title: Selective in vivo antagonism of endothelin receptors in transforming growth factor-beta1 transgenic mice that mimic the vascular pathology of Alzheimer's disease.
abstract: Increased levels of transforming growth factor-beta1 (TGF-beta1) induce a vascular pathology that shares similarities with that seen in Alzheimer's disease, and which possibly contributes to the cognitive decline. In aged transgenic mice that overexpress TGF-beta1 (TGF mice), we previously found reduced dilatory function and selectively impaired endothelin-1 (ET-1)-induced contraction. Here we studied the effects of chronic treatments with selective ETA (ABT-627) or ETB (A-192621) receptor antagonist on cerebrovascular reactivity, cerebral perfusion, or memory performance. The dilatory deficit of TGF mice was not improved by either treatment, but both ET-1 contraction and basal nitric oxide (NO) production were distinctly altered. Although ABT-627 was devoid of any effect in TGF mice, it virtually abolished the ET-1-induced contraction and NO release in wild-type (WT) littermates. In contrast, A-192621 only acted upon TGF mice with full recovery of ET-1 contraction and baseline NO synthesis. TGF mice, treated or not, had no cognitive deficit in the Morris water maze, nor did ABT-627-treated WT controls despite severely impaired vasoreactivity. These findings confirm that ETA receptors primarily mediate the ET-1-induced contraction. Further, they suggest that ETB receptors play a detrimental role in conditions of increased TGF-beta1 and that vascular dysfunction does not inevitably lead to cognitive deficit.
authors.affiliation: Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, QC H3A 2B4, Canada.
authors.forename: Panayiota
authors.initials: P
authors.lastname: Papadopoulos
authors.forename: Brice
authors.initials: B
authors.lastname: Ongali
authors.forename: Edith
authors.initials: E
authors.lastname: Hamel
mesh_terms: D000375:Aging / Q000502:physiology; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D000077868:Atrasentan; D001808:Blood Vessels / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D001921:Brain / Q000098:blood supply* / Q000503:physiopathology; D002536:Cerebral Arteries / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology; D005260:Female; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009569:Nitric Oxide / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology; D014738:Vibrissae / Q000502:physiology
chemical_list: C120508:A 192621; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D011759:Pyrrolidines; D053773:Transforming Growth Factor beta1; D014665:Vasodilator Agents; D019335:Nitroarginine; D009569:Nitric Oxide; D000077868:Atrasentan