FIGURE 3.

α-Conotoxin TxIB blocks α6/α3β2β3 nAChRs. A, Xenopus oocytes expressing α6/α3β2β3 nAChRs were voltage clamped at −70 mV and subjected to a 1-s pulse of ACh every minute as described under “Experimental Procedures.” A representative response in a single oocyte is shown. After control responses to ACh, the oocyte was exposed to 1 μm α-CTx TxIB for 5 min. Toxin was then washed out and the response to ACh was again measured (arrow). B, concentration response of α6/α3β2β3 nAChRs exposed to α-CTx TxIB and α-CTx TxIB(G). Values shown in the graph are mean ± S.E. from 3–10 separate oocytes.