OBJECTIVE To investigate the role of 6,7-dimethoxycoumarin (DMOC) on α1-R,H1-R,M3-R and calcium channel.METHODS NE,histamine,KCl and phenylephedrinum were used to induce the contraction of the rabbit aortic strip.Atropine was added when NE was used to increase the perfusion pressure.RESULTS DMOC parallelly moved the dose-effect curve of histamine or NE,but the contraction could not reach the maximum at the large amount.It did not suppress the contraction to KCl,while reversed that to phenylephedrinum in Ca2+free Krebs solution.The effect of DMOC on the dose-effect curve of NE was not influenced by atropine on the isolated perfused kidney.CONCLUSION DMOC was the antagonist both for α1-R and H1-R and inhibited the release of Ca2+from sarcoplasmic reticulum.However,it did not have effect on voltage dependent Ca2+channel and M-3-R.