Decreased vascular responsiveness to noradrenaline following regular ethanol consumption

Ten normal volunteers consumed 80 g of ethanol per day or abstained from ethanol for 4 consecutive days prior to measurements of blood pressure, heart rate, vascular responsiveness to noradrenaline (NA) and angiotensin II (AII) infusions and sympathetic responsiveness to isometric handgrip exercise in an open, random order, crossed study. Supine systolic and diastolic pressures and heart rates, and erect systolic pressures rose significantly following ethanol. Vascular responsiveness to NA infusions was reduced in all subjects following ethanol, while responses to AII infusions did not show a consistent pattern of change. Plasma renin activity, plasma NA and adrenaline concentrations, and concentrations of the NA metabolite 3,4 dihydroxyphenylethylene glycol (DHPG) did not significantly differ following ethanol and control treatments. The rise in plasma NA following 2 min isometric handgrip at 50% of maximal effort was greater following ethanol (0.24 +/- 0.21 nM) than control (0.12 +/- 0.10 nM) but the difference did not reach statistical significance. The pressor effect of regular ethanol consumption and the reduced vascular reactivity to NA may both be the result of an increase in sympathetic activity that was not large enough to measurably alter resting plasma NA concentrations.