Fig. 10From: Fluid and ion transfer across the blood–brain and blood–cerebrospinal fluid barriers; a comparative account of mechanisms and rolesUnidirectional Cl− influx into parietal cortex as a function of [Cl−]plasma. The Cl− influx has been calculated as the transfer constant, k, taken from Fig. 3a in [269] times [Cl−]plasma. The short-dashed curve is plotted using the expression for transport by a saturable transporter with k = V max /(K m + [Cl−]plasma), maximum transport rate, V max = 250 mM s−1, and Michaelis constant, K m = 43 mM as described by Smith and Rapoport [269]. The solid curve is the best fit for a model with a single saturable component plus an unsaturable component. 53% of the influx is unsaturable at [Cl−]plasma = 118 mM. As shown by the long-dashed line, it is even possible to fit the data more closely than by Smith and Rapoport’s expression by assuming a high affinity, saturable component and an unsaturable component with 72% of the uptake unsaturable at 118 mM. The fitting is described in more detail in footnote 14Back to article page