title: Microvascular responses to aldosterone in hamster cheek pouch microcirculation.
abstract: The aim of the present study was to assess the in vivo effects of aldosterone topically applied on the hamster cheek pouch microcirculation under baseline conditions or during ischemia-reperfusion. Male Syrian hamsters were anesthetized, tracheotomized and intubated. They were studied under baseline conditions or submitted to ischemia-reperfusion. Cheek pouch microvessels were visualized by fluorescence microscopy. Microvascular parameters were determined by computerized methods. Under baseline conditions, aldosterone (0.2, 0.5, 2.4 μM/L/2 min) induced dose-dependent constriction of all arterioles within 2.0 ± 0.5 min of administration. Diameter reduction was in the same range in smaller arterioles: A3 ones constricted by 24 ± 3% of baseline (at the highest dose). Aldosterone applied prior to ischemia and at reperfusion caused arteriolar constriction, marked microvascular permeability (0.66 ± 0.03 Normalized Grey Level), reduction in perfused capillary (-70 ± 4% of baseline) and leukocyte adhesion. All changes were statistically significant compared with ischemic animals. Potassium canrenoate (mineralcorticoid receptor inhibitor) prior to aldosterone did not abolish the aldosterone-induced effects, while valsartan (angiotensin II AT1 receptor inhibitor) prior to aldosterone ameliorated microvascular ischemia-reperfusion injury. In conclusion, aldosterone determined dose-dependent arteriolar constriction likely by angiotensin II type-1 receptor activation (non-genomic mechanism) worsening the effects of ischemia-reperfusion on capillary perfusion, while protecting from free radical formation.
authors.affiliation: Department of Neuroscience, Federico II University Medical School, Naples, Italy. d.lapi@dfb.unipi.it
authors.forename: Dominga
authors.initials: D
authors.lastname: Lapi
authors.forename: Michele
authors.initials: M
authors.lastname: Emdin
authors.forename: Teresa
authors.initials: T
authors.lastname: Mastantuono
authors.forename: Daniela
authors.initials: D
authors.lastname: Sapio
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: Santillo
authors.forename: Antonio
authors.initials: A
authors.lastname: Colantuoni
mesh_terms: D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D002448:Cell Adhesion; D002610:Cheek / Q000098:blood supply; D006224:Cricetinae; D004195:Disease Models, Animal; D007511:Ischemia / Q000188:drug therapy / Q000473:pathology; D008297:Male; D008647:Mesocricetus; D008833:Microcirculation / Q000187:drug effects*; D015424:Reperfusion; D016896:Treatment Outcome
chemical_list: D000450:Aldosterone