Human vasodilator responses to a dopamine agonist: possible mechanisms.
The action of fenoldopam, a selective dopamine DA1 agonist, on resting forearm blood flow was studied in healthy male volunteers by venous plethysmography. Metoclopramide and (+/-) sulpiride were used as dopamine antagonists. Intra-arterial fenoldopam over the range (100 ng/min to 1 microgram/min) produced a dose-related increase in forearm blood flow without evidence of systemic effects. The response to fenoldopam was not antagonized by metoclopramide or (+/-) sulpiride and neither antagonist alone altered resting forearm blood flow. It is unclear whether the effects of fenoldopam in the forearm vasculature are mediated through the vascular dopamine receptor.
Redman
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D
St Mary's Hospital Medical School, London, UK.
Thom
S A
SA
Hughes
A D
AD
Hasan
S
S
Sever
P S
PS
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D000328:Adult; D015259:Dopamine Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018818:Fenoldopam; D005542:Forearm / Q000098:blood supply; D006801:Humans; D007269:Injections, Intra-Arterial; D008297:Male; D012039:Regional Blood Flow / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D015259:Dopamine Agents; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D018818:Fenoldopam