Cold-induced potentiation of alpha 2-adrenergic vasoconstriction in primary Raynaud's disease.
OBJECTIVE
To determine the effects of local cooling on alpha-adrenergic responses in the fingers of patients with idiopathic Raynaud's disease.


METHODS
Clonidine HCl and phenylephrine HCl were administered through a brachial artery catheter while blood flow was measured by plethysmography in cooled and uncooled fingers.


RESULTS
Cooling potentiated alpha 2-adrenergic vasoconstriction in the patients but depressed this response in the controls. Vasoconstrictive responses to phenylephrine were not significantly affected by cooling but were significantly greater in the patients than in the controls.


CONCLUSIONS
Cold-induced sensitization of peripheral vascular alpha 2-adrenoceptors may be involved in the mechanism by which cooling triggers the vasospastic attacks of Raynaud's disease.
Department of Psychiatry, Wayne State University School of Medicine, Detroit, Michigan.
R R
RR
Freedman
M
M
Moten
P
P
Migály
M
M
Mayes
D000328:Adult; D003000:Clonidine / Q000494:pharmacology*; D003080:Cold Temperature / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005385:Fingers / Q000098:blood supply*; D006801:Humans; D008875:Middle Aged; D010656:Phenylephrine / Q000494:pharmacology*; D011928:Raynaud Disease / Q000503:physiopathology*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D012039:Regional Blood Flow / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D003000:Clonidine