No evidence for dopamine-induced relaxation in isolated human mesenteric arterial strips from elderly patients

1. We investigate the effects of dopamine in isolated mesenteric artery from elderly patients. 2. Noradrenaline (10(-11) to 10(-4) M) and dopamine (2.7 x 10(-6) to 1.4 x 10(-3) M) induced a concentration-dependent contraction that was antagonized by prazosin. Fenoldopam (10(-8) to 10(-4) M) and clonidine (10(-9) to 10(-4) M) did not produce any contractile effects. 3. Potassium chloride (80 mM) produced a well-maintained plateau contraction and dopamine-induced contraction in these conditions, which was decreased by prazosin (10(-8) M). Neither fenoldopam nor isoprenaline (10(-10) to 10(-5) M) modified the well-maintained plateau. 4. Our results suggest that post-synaptic dopamine receptors are not present in this preparation but alpha1-adrenoceptors are present.