Larger Image Figure 9. Estimating the number of channels underlying current fluctuations in symmetric DMA+ (A) Schematic depicting an excised patch in bi-ionic conditions of intracellular Na+ (Nai+) and extracellular DMA+ (DMA0+) with two CNGA1 channels present in the membrane patch. The arrows indicate the direction of the electrochemical driving force at +60 mV. In bi-ionic conditions, the cGMP-activated current at +60 mV was carried almost by Na+ ions moving from the bath solution toward the patch pipette. (B) Single-channel recording from the experimental conditions shown in A. Well-resolved openings slightly larger than those usually observed in symmetrical Na+ could be detected. Dashed line indicates the closed (C) state of the channel; O1 and O2 refer to the two open states. (C) All-point amplitude histogram from the electrical recording shown in B. Data were fitted with a three component Gaussian function (solid red line) indicating that two CNGA1 channels were present in the membrane patch. Image published in: Arcangeletti M et al. (2013) © 2013 The Authors. Creative Commons Attribution license Permanent Image Page Printer Friendly View XB-IMG-129472 |