Abnormal responses to endothelial agonists in Raynaud's phenomenon and scleroderma.
OBJECTIVE
To further specify the site of vascular dysfunction in patients with Raynaud's phenomenon (RP) and scleroderma.


METHODS
Ten patients with RP and scleroderma and 11 healthy control subjects received brachial artery infusions of sodium nitroprusside, an endothelium independent vasodilator, bradykinin, and substance P while bilateral finger blood flow was measured with venous occlusion plethysmography.


RESULTS
Both groups showed vasodilation to sodium nitroprusside. However, in response to the endothelium dependent compounds bradykinin and substance P, the controls showed vasodilation, whereas the patients showed vasoconstriction.


CONCLUSIONS
The vascular defect in RP and scleroderma does not lie at the site of the muscarinic receptor, but possibly in a distal signaling mechanism.
Freedman
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RR
Department of Psychiatry, Wayne State University School of Medicine, Detroit, Michigan, USA. aa2613@wayne.edu
Girgis
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R
Mayes
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MD
D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001920:Bradykinin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D005385:Fingers / Q000098:blood supply; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology*; D018721:Muscarinic Agonists / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D011928:Raynaud Disease / Q000503:physiopathology*; D012595:Scleroderma, Systemic / Q000503:physiopathology*; D013373:Substance P / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D018721:Muscarinic Agonists; D014665:Vasodilator Agents; D016210:Methacholine Chloride; D009599:Nitroprusside; D013373:Substance P; D001920:Bradykinin