) tract. It has financial and quality of life impact on patients. Although there has been a significant advancement in treatments, a considerable number of patients do not respond to it or have severe side effects. Therapeutic approaches such as electrical neuromodulation are being investigated to provide alternate options. Although bioelectric neuromodulation technology has evolved significantly in the last decade, sacral nerve stimulation (SNS) for fecal incontinence remains the only neuromodulation protocol commonly utilized use for GI disease. For IBD treatment, several electrical neuromodulation techniques have been studied, such as vagus NS, SNS, and tibial NS. Several animal and clinical experiments were conducted to study the effectiveness, with encouraging results. The precise underlying mechanisms of action for electrical neuromodulation are unclear, but this modality appears to be promising. Randomized control trials are required to investigate the efficacy of intrinsic processes. In this review, we will discuss the electrical modulation therapy for the IBD and the data pertaining to it.
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Affiliation(s)
- Farah Yasmin
- Department of Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Abdul Moiz Sahito
- Department of Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Syeda Lamiya Mir
- Department of Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Govinda Khatri
- Department of Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Somina Shaikh
- Department of Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan
| | - Ambresha Gul
- Department of Medicine, People’s University of Medical and Health Sciences, Nawabshah 67480, Pakistan
| | - Syed Adeel Hassan
- Department of Medicine, University of Louisville, Louiseville, KY 40292, United States
| | - Thoyaja Koritala
- Department of Medicine, Mayo Clinic, Rochester, NY 55902, United States
| | - Salim Surani
- Department of Medicine, Texas A&M University, College Station, TX 77843, United States
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55902, United States
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Kooijman S, Meurs I, van der Stoep M, Habets KL, Lammers B, Berbée JFP, Havekes LM, van Eck M, Romijn JA, Korporaal SJA, Rensen PCN. Hematopoietic α7 nicotinic acetylcholine receptor deficiency increases inflammation and platelet activation status, but does not aggravate atherosclerosis. J Thromb Haemost 2015; 13:126-35. [PMID: 25345495 DOI: 10.1111/jth.12765] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 10/12/2014] [Indexed: 12/24/2022]
Abstract
BACKGROUND The autonomic nervous system attenuates inflammation through activation of the α7 nicotinic acetylcholine receptor (α7nAChR), a pathway termed the cholinergic anti-inflammatory reflex. Interestingly, α7nAChR is expressed on immune cells and platelets, both of which play a crucial role in the development of atherosclerosis. OBJECTIVE To investigate the role of hematopoietic α7nAChR in inflammation and platelet function in atherosclerotic ldlr(-/-) mice and to identify its consequences for atherosclerotic lesion development. METHODS Bone marrow from α7nAChR(-/-) mice or wild-type littermates was transplanted into irradiated ldlr(-/-) mice. After a recovery period of 8 weeks, the mice were fed an atherogenic Western-type diet for 7 weeks. RESULTS Hematopoietic α7nAChR deficiency clearly increased the number of leukocytes in the peritoneum (2.6-fold, P < 0.001), blood (2.9-fold; P < 0.01), mesenteric lymph nodes (2.0-fold; P < 0.001) and spleen (2.2-fold; P < 0.01), indicative of an increased inflammatory status. Additionally, expression of inflammatory mediators was increased in peritoneal leukocytes (TNFα, 1.6-fold, P < 0.01; CRP, 1.8-fold, P < 0.01) as well as in the spleen (TNFα, 1.6-fold, P < 0.01). The lack of α7nAChR on platelets from these mice increased the expression of active integrin αIIb β3 upon stimulation by ADP (1.9-fold, P < 0.01), indicating increased activation status, while incubation of human platelets with an α7nAChR agonist decreased aggregation (-35%, P < 0.05). Despite the large effects of hematopoietic α7nAChR deficiency on inflammatory status and platelet function, it did not affect atherosclerosis development or composition of lesions. CONCLUSIONS Hematopoietic α7nAChR is important for attenuation of inflammatory responses and maintaining normal platelet reactivity, but loss of hematopoietic α7nAChR does not aggravate development of atherosclerosis.
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Affiliation(s)
- S Kooijman
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, the Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
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Modeling the binding mechanism of Alzheimer's Aβ1-42 to nicotinic acetylcholine receptors based on similarity with snake α-neurotoxins. Neurotoxicology 2012; 34:236-42. [PMID: 23022323 DOI: 10.1016/j.neuro.2012.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/14/2012] [Accepted: 09/14/2012] [Indexed: 11/21/2022]
Abstract
For over a decade, it has been known that amyloid β (Aβ) peptides of Alzheimer's disease bind to the nicotinic α7 acetylcholine receptor (AChR) with picomolar affinity, and that snake α-neurotoxins competitively inhibit this binding. Here we propose a model of the binding mechanism of Aβ peptides to α7-AChR at atomic level. The binding mechanism is based on sequence and structure similarities of Aβ residues with functional residues of snake α-neurotoxins (ATX) in complex with AChR. The binding mechanism involves residue (Aβ)K28 (similar to (ATX)R32) which forms cation/π interactions in the acetylcholine binding site, and residues (Aβ)G29-(Aβ)I32 [GAII] (similar to (ATX)G33-(ATX)I36 [GTII]) which form an intermolecular β-sheet with residues (α7)F189-(α7)E191 of AChR. Through these interactions, we propose that the AChR serves as a chaperone for Aβ conformational changes from α- to β-hairpin. The interactions which block channel opening provide fundamental insight into Aβ neurotoxicity and cognition impairment, that could contribute to pathogenic processes in Alzheimer's disease, thus paving the way for structure based therapies.
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Albuquerque EX, Pereira EFR, Alkondon M, Rogers SW. Mammalian nicotinic acetylcholine receptors: from structure to function. Physiol Rev 2009; 89:73-120. [PMID: 19126755 PMCID: PMC2713585 DOI: 10.1152/physrev.00015.2008] [Citation(s) in RCA: 1227] [Impact Index Per Article: 81.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The classical studies of nicotine by Langley at the turn of the 20th century introduced the concept of a "receptive substance," from which the idea of a "receptor" came to light. Subsequent studies aided by the Torpedo electric organ, a rich source of muscle-type nicotinic receptors (nAChRs), and the discovery of alpha-bungarotoxin, a snake toxin that binds pseudo-irreversibly to the muscle nAChR, resulted in the muscle nAChR being the best characterized ligand-gated ion channel hitherto. With the advancement of functional and genetic studies in the late 1980s, the existence of nAChRs in the mammalian brain was confirmed and the realization that the numerous nAChR subtypes contribute to the psychoactive properties of nicotine and other drugs of abuse and to the neuropathology of various diseases, including Alzheimer's, Parkinson's, and schizophrenia, has since emerged. This review provides a comprehensive overview of these findings and the more recent revelations of the impact that the rich diversity in function and expression of this receptor family has on neuronal and nonneuronal cells throughout the body. Despite these numerous developments, our understanding of the contributions of specific neuronal nAChR subtypes to the many facets of physiology throughout the body remains in its infancy.
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Affiliation(s)
- Edson X Albuquerque
- Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, Baltimore, MD, USA
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Kwon JY, Kim YH, Kim SH, Kang MH, Maeng YS, Lee KY, Park YW. Difference in the expression of alpha 7 nicotinic receptors in the placenta in normal versus severe preeclampsia pregnancies. Eur J Obstet Gynecol Reprod Biol 2006; 132:35-9. [PMID: 16837119 DOI: 10.1016/j.ejogrb.2006.05.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 04/16/2006] [Accepted: 05/26/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The prevalence of preeclampsia is low in smokers, suggesting a possible role of nicotinic receptor in the pathophysiology of the disease. Alpha 7 nicotinic acetylcholine receptor (alpha7 nAChR) was recently found in non-neuronal tissue with various mediating functions. Therefore, we investigated the difference in the placental expression of the alpha7 nAChR in normal versus severe preeclampsia placentas. STUDY DESIGN Central portions of placenta were obtained from 9 severe preeclampsia women and 11 gestational-age-matched normal pregnant women delivered between the gestational ages of 33 and 40 weeks following elective or emergency cesarean section. RT-PCR, western blotting, and immunohistochemical staining were performed to evaluate the alpha7 nAChR expression difference. RESULTS In all the placentas, the alpha7 nAChR was expressed in endothelial cells, vascular smooth muscle cells, and stromal cells, but not in trophoblasts. The vascular staining was more intense in the severe preeclampsia placenta (p=0.02). Although the gene expression did not differ between the two groups, protein expression was greater in 7 of 9 placenta samples from the severe preeclampsia group. CONCLUSION Placental expression of alpha7 nAChR differs between normal and severe preeclampsia placentas, suggesting that it may be involved in the pathogenesis of preeclampsia.
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Affiliation(s)
- Ja-Young Kwon
- Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynecology, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemoon-gu, Seoul 120-752, South Korea
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Chao C, Ives KL, Goluszko E, Kolokoltsov AA, Davey RA, Townsend CM, Hellmich MR. Src Regulates Constitutive Internalization and Rapid Resensitization of a Cholecystokinin 2 Receptor Splice Variant. J Biol Chem 2005; 280:33368-73. [PMID: 16079138 DOI: 10.1074/jbc.m506337200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The third intracellular loop domain of G protein-coupled receptors regulates their desensitization, internalization, and resensitization. Colorectal and pancreatic cancers, but not the nonmalignant tissue, express a splice variant of the cholecystokinin 2 receptor (CCK2R) called CCK(2i4sv)R that, because of intron 4 retention, contains an additional 69 amino acids within its third intracellular loop domain. This structural alteration is associated with agonist-independent activation of Src kinase (Olszewska-Pazdrak, B., Townsend, C. M., Jr., and Hellmich, M. R. (2004) J. Biol. Chem. 279, 40400-40404). The purpose of the study was to determine the roles of intron 4 retention and Src kinase on CCK(2i4sv)R desensitization, internalization, and resensitization. Gastrin1-17 (G17) binds to both CCK2R and CCK(2i4sv)R and induces intracellular Ca2+ ([Ca2+]i) increases. Agonist-induced increases in [Ca2+]i were used to assess receptor activity. Src kinase activity was inhibited by transducing cells with a retrovirus containing a dominant-negative mutant Src (A430V). The subcellular location of enhanced green fluorescent protein-tagged receptors was monitored using laser scanning confocal microscopy. Both receptor variants desensitized at the same rate; however, CCK(2i4sv)R resensitized five times faster than CCK2R. Without agonist, 80% of CCK(2i4sv)R is located in an intracellular compartment. In contrast, 80% of CCK2R was located on the plasma membrane. Treatment with inverse agonist (YM022) or expression of dominant-negative Src blocked the constitutive internalization of CCK(2i4sv)R, resulting in its accumulation on the plasma membrane. Expression of dominant-negative Src slowed the rate of CCK(2i4sv)R resensitization. Inhibition of Src did not affect G17-induced internalization of either receptor variant. Constitutive internalization of CCK(2i4sv)R increases its rate of resensitization by creating an intracellular pool of receptors that can rapidly recycle back to the plasma membrane.
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Affiliation(s)
- Celia Chao
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas 77555, USA
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8
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Abstract
Desensitization is an intriguing characteristic of ligand-gated channels, whereby a decrease or loss of biological response occurs following prolonged or repetitive stimulation. Nicotinic acetylcholine receptors (nAChRs), as a member of transmitter gated ion channels family, also can be desensitized by continuous or repeated exposure to agonist. Desensitization of nicotinic receptors can occur as a result of extended nicotine exposure during smoking or prolonged acetylcholine when treatment of Alzheimer's disease (AD) with cholinesterase inhibitors, or anticholinesterase agent poisoning. Studies from our lab have shown that nAChRs desensitization is not a nonfunctional state and we proposed that desensitized nAChRs could increase sensitivity of brain muscarinic receptor to its agonists. Here, we will review the regulation of nicotinic receptor desensitization and discuss the important biological function of desensitized nicotinic receptors in light of our previous studies. These studies provide the critical information for understanding the importance of nicotinic receptors desensitization in both normal physiological processing and in various disease states.
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Affiliation(s)
- Hai Wang
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China.
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Pavlov VA, Wang H, Czura CJ, Friedman SG, Tracey KJ. The Cholinergic Anti-inflammatory Pathway: A Missing Link in Neuroimmunomodulation. Mol Med 2003. [DOI: 10.1007/bf03402177] [Citation(s) in RCA: 434] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Löscher W, Potschka H, Wlaź P, Danysz W, Parsons CG. Are neuronal nicotinic receptors a target for antiepileptic drug development? Studies in different seizure models in mice and rats. Eur J Pharmacol 2003; 466:99-111. [PMID: 12679146 DOI: 10.1016/s0014-2999(03)01542-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Altered function of neuronal nicotinic acetylcholine receptors in the brain has recently been associated with an idiopathic form of partial epilepsy, suggesting that functional alterations of these receptors can be involved in the processes leading to epileptic seizures. Thus, nicotinic acetylcholine receptors may form a novel target for antiepileptic drug development. In the present study, various nicotinic acetylcholine receptor antagonists, including novel amino-alkyl-cyclohexane derivatives, were evaluated in two animal models, namely the maximal electroshock seizure test in mice and amygdala-kindling in rats. For comparison with these standard models of generalized and partial seizures, the effects against nicotine-induced seizures were examined. Because some of the agents tested showed an overlap between channel blocking at nicotinic acetylcholine receptors and NMDA receptors, the potency at these receptors was assessed by using patch clamp in a hippocampal cell preparation. Preferential nicotinic acetylcholine receptor antagonists were potent anticonvulsants in the maximal electroshock seizure test and against nicotine-induced seizures. The anticonvulsant potency in the maximal electroshock seizure test was decreased by administration of a subconvulsant dose of nicotine. Such a potency shift was also seen with selective NMDA receptor antagonists, which were also efficacious anticonvulsants against both maximal electroshock seizures and nicotine-induced seizures. Experiments with agents combining nicotinic acetylcholine receptor and NMDA receptor antagonistic effects suggested that both mechanisms contributed to the anticonvulsant effect of the respective agents in the maximal electroshock seizure test. This was not found in kindled rats, in which nicotinic acetylcholine receptor antagonists exerted less robust effects. In conclusion, it may be suggested that nicotinic acetylcholine receptor antagonism might be a valuable therapeutic approach to treat generalized epileptic seizures but rather not complex partial seizures.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, School of Veterinary Medicine, Bünteweg 17, 30559, Hannover, Germany.
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Lucas-Meunier E, Fossier P, Baux G, Amar M. Cholinergic modulation of the cortical neuronal network. Pflugers Arch 2003; 446:17-29. [PMID: 12690458 DOI: 10.1007/s00424-002-0999-2] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2002] [Indexed: 01/15/2023]
Abstract
Acetylcholine (ACh) is an important neurotransmitter of the CNS that binds both nicotinic and muscarinic receptors to exert its action. However, the mechanisms underlying the effects of cholinergic receptors have still not been completely elucidated. Central cholinergic neurons, mainly located in basal forebrain, send their projections to different structures including the cortex. The cortical innervation is diffuse and roughly topographic, which has prompted some authors to suspect a modulating role of ACh on the activity of the cortical network rather than a direct synaptic role. The cholinergic system is implicated in functional, behavioural and pathological states including cognitive function, nicotine addiction, Alzheimer's disease, Tourette's syndrome, epilepsies and schizophrenia. As these processes depend on the activation of glutamatergic and GABAergic systems, the cholinergic terminals must exert their effects via the modulation of excitatory and/or inhibitory neurotransmission. However, the understanding of cholinergic modulation is complex because it is the result of a mixture of positive and negative modulation, implying that there are various types, or even subtypes, of cholinergic receptors. In this review, we summarize the current knowledge on central cholinergic systems (projections and receptors) and then aim to focus on the implications for ACh in the modulation of cortical neuronal activity.
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Affiliation(s)
- E Lucas-Meunier
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, INAF-CNRS, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France.
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Wang H, Yu M, Ochani M, Amella CA, Tanovic M, Susarla S, Li JH, Wang H, Yang H, Ulloa L, Al-Abed Y, Czura CJ, Tracey KJ. Nicotinic acetylcholine receptor alpha7 subunit is an essential regulator of inflammation. Nature 2003; 421:384-8. [PMID: 12508119 DOI: 10.1038/nature01339] [Citation(s) in RCA: 2359] [Impact Index Per Article: 112.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2002] [Accepted: 12/02/2002] [Indexed: 02/06/2023]
Abstract
Excessive inflammation and tumour-necrosis factor (TNF) synthesis cause morbidity and mortality in diverse human diseases including endotoxaemia, sepsis, rheumatoid arthritis and inflammatory bowel disease. Highly conserved, endogenous mechanisms normally regulate the magnitude of innate immune responses and prevent excessive inflammation. The nervous system, through the vagus nerve, can inhibit significantly and rapidly the release of macrophage TNF, and attenuate systemic inflammatory responses. This physiological mechanism, termed the 'cholinergic anti-inflammatory pathway' has major implications in immunology and in therapeutics; however, the identity of the essential macrophage acetylcholine-mediated (cholinergic) receptor that responds to vagus nerve signals was previously unknown. Here we report that the nicotinic acetylcholine receptor alpha7 subunit is required for acetylcholine inhibition of macrophage TNF release. Electrical stimulation of the vagus nerve inhibits TNF synthesis in wild-type mice, but fails to inhibit TNF synthesis in alpha7-deficient mice. Thus, the nicotinic acetylcholine receptor alpha7 subunit is essential for inhibiting cytokine synthesis by the cholinergic anti-inflammatory pathway.
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Affiliation(s)
- Hong Wang
- Laboratory of Biomedical Science, North Shore Long Island Jewish Research Institute, 350 Community Drive, Manhasset, New York 11030, USA
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Hennings EC, Kiss JP, De Oliveira K, Toth PT, Vizi ES. Nicotinic acetylcholine receptor antagonistic activity of monoamine uptake blockers in rat hippocampal slices. J Neurochem 1999; 73:1043-50. [PMID: 10461893 DOI: 10.1046/j.1471-4159.1999.0731043.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of our study was to investigate the effect of different monoamine uptake blockers on the nicotine-evoked release of [3H]noradrenaline ([3H]NA) from rat hippocampal slices. We found that desipramine (DMI), nisoxetine, cocaine, citalopram, and nomifensine inhibit the nicotine-evoked release of [3H]NA with an IC50 of 0.36, 0.59, 0.81, 0.93, and 1.84 microM, respectively. These IC50 values showed no correlation with the inhibitory effect (Ki) of monoamine uptake blockers on the neuronal NA transporter (r = 0.17, slope = 0.02), indicating that the NA uptake system is not involved in the process. In whole-cell patch clamp experiments neither drug blocked Na+ currents at 1 microM in sympathetic neurons from rat superior cervical ganglia, and only DMI produced a pronounced inhibition (52% decrease) at 10 microM. Comparison of the effect of DMI and tetrodotoxin (TTX) on the electrical stimulation- and nicotine-evoked release of [3H]NA showed that DMI, in contrast to TTX, inhibits only the nicotine-induced response, indicating that the target of DMI is not the Na+ channel. Our data suggest that monoamine uptake blockers with different chemical structure and selectivity are able to inhibit the nicotinic acetylcholine receptors in the CNS. Because these compounds are widely used in the therapy of depressed patients, our findings may have great importance in the evaluation of their clinical effects.
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Affiliation(s)
- E C Hennings
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest
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