The action of dopamine and vascular dopamine (DA1) receptor agonists on human isolated subcutaneous and omental small arteries

Human small arteries were obtained from surgical specimens and studied in vitro by use of a myograph technique. Following induction of tone with a potassium depolarizing solution, dopamine in the presence of beta-adrenoceptor and catecholamine uptake blockade relaxed isolated omental and subcutaneous arteries. Preincubation of tissues with phentolamine increased the maximum relaxation in response to dopamine. 2. The selective vascular dopamine receptor agonists, fenoldopam and SKF 38393 also relaxed isolated subcutaneous and omental arteries in a concentration-dependent manner. The order of potency for agonists was dopamine greater than fenoldopam greater than SKF 38393. 3. Dopamine-induced relaxation was competitively antagonized by SCH 23390, (R)- and (S)-sulpiride, and fenoldopam induced relaxation by SCH 23390 and (+)- but not (-)-butaclamol. 4. These results indicate the presence of vascular dopamine receptors (DA1 subtype) on human isolated resistance arteries from omental and subcutaneous sites.