(A) Representative traces of single channel activities in rat glomus cells. Note the large increase in overall activity with halothane and a more modest increase from control with isoflurane alone. Also shown (lowest trace) is the effect of a mix of agents (2.5% of each agent is shown) from which it appears that the activities are perhaps a little more than isoflurane alone but clearly less than halothane alone. In each recording, washout restored the activities back to the level of control. (B) Quantitative analysis of channel open probability (nPopen) activities for halothane (red) and isoflurane (purple) and mix of equal concentrations of agent administered (1.5% + 1.5%, 2.5% + 2.5%, and 4% + 4%; green symbols: see Supplementary Digital Content, figure S3 (https://links.lww.com/ALN/C467), for total aqueous concentrations). Values are mean ± SD (unidirectional bars for clarity), n = 176 patches in separate cells performed. The x-axis is plotted to indicate the concentration of total agent. The red and purple lines (for halothane and isoflurane, respectively) are the result of applying Equation 1 to the data, from which individual agent Kd and Bmax were estimated. The green line is the result of applying Equation 2 using these Kd and Bmax values.