Figure 1.

Chemical structure of chanoclavine and ergonovine and the inhibitory effects on Xenopus oocytes expressing human 5-hydroxytryptamine (5-HT)_3A receptors. (A). Structure of chanoclavine (EC) and ergonovine (EG). (B). After flowing 5-HT mixed with bath solution for one minute per 2 mL, 5-HT (100 µM) induced a reversible inward current (I_5-HT). The traces indicate the inward current in the presence of 5-HT coapplied with ergonovine and chanoclavine at 100 µM. The representative traces from four different frogs elicited at the −80-mV holding potential. (C). The histogram indicates that the percentage of inhibition by chanoclavine was 42.5 ± 9.7 calculated from the mean of the peak inward current. Each value represents the mean ± S.E.M (n = 8–10 from four different frogs).