Figure 2. Evaluation of whether cytoplasmic soluble elements and G proteins contribute to the response generation.
A, response of a membrane patch to quinine recorded 4, 5, 8 and 14 min after membrane excision. Quinine (5 mM) was ejected from a puffer pipette with a pressure of 10 kPa at the times indicated by the bars over the current traces. The holding voltage was -54 mV. B, magnitude of the integrated response of A as expressed by the amount of charge generated during quinine application. C, current response to quinine (1 mM, ejected from a puffer pipette with a pressure of 20 kPa) recorded 3.6 min after membrane excision with a patch pipette containing 1 mM GDPβS. The holding voltage was -79 mV. D, current response (1 mM, ejected from a puffer pipette with a pressure of 30 kPa) recorded 4.0 min after membrane excision with a patch pipette containing 1 mM GTPγS. The holding voltage was -54 mV. For all panels the bath solution contained 115 mM NaCl, 2.5 mM KCl (no Ca2+ added) and the patch pipette solution contained 120 mM CsCl.