Yashuda Y, Cabral A M, Pires J G, Antonio A
Gen Pharmacol. 1983;14(6):643-7. doi: 10.1016/0306-3623(83)90161-1.
The contractile responses elicited by calcium (Ca) and barium (Ba) upon the isolated rat duodenum immersed in a Ca-free Tyrode solution are not nervously mediated and are differently affected by epinephrine (E), cocaine (C) and verapamil (V). E antagonizes Ca but not Ba while C inhibits only Ba. The antagonism of V is greater towards Ba than Ca. The different influence of the drugs disappear in the excess potassium-depolarized duodenum. Thus, C and V block equally Ca and Ba, while E is only slightly effective against the two cations.
钙（Ca）和钡（Ba）对浸于无钙台氏液中的离体大鼠十二指肠引发的收缩反应并非由神经介导，且受到肾上腺素（E）、可卡因（C）和维拉帕米（V）的不同影响。E拮抗Ca但不拮抗Ba，而C仅抑制Ba。V对Ba的拮抗作用比对Ca更强。在过量钾去极化的十二指肠中，这些药物的不同影响消失。因此，C和V对Ca和Ba的阻断作用相同，而E对这两种阳离子仅有轻微作用。
