Figure 3.
Determination of [Cl-]i in dendritic knobs. A, Dependence of fluorescence lifetimes in mouse olfactory epithelium on [Cl-]i. B, Determination of the Stern-Volmer constant (13 m-1) for MQAE in the tissue. Lifetime at 0 mm Cl- (τ0) was calculated from the curve in A. The data were obtained from a tissue preparation in which [Cl-]i of OSNs and supporting cells was set to the indicated values using Cl- ionophores and the standard solutions listed in Table 1. C, [Cl-]i in dendritic knobs of rat (left) and mouse (right) olfactory epithelium at an extracellular [Cl-] of 50 mm, corresponding to the mucosal [Cl-] in vivo. Mean values are 54 ± 4 mm in rat (96 knobs) and 37 ± 6 mm in mouse (406 knobs). Scale bar, 10 μm.