title: Reactivity of small intramyocardial arteries from atherosclerotic and non-atherosclerotic human hearts.
abstract: Little is known about how the vascular reactivity of the coronary microcirculation is affected by upstream atherosclerotic disease. We have examined, with a wire myograph, the responses of intramyocardial arteries from hearts in which the epicardial vessels were either free of atherosclerotic lesions (non-diseased group) or were affected by atherosclerosis (diseased group). Vasodilator responses of preconstricted vessels to substance P (84.1 +/- 12.6 compared to 42.0 +/- 19.7%) were less in vessels from the diseased group (p < 0.05). In contrast, the relaxation to bradykinin (70.2 +/- 21.2 compared to 100.6 +/- 7.9%) was increased in vessels from the diseased group (p < 0.05). The dilator responses to acetylcholine, adenosine diphosphate, histamine and sodium nitroprusside showed no significant differences between arteries from each group. 5-Hydroxytryptamine was without any significant vasodilator effect in arteries from either group. Assessment of contractile function revealed that the responses to 5-hydroxytryptamine, acetylcholine, U46619, endothelin-1 and L-N(G)-monomethylarginine in each group were not significantly different. Histamine, noradrenaline and dopamine were without any significant contractile response. These results demonstrate that upstream atherosclerosis does not confer any global impairment of endothelium-dependent vasorelaxant responses or smooth muscle hyperreactivity to vasoconstrictors in the arteries that penetrate the myocardium.
authors.affiliation: Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Harefield Hospital, Middlesex, UK.
authors.forename: A H
authors.initials: AH
authors.lastname: Chester
authors.forename: J A
authors.initials: JA
authors.lastname: Borland
authors.forename: K J
authors.initials: KJ
authors.lastname: Morrison
authors.forename: M
authors.initials: M
authors.lastname: Amrani
authors.forename: S M
authors.initials: SM
authors.lastname: Thom
authors.forename: M H
authors.initials: MH
authors.lastname: Yacoub
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D001161:Arteriosclerosis / Q000473:pathology / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000737:chemistry / Q000473:pathology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000109:Acetylcholine