title: Nicotinic receptor activation by epibatidine induces heme oxygenase-1 and protects chromaffin cells against oxidative stress.
abstract: Activation of neuronal nicotinic acetylcholine receptors (nAChR) provides neuroprotection against different toxic stimuli that often lead to overproduction of reactive oxygen species (ROS) and cell death. ROS production has been related with disease progression in several neurodegenerative pathologies such as Alzheimer's or Parkinson's diseases. In this context, we investigated here if the exposure of bovine chromaffin cells to the potent nAChR agonist epibatidine protected against rotenone (30 micromol/L) plus oligomycin (10 micromol/L) (rot/oligo) toxicity, an in vitro model of mitochondrial ROS production. Epibatidine induced a concentration- and time-dependent protection, which was maximal at 3 mumol/L after 24 h. Pre-incubation with dantrolene (100 micromol/L) (a blocker of the ryanodine receptor channel), chelerythrine (1 micromol/L) (a protein kinase C inhibitor), or PD98059 (50 micromol/L) (a MEK inhibitor), aborted epibatidine-elicited cytoprotection. Mitochondrial depolarization, ROS, and caspase 3 active produced by rot/oligo were also prevented by epibatidine. Epibatidine doubled the amount of heme oxygenase-1 (HO-1), a critical cell defence enzyme against oxidative stress. Furthermore, the HO-1 inhibitor Sn(IV) protoporphyrin IX dichloride reversed the epibatidine protecting effects and HO-1 inducer Co (III) protoporphyrin IX dichloride exhibited neuroprotective effects by itself. The results of this study point to HO-1 as the cytoprotective target of nAChR activation through the following pathway: endoplasmic reticulum Ca(2+)-induced Ca(2+)-release activates the protein kinase C/extracellular regulated kinase/HO-1 axis to mitigate mitochondrial depolarization and ROS production. This study provides a mechanistic insight on how nAChR activation translates into an antioxidant and antiapoptotic signal through up-regulation of HO-1.
authors.affiliation: Intituto Teofilo Hernando, Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, SpainDepartamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, SpainServicio de Farmacología Clínica and Instituto Universitario de Investigación Gerontológica y metabólica, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Egea
authors.affiliation: Intituto Teofilo Hernando, Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, SpainDepartamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, SpainServicio de Farmacología Clínica and Instituto Universitario de Investigación Gerontológica y metabólica, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: Angelo O
authors.initials: AO
authors.lastname: Rosa
authors.affiliation: Intituto Teofilo Hernando, Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, SpainDepartamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, SpainServicio de Farmacología Clínica and Instituto Universitario de Investigación Gerontológica y metabólica, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cuadrado
authors.affiliation: Intituto Teofilo Hernando, Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, SpainDepartamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, SpainServicio de Farmacología Clínica and Instituto Universitario de Investigación Gerontológica y metabólica, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: Antonio G
authors.initials: AG
authors.lastname: García
authors.affiliation: Intituto Teofilo Hernando, Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, SpainDepartamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, SpainServicio de Farmacología Clínica and Instituto Universitario de Investigación Gerontológica y metabólica, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: Manuela G
authors.initials: MG
authors.lastname: López
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects* / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000187:drug effects / Q000378:metabolism; D018722:Nicotinic Agonists / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D004791:Enzyme Inhibitors; D018722:Nicotinic Agonists; D011725:Pyridines; D017382:Reactive Oxygen Species; D011978:Receptors, Nicotinic; D014475:Uncoupling Agents; D051547:Heme Oxygenase-1; D011493:Protein Kinase C; D048052:Mitogen-Activated Protein Kinase 3; C082748:epibatidine