title: Effects of antihypertensive therapy on mechanics of cerebral arterioles in rats.
abstract: The purpose of this study was to examine effects of antihypertensive treatment on structure and mechanics of cerebral arterioles and the incidence of stroke in stroke-prone spontaneously hypertensive rats (SHRSP). Treatment of hypertension was begun at 3 months of age with cilazapril (45 mg/kg/day), an angiotensin converting enzyme (ACE) inhibitor, or with hydralazine (18 mg/kg/day). Cilazapril and hydralazine reduced systolic arterial pressure (from 195 +/- 8 to 125 +/- 5 and 148 +/- 3 mm Hg, respectively [mean +/- SEM]; p less than 0.05). To examine structure and mechanics of cerebral arterioles, we measured pressure (servonull), external diameter, and cross-sectional area of the vessel wall (histologically) in pial arterioles of normotensive Wistar-Kyoto (WKY) rats and SHRSP that were untreated or that were treated for 3 months with cilazapril or with hydralazine. Arterioles were maximally dilated with EDTA. In WKY rats, cilazapril and hydralazine did not alter pial arteriolar pressure, external diameter, or cross-sectional area of the vessel wall. In SHRSP, both cilazapril and hydralazine reduced cross-sectional area of the vessel wall to levels not significantly different from WKY rats (from 1,911 +/- 155 to 1,244 +/- 101 and 1,388 +/- 59 microns 2, respectively, compared with 1,405 +/- 95 microns 2 for untreated WKY rats). Cilazapril was more effective than hydralazine in reducing pial arteriolar pressure (from 110 +/- 6 to 62 +/- 2 mm Hg with cilazapril versus 79 +/- 5 mm Hg for hydralazine compared with 60 +/- 4 mm Hg for untreated WKY rats). Cilazapril, but not hydralazine, attenuated reductions in external diameter of pial arterioles (from 91 +/- 4 to 100 +/- 4 microns for cilazapril versus 91 +/- 3 microns for hydralazine compared with 107 +/- 3 microns for untreated WKY rats).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: University of Iowa College of Medicine, Department of Pathology, Iowa City 52242.
authors.forename: M A
authors.initials: MA
authors.lastname: Hajdu
authors.forename: D D
authors.initials: DD
authors.lastname: Heistad
authors.forename: G L
authors.initials: GL
authors.lastname: Baumbach
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002536:Cerebral Arteries / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D002561:Cerebrovascular Disorders / Q000517:prevention & control; D017315:Cilazapril; D006830:Hydralazine / Q000494:pharmacology*; D006973:Hypertension / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D006984:Hypertrophy; D008297:Male; D011724:Pyridazines / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D011724:Pyridazines; D017315:Cilazapril; D006830:Hydralazine