Aim:To study the subtypes and functional significance of dopamine (DA)
receptors in different rabbit arteries in vitro.Methods:Responses
of preconstricted vascular rings to selective DA receptor agonists and antagonists were examined.Results:①The efficacy and potency of fenoldopam in inducing relaxation varied comsiderably with different vessels.The relexation responses of renal and mesenteric arteries were most the potent to fenoldopam,but the
pulmonary artery was weaky responded to fenoldopam,femoral artery showed no response to fenoldopam.②PBDA induced concentration dependent relaxations in all the vessels studied.However,anong the four vessels the mes enteric and femoral arteries showed most potent relexations to PBDA;renal and pulmonary arteries showed weak responses to PBDA.③Among the vessels studied,only pulmonary artery showed endothelium dependent relaxing response to DA agonists;and ④the existence of DA 2
receptors in mesenteric and femoral arteries was further evidenced in 6 OHDA treated rabbits.Conclusions:DA receptors subtypes are distributed in different vascular beds.To clarify the heterogeneity in subtype and responsiveness of DA receptors in the peripheral circulation may help to evaluate the physiological significance of DA receptors in the four vascular beds.