摘要：

1. 1.|It is suggested that the P 2-purinoceptor may be separated into two subtypes largely on the basis of the rank order of agonist potency of structural analogues of ATP and also on the activity of antagonists at the P 2-purinoceptor: Subtype 1 (designated P 2X) 2. (i)|potency order: α, β-methyleneATP, β, γ-methyleneATP > ATP = 2 methylthioATP; 3. (ii)|antagonism by ANAPP 3 and selectively desensitisation following administration of α,β-methyleneATP; 4. (iii)|present in the vas deferens and urinary bladder of guinea-pig and rat, frog and rat ventricle, and also in the smooth muscle of the rat femoral artery and rabbit central ear artery, where they mediate excitation. Subtype 2 (designated P 2Y) 5. (i)|potency order: 2-methylthioATP ⪢ ATP > α, β-methyleneATP, β, γ-methyleneATP; 6. (ii)|weak antagonism by ANAPP 3 and desensitisation following administration of α,β-methyleneATP; 7. (iii)|present in the guinea-pig taenia coli and the longitudinal muscle layer of the rabbit portal vein, where they mediate relaxation, and also on the vascular endothelial cells of the rat femoral artery and pig aorta (where occupation leads to the production of endothelium-derived relaxing factor). 8. 2.|Differences in the structure of the P 2-purinoceptor in various tissues may be useful in the development of drugs for the treatment of vascular, gastrointestinal and urinoglenital disorders.

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