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Azizi N, Toma J, Martin M, Khalid MF, Mousavi F, Win PW, Borrello MT, Steele N, Shi J, di Magliano MP, Pin CL. Loss of activating transcription factor 3 prevents KRAS-mediated pancreatic cancer. Oncogene 2021; 40:3118-3135. [PMID: 33864001 PMCID: PMC8173475 DOI: 10.1038/s41388-021-01771-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/04/2021] [Accepted: 03/16/2021] [Indexed: 02/02/2023]
Abstract
The unfolded protein response (UPR) is activated in pancreatic pathologies and suggested as a target for therapeutic intervention. In this study, we examined activating transcription factor 3 (ATF3), a mediator of the UPR that promotes acinar-to-ductal metaplasia (ADM) in response to pancreatic injury. Since ADM is an initial step in the progression to pancreatic ductal adenocarcinoma (PDAC), we hypothesized that ATF3 is required for initiation and progression of PDAC. We generated mice carrying a germline mutation of Atf3 (Atf3-/-) combined with acinar-specific induction of oncogenic KRAS (Ptf1acreERT/+KrasG12D/+). Atf3-/- mice with (termed APK) and without KRASG12D were exposed to cerulein-induced pancreatitis. In response to recurrent pancreatitis, Atf3-/- mice showed decreased ADM and enhanced regeneration based on morphological and biochemical analysis. Similarly, an absence of ATF3 reduced spontaneous pancreatic intraepithelial neoplasia (PanIN) formation and PDAC in Ptf1acreERT/+KrasG12D/+ mice. In response to injury, KRASG12D bypassed the requirement for ATF3 with a dramatic loss in acinar tissue and PanIN formation observed regardless of ATF3 status. Compared to Ptf1acreERT/+KrasG12D/+ mice, APK mice exhibited a significant decrease in pancreatic and total body weight, did not progress through to PDAC, and showed altered pancreatic fibrosis and immune cell infiltration. These findings suggest a complex, multifaceted role for ATF3 in pancreatic cancer pathology.
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Affiliation(s)
- Nawab Azizi
- Children's Health Research Institute, London, ON, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Jelena Toma
- Children's Health Research Institute, London, ON, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
- Department of Oncology, University of Western Ontario, London, ON, Canada
| | - Mickenzie Martin
- Children's Health Research Institute, London, ON, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
- Department of Biology, University of Western Ontario, London, ON, Canada
| | - Muhammad Faran Khalid
- Children's Health Research Institute, London, ON, Canada
- Department of Paediatrics, University of Western Ontario, London, ON, Canada
| | - Fatemeh Mousavi
- Children's Health Research Institute, London, ON, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Phyo Wei Win
- Children's Health Research Institute, London, ON, Canada
- Department of Paediatrics, University of Western Ontario, London, ON, Canada
| | - Maria Teresa Borrello
- Centre for Cancer Research Marseille, INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Marseille, France
| | - Nina Steele
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Jiaqi Shi
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | | | - Christopher L Pin
- Children's Health Research Institute, London, ON, Canada.
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
- Department of Oncology, University of Western Ontario, London, ON, Canada.
- Department of Paediatrics, University of Western Ontario, London, ON, Canada.
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Toma J, Hammond B, Chan V, Peacocke A, Salehi B, Jhingan P, Brooks D, Hébert AA, Marzolini S. Inclusion of People Poststroke in Cardiac Rehabilitation Programs in Canada: A Missed Opportunity for Referral. CJC Open 2020; 2:195-206. [PMID: 32695969 PMCID: PMC7365786 DOI: 10.1016/j.cjco.2020.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 01/29/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Evidence supports establishing a continuum of care from stroke rehabilitation (SR) to cardiac rehabilitation programs (CRPs). It is not known to what extent people poststroke are being integrated. This study aimed to determine the proportion of CRPs that accept referrals poststroke, barriers/facilitators, and eligibility criteria. METHODS A web-based questionnaire was sent to CRPs across Canada. RESULTS Of 160 questionnaires sent, 114 representatives (71%) of 130 CRPs responded. Of respondents, 65% (n = 74) reported accepting people with a diagnosis of stroke and doing so for a median of 11 years, 11 offering stroke-specific classes and an additional 6 planning inclusion. However, 62.5% of CRPs reported that < 11 patients participated in the last calendar year despite 88.5% reporting no limit to the number they could enroll. Among CRPs, 25% accepted only patients with concurrent cardiac diagnoses, living in the community (47.8%), and without severe mobility (70.1%), communication (80.6%), or cognitive (85.1%) deficits. The 2 most influential barriers and facilitators among all CRPs were funding and staffing. The fourth greatest barrier was lack of poststroke referrals, and third to sixth facilitators were SR/CRP collaboration to ensure appropriate referrals (third) and to increase referrals (sixth), toolkits for prescribing resistance (fourth), and aerobic training (fifth). CRP characteristics associated with accepting stroke were a hybrid program model, a medium program size, and having a falls prevention component. CONCLUSIONS Most CRPs accept patients poststroke, but few participate. Therefore, establishing SR/CRP partnerships to increase appropriate referrals, using a toolkit to help operationalize exercise components, and allocating funding/resources to CRPs may significantly increase access to secondary prevention strategies.
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Affiliation(s)
- Jelena Toma
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Brittany Hammond
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Vito Chan
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Alex Peacocke
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Baharak Salehi
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Prateek Jhingan
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Dina Brooks
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
- KITE Research Institute, Toronto Rehab-University Health Network, Toronto, Ontario, Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Ottawa, Ontario, Canada
- McMaster University, Hamilton, Ontario, Canada
| | | | - Susan Marzolini
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
- KITE Research Institute, Toronto Rehab-University Health Network, Toronto, Ontario, Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Ottawa, Ontario, Canada
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Fazio EN, Young CC, Toma J, Levy M, Berger KR, Johnson CL, Mehmood R, Swan P, Chu A, Cregan SP, Dilworth FJ, Howlett CJ, Pin CL. Activating transcription factor 3 promotes loss of the acinar cell phenotype in response to cerulein-induced pancreatitis in mice. Mol Biol Cell 2017; 28:2347-2359. [PMID: 28701342 PMCID: PMC5576899 DOI: 10.1091/mbc.e17-04-0254] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/22/2017] [Accepted: 06/27/2017] [Indexed: 12/20/2022] Open
Abstract
Pancreatitis is a debilitating disease of the exocrine pancreas that, under chronic conditions, is a major susceptibility factor for pancreatic ductal adenocarcinoma (PDAC). Although down-regulation of genes that promote the mature acinar cell fate is required to reduce injury associated with pancreatitis, the factors that promote this repression are unknown. Activating transcription factor 3 (ATF3) is a key mediator of the unfolded protein response, a pathway rapidly activated during pancreatic insult. Using chromatin immunoprecipitation followed by next-generation sequencing, we show that ATF3 is bound to the transcriptional regulatory regions of >30% of differentially expressed genes during the initiation of pancreatitis. Of importance, ATF3-dependent regulation of these genes was observed only upon induction of pancreatitis, with pathways involved in inflammation, acinar cell differentiation, and cell junctions being specifically targeted. Characterizing expression of transcription factors that affect acinar cell differentiation suggested that acinar cells lacking ATF3 maintain a mature cell phenotype during pancreatitis, a finding supported by maintenance of junctional proteins and polarity markers. As a result, Atf3-/- pancreatic tissue displayed increased tissue damage and inflammatory cell infiltration at early time points during injury but, at later time points, showed reduced acinar-to-duct cell metaplasia. Thus our results reveal a critical role for ATF3 as a key regulator of the acinar cell transcriptional response during injury and may provide a link between chronic pancreatitis and PDAC.
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Affiliation(s)
- Elena N Fazio
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Oncology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Claire C Young
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Jelena Toma
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Michael Levy
- Children's Health Research Institute, London, ON N6C 2V5, Canada
| | - Kurt R Berger
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Charis L Johnson
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Rashid Mehmood
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Patrick Swan
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Alphonse Chu
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Sean P Cregan
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
- Robarts Research Institute, University of Western Ontario, London, ON N6A 5B7, Canada
| | - F Jeffrey Dilworth
- Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Christopher J Howlett
- Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Christopher L Pin
- Children's Health Research Institute, London, ON N6C 2V5, Canada
- Department of Paediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Oncology, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
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Pang DKT, Nong Z, Sutherland BG, Sawyez CG, Robson DL, Toma J, Pickering JG, Borradaile NM. Niacin promotes revascularization and recovery of limb function in diet-induced obese mice with peripheral ischemia. Pharmacol Res Perspect 2016; 4:e00233. [PMID: 27433343 PMCID: PMC4876143 DOI: 10.1002/prp2.233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/07/2016] [Accepted: 03/11/2016] [Indexed: 12/20/2022] Open
Abstract
Niacin can reduce vascular disease risk in individuals with metabolic syndrome, but in light of recent large randomized controlled trials outcomes, its biological actions and clinical utility remain controversial. Niacin can improve endothelial function, vascular inflammation, and vascular regeneration, independent of correcting dyslipidemia, in various lean rodent models of vascular injury. Here, we tested whether niacin could directly improve endothelial cell angiogenic function during combined exposure to excess fatty acids and hypoxia, and whether intervention with niacin during continued feeding of western diet could improve revascularization and functional recovery in obese, hyperlipidemic mice with peripheral ischemia. Treatment with niacin (10 μmol/L) increased human microvascular endothelial cell angiogenic function during exposure to high fatty acids and hypoxia (2% oxygen), as determined by tube formation on Matrigel. To assess revascularization in vivo, we used western diet-induced obese mice with unilateral hind limb femoral artery ligation and excision. Treatment for 14 days postinjury with once daily i.p. injections of a low dose of niacin (50 mg/kg) improved recovery of hind limb use, in association with enhanced revascularization and decreased inflammation of the tibialis anterior muscle. These effects were concomitant with decreased plasma triglycerides, but not increased plasma apoAI. Thus, niacin improves endothelial tube formation under lipotoxic and hypoxic conditions, and moreover, promotes revascularization and functional hind limb recovery following ischemic injury in diet-induced obese mice with hyperlipidemia. These data may have implications for niacin therapy in the treatment of peripheral ischemic vascular disease associated with metabolic syndrome.
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Affiliation(s)
- Dominic K T Pang
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1
| | - Zengxuan Nong
- Robarts Research Institute Western University London Ontario Canada N6A 5C1
| | - Brian G Sutherland
- Robarts Research Institute Western University London Ontario Canada N6A 5C1
| | - Cynthia G Sawyez
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1; Robarts Research Institute Western University London Ontario Canada N6A 5C1; Department of Medicine Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1
| | - Debra L Robson
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1
| | - Jelena Toma
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1
| | - J Geoffrey Pickering
- Robarts Research Institute Western University London Ontario Canada N6A 5C1; Department of Medicine Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1; Department of Biochemistry Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1; Department of Medical Biophysics Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1; London Health Sciences Centre London Ontario Canada N6A 5C1
| | - Nica M Borradaile
- Department of Physiology and Pharmacology Schulich School of Medicine and Dentistry Western University London Ontario Canada N6A 5C1
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Hughes-Large JM, Pang DKT, Robson DL, Chan P, Toma J, Borradaile NM. Niacin receptor activation improves human microvascular endothelial cell angiogenic function during lipotoxicity. Atherosclerosis 2014; 237:696-704. [PMID: 25463108 DOI: 10.1016/j.atherosclerosis.2014.10.090] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/09/2014] [Accepted: 10/21/2014] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Niacin (nicotinic acid) as a monotherapy can reduce vascular disease risk, but its mechanism of action remains controversial, and may not be dependent on systemic lipid modifying effects. Niacin has recently been shown to improve endothelial function and vascular regeneration, independent of correcting dyslipidemia, in rodent models of vascular injury and metabolic disease. As a potential biosynthetic precursor for NAD(+), niacin could elicit these vascular benefits through NAD(+)-dependent, sirtuin (SIRT) mediated responses. Alternatively, niacin may act through its receptor, GPR109A, to promote endothelial function, though endothelial cells are not known to express this receptor. We hypothesized that niacin directly improves endothelial cell function during exposure to lipotoxic conditions and sought to determine the potential mechanism(s) involved. METHODS AND RESULTS Angiogenic function in excess palmitate was assessed by tube formation following treatment of human microvascular endothelial cells (HMVEC) with either a relatively low concentration of niacin (10 μM), or nicotinamide mononucleotide (NMN) (1 μM), a direct NAD(+) precursor. Although both niacin and NMN improved HMVEC tube formation during palmitate overload, only NMN increased cellular NAD(+) and SIRT1 activity. We further observed that HMVEC express GRP109A. Activation of this receptor with either acifran or MK-1903 recapitulated niacin-induced improvements in HMVEC tube formation, while GPR109A siRNA diminished the effect of niacin. CONCLUSION Niacin, at a low concentration, improves HMVEC angiogenic function under lipotoxic conditions, likely independent of NAD(+) biosynthesis and SIRT1 activation, but rather through niacin receptor activation.
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Affiliation(s)
- Jennifer M Hughes-Large
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Dominic K T Pang
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Debra L Robson
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Pak Chan
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Jelena Toma
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Nica M Borradaile
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada.
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Qiang B, Toma J, Fujii H, Osherov A, Nili N, Fefer P, Samuel M, Butany J, Leong-Poi H, Strauss B. 091 Statins prevent expansive remodeling in arterialized vein grafts. Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Chao CC, Sytwu HK, Chen EL, Toma J, McDevitt HO. The role of MHC class II molecules in susceptibility to type I diabetes: identification of peptide epitopes and characterization of the T cell repertoire. Proc Natl Acad Sci U S A 1999; 96:9299-304. [PMID: 10430937 PMCID: PMC17775 DOI: 10.1073/pnas.96.16.9299] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Susceptibility to type I diabetes is linked to class II MHC alleles in both mouse and man. However, the molecular mechanisms by which MHC molecules mediate disease susceptibility are unknown. To analyze how I-A alleles predispose to, or prevent, the development of type I diabetes, we have chosen, as the first step, to investigate the immune response to an important islet cell protein in diabetes-susceptible and diabetes-resistant mice. MHC class II alleles conferring susceptibility and resistance to diabetes select completely different sets of immunogenic epitopes from the beta islet cell autoantigen glutamic acid decarboxylase 65. Peptide-binding studies, analysis of MHC restriction, and immunization with these peptide epitopes indicate that the two amino acid substitutions within the I-A(beta) chain that distinguish a diabetes-susceptibility from a diabetes-resistance allele are sufficient to alter peptide binding and MHC restriction and may also influence antigen presentation and the selection of the T cell repertoire. The data indicate that the molecular mechanisms for class II-mediated selection of immunodominant epitopes are complex and differ for each individual peptide epitope. Further study of the functional characteristics of the response to these epitopes should provide insight into mechanisms of MHC-mediated diabetes susceptibility.
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Affiliation(s)
- C C Chao
- Departments of Microbiology and Immunology, and Medicine, Stanford University Medical Center, Stanford, CA 94305, USA
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Abstract
Intracortical injection of iron ions has been used as a model of posttraumatic epilepsy. Oxidation of lipids in neural membranes by reactive oxygen species, especially hydroxyl radicals (OH), is involved in the mechanisms responsible for iron-induced seizures. We examined the scavenging effects of adenosine (Ado) and 2-chloroadenosine (Cl-Ado) on OH radicals and superoxide (O2.-) using an electron spin resonance (ESR) spectrometer, and the occurrence of epileptic discharges in electrocorticogram (ECoG) induced by FeCl3 injection into the sensorimotor cortex of rats. Though DMPO-O2.- spin adducts generated by the hypoxanthine-xanthine oxidase system were not quenched by Ado or Cl-Ado, 5 mM of each showed a quenching effect on DMPO-OH spin adducts (5.3 x 10(16) spins/ml) generated by the Fenton reagent. In ECoG of rats, spike discharges appeared 15-45 min after FeCl3 injection (500 nmol) into the sensorimotor cortex, and polyspikes and/or ictal patterns were observed 70-90 min after the injection. Cl-Ado (1 mg/kg) or Ado (5 mg/kg) injected intraperitoneally 30 min prior to the FeCl3 injection suppressed or delayed the occurrence of epileptic discharges induced by FeCl3. Cl-Ado and Ado may suppress the occurrence of epileptic discharges by scavenging OH and by their anticonvulsant effect.
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Affiliation(s)
- I Yokoi
- Department of Neuroscience, Okayama University Medical School, Japan
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Yokoi I, Kabuto H, Habu H, Inada K, Toma J, Mori A. Structure-activity relationships of arginine analogues on nitric oxide synthase activity in the rat brain. Neuropharmacology 1994; 33:1261-5. [PMID: 7532812 DOI: 10.1016/0028-3908(94)90025-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nitric oxide (NO) is synthesized by nitric oxide synthase (NOS) from L-arginine (Arg) which has a guanidino group in its molecule. We examined the effect of 23 different Arg analogues on NOS activity in the rat brain. Though homoarginine, epsilon-guanidinocaproic acid and canavanine act as substrates of NOS, production of NO from them was lower than that from Arg. alpha-Guanidinoglutaric acid (2-GGA) and arcaine inhibited NOS activity at levels equal to NG-monomethyl-L-arginine (MeArg), a well known NOS inhibitor. Though almost all previously reported NOS inhibitors were synthesized by substituting the guanidino nitrogen of Arg, the guanidino nitrogens of arcaine and 2-GGA were not substituted. Furthermore, 2-GGA is a known endogenous convulsant in mammals, and arcaine, which was isolated from a marine mollusc, is also a convulsive substance. Hence, 2-GGA and arcaine will be excellent drugs to investigate not only the chemical nature of NOS but also the physiologic function of NO.
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Affiliation(s)
- I Yokoi
- Department of Neuroscience, Okayama University Medical School, Japan
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