title: Short-term angiotensin converting enzyme inhibition reduces basal tone and dilator reactivity in skeletal muscle arterioles.
abstract: Alterations in resting tone, maximum diameter, and dilator reactivity to acetylcholine (ACH) and sodium nitroprusside (SNP) were assessed in cremaster muscle microvessels of Sprague-Dawley rats receiving angiotensin converting enzyme (ACE) inhibition with captopril for 4 days and in untreated time-control rats. The transilluminated in situ cremaster muscle was superfused with physiologic salt solution (PSS) and viewed via television microscopy; arteriolar diameter was measured using a videomicrometer. Before agonist challenge, resting arteriolar diameter was significantly increased in captopril-treated rats. Although maximum arteriolar diameter (determined during superfusion of the cremaster muscle with Ca2+-free PSS containing 10(-4) mol/L adenosine) was not altered with ACE inhibition, the maximum possible arteriolar dilation was reduced in captopril-treated rats. Captopril administration reduced both ACH- and SNP-induced dilation of cremasteric arterioles compared with responses in control rats, although this was partially a function of the reduced capacity for dilation, primarily to SNP. These observations indicate that short-term ACE inhibition reduces both resting tone and agonist-induced dilator responses of skeletal muscle arterioles.
authors.affiliation: Department of Physiology, Medical College of Wisconsin, Milwaukee 53226, USA. jfrisbee@mcw.edu
authors.forename: J C
authors.initials: JC
authors.lastname: Frisbee
authors.forename: J H
authors.initials: JH
authors.lastname: Lombard
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000201:enzymology; D001794:Blood Pressure; D001835:Body Weight; D002216:Captopril / Q000494:pharmacology*; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D014665:Vasodilator Agents; D009599:Nitroprusside; D002216:Captopril; D000109:Acetylcholine