Figure 4. Opening K channels can produce hyperpolarization. Membrane potential decreases (hyperpolarizes) in proportion to the number of K channels opened. Four different curves assuming opening K channels of different conductances (10, 15, 20, and 40 pS). The values of membrane potential were derived by using the following assumptions: total cell ionic conductance = 500 pS, EK=-90 mV, total K+conductance of 305 pS, total conductance for other ions (Na+, Ca++, and Cl-)= 195 pS. Modified from Quast et al. [104]