(3H)-spiroperidol binding sites in the rabbit splenic artery

The topographic distribution of (3H)-spiroperidol binding sites (corresponding to dopamine receptors likely) was studied in rabbit splenic artery by the use of a histoautoradiographic technique. (3H)-spiroperidol was localized preferentially at the level of smooth muscle cells of the media as well as in close relation with cellular membrane of endothelial cells. The findings of a constant distribution of (3H)-spiroperidol binding sites within the medial layer of the splenic artery led us to hypothesize that these receptors mediate the relaxation of the splenic artery determined by dopamine infusion.