Joseph, Jason P2; Mecca, Adam P2; Regenhardt, Robert W2; Bennion, Douglas M2; Rodríguez, Vermali2; Desland, Fiona2; Patel, Neal A2; Pioquinto, David J2; Unger, Thomas3; Katovich, Michael J4; Steckelings, Ulrike Muscha6; Sumners, Colin5
1 Kardiovaskulær og Renal Forskning, Department of Molecular Medicine, Det Sundhedsvidenskabelige Fakultet, SDU2 Department of Physiology and Functional Genomics & McKnight Brain Institute, University of Florida, Gainesville, Florida, USA.3 School for Cardiovascular Diseases, Maastricht University, Netherlands.4 Department of Pharmacodynamics, University of Florida, Gainesville, Florida, USA.5 Department of Physiology and Functional Genomics & McKnight Brain Institute, University of Florida, Gainesville, Florida, USA. Electronic address: email@example.com Kardiovaskulær og Renal Forskning, Department of Molecular Medicine, Det Sundhedsvidenskabelige Fakultet, SDU
Evidence indicates that angiotensin II type 2 receptors (AT2R) exert cerebroprotective actions during stroke. A selective non-peptide AT2R agonist, Compound 21 (C21), has been shown to exert beneficial effects in models of cardiac and renal disease, as well as hemorrhagic stroke. Here, we hypothesize that C21 may exert beneficial effects against cerebral damage and neurological deficits produced by ischemic stroke. We determined the effects of central and peripheral administration of C21 on the cerebral damage and neurological deficits in rats elicited by endothelin-1 induced middle cerebral artery occlusion (MCAO), a model of cerebral ischemia. Rats infused centrally (intracerebroventricular) with C21 before endothelin-1 induced MCAO exhibited significant reductions in cerebral infarct size and the neurological deficits produced by cerebral ischemia. Similar cerebroprotection was obtained in rats injected systemically (intraperitoneal) with C21 either before or after endothelin-1 induced MCAO. The protective effects of C21 were reversed by central administration of an AT2R inhibitor, PD123319. While C21 did not alter cerebral blood flow at the doses used here, peripheral post-stroke administration of this agent significantly attenuated the MCAO-induced increases in inducible nitric oxide synthase, chemokine (C-C) motif ligand 2 and C-C chemokine receptor type 2 mRNAs in the cerebral cortex, indicating that the cerebroprotective action is associated with an anti-inflammatory effect. These results strengthen the view that AT2R agonists may have potential therapeutic value in ischemic stroke, and provide the first evidence of cerebroprotection induced by systemic post stroke administration of a selective AT2R agonist.