title: Adrenomedullin and angiotensin II signaling pathways involved in the effects on cerebellar antioxidant enzymes activity.
abstract: Human adrenomedullin (AM) is a 52-amino acid peptide involved in cardiovascular control. AM has two specific receptors formed by the calcitonin-receptor-like receptor (CRLR) and receptor activity-modifying protein (RAMP) 2 or 3, known as AM1 and AM2 receptors, respectively. In addition, AM has appreciable affinity for the calcitonin gene-1 related peptide receptor (CGRP1), composed of CRLR/RAMP1. In brain, AM and their receptors are expressed in several localized areas, including the cerebellum. AM has been reported as an antioxidant. Little is known about the role of AM in the regulation of cerebellar reactive oxygen species (ROS) metabolism. We assessed the effect of AM on three antioxidant enzymes activity: catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) and on thiobarbituric acid reactive substances (TBARS) production in rat cerebellar vermis, as well the receptor subtypes involved in AM actions. Additionally, we evaluated the role of angiotensin II (ANG II), protein kinase A (PKA) activity, and protein kinase C/nicotinamide adenine dinucleotide phosphate oxidase (PKC/NAD(P)H) (oxidase) pathway. Sprague-Dawley rats were sacrificed by decapitation and cerebellar vermis was microdissected under stereomicroscopic control. CAT, GPx, SOD activity and TBARS production was determined spectrophotometrically. Our findings demonstrated that in cerebellar vermis, AM decreased and ANG II increased CAT, GPx and SOD activity and TBARS production. Likewise, AM antagonized ANG II-induced increase antioxidant enzyme activity. AM(22-50) and CGRP(8-37) blunted AM-induced decrease of antioxidant enzymes activity and TBARS production indicating that these actions are mediated through AM and CGRP1receptors. Further, PKA inhibitor (PKAi) blunted AM action and apocynin and chelerythrine reverted ANG II action, suggesting that AM antioxidant action is mediated through stimulation of PKA activity, while ANG II-induced stimulation through PKC/NAD(P)H oxidase pathway. Our results support the role of AM in the regulation of cerebellar antioxidant enzymes activity and suggest a physiological role for AM in cerebellum.
authors.affiliation: School of Pharmacy, Laboratory of Neuropeptides, Universidad Central de Venezuela, Caracas, Venezuela; School of Bioanalysis, Laboratory of Investigation and Postgraduate of School of Bioanalysis (LIPEB), Department of Health Sciences, Universidad de Carabobo, Carabobo, Venezuela.
authors.forename: Figueira
authors.initials: F
authors.lastname: Leticia
authors.affiliation: School of Pharmacy, Laboratory of Neuropeptides, Universidad Central de Venezuela, Caracas, Venezuela. Electronic address: astern88@gmail.com.
authors.forename: Israel
authors.initials: I
authors.lastname: Anita
mesh_terms: D053607:Adrenomedullin / Q000378:metabolism*; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D065814:Cerebellar Vermis / Q000187:drug effects / Q000201:enzymology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D008297:Male; D009249:NADP / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D018015:Receptors, Calcitonin Gene-Related Peptide / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D018015:Receptors, Calcitonin Gene-Related Peptide; D017392:Thiobarbituric Acid Reactive Substances; D000804:Angiotensin II; D053607:Adrenomedullin; D009249:NADP; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C
keywords: Adrenomedullin; Angiotensin II; Apocynin; Cerebellum; Chelerythrine