Contrasting effects of epinephrine on forearm hemodynamics and arterial plasma norepinephrine.
Circulating catecholamines are widely considered to cause vasoconstriction. However, in the present study an intravenous infusion of 0.01 micrograms/kg/min epinephrine for 10 min in healthy men (n = 40, 20 to 40 years of age), which raised arterial plasma epinephrine from 100 +/- 13 to 231 +/- 22 pg/mL (mean +/- SE), increased forearm blood flow (FBF) from 2.79 +/- 0.17 to 3.45 +/- 0.25 mL/100 forearm tissue/min (P < .001), and decreased forearm vascular resistance (FVR) from 37.0 +/- 2.4 to 31.1 +/- 2.1 (arbitrary units). Further stepwise increase in epinephrine infusion rate progressively raised FBF (to a maximum 6.91 +/- 0.46) and decreased FVR (to minimum 16.7 +/- 2.0), and increased arterial plasma norepinephrine by more than 60% (P < .001). Thus, circulating epinephrine in concentrations that can be produced by mental stress has, despite its ability to increase sympathetic drive, a regional vasodilating effect in the human forearm.
Kjeldsen
S E
SE
Department of Internal Medicine, Ullevaal University Hospital, Oslo, Norway.
Petrin
J
J
Weder
A B
AB
Julius
S
S
D000328:Adult; D000368:Aged; D001158:Arteries; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology*; D005542:Forearm / Q000098:blood supply*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D009994:Osmolar Concentration; D012039:Regional Blood Flow / Q000187:drug effects
D009638:Norepinephrine; D004837:Epinephrine