New Double-Barreled, Ion-Sensitive Microelectrodes for Measuring Intracellular Cl- Activities in Rabbit Renal Collecting Ducts.

Abstract

The use of the conventional ion-sensitive double-barreled microelectrodes has been unsuccessful for studying small epithelial cells such as those of the collecting duct because of the difficulty in obtaining the ideal electrodes for impaling cells. We developed a new type of ion-sensitive, double-barreled microelectrode of a size and tip configuration ideal for use in impaling small cells such as the principal cells (PCs) of the cortical collecting ducts, and remaining therein, for more than 30 min. The electrodes were pulled in two steps. The first includes the reciprocal twisting of two parallel glass capillaries, without pulling, to form a round, nontortuous fused glass capillary in the puller. In the second step, the round, fused straight capillaries are pulled so as to form the tip. This resulting procedure enabled us to impale the PCs without altering their cell membrane potentials. The basolateral membrane voltage (Vb) in PCs of the cortical collecting ducts was -69.1±1.6 mV (n=8) and intracellular C1-activity ([C1],) in PCs of the cortical collecting duct was 11.8±0.9 mmol/liter (n=5).Changing the concentration of C1-in the ambient solution showed that the basolateral cell membrane of the PCs was highly permeable to Cl-. This new electrode will help to obtain new information on intracellular ion handling, with the electrodes applied to the collecting duct cells. chloride transport ; ion exchanger; renal tubule ; electrophysiology ; aluminosilicate glassThe use of the ion-sensitive microelectrodes in studies of renal electrophysiology has provided considerable information on the mechanism of ion transport across the cell membrane of the renal tubule. Such studies have revealed, for instance, that the renal proximal tubular cells maintain a very low level of cellular Na+ by accumulating K+ into the cells, and that the cellular pH is kept slightly basic by several acid-extruding mechanisms such as the Na+/H+

A four-electrode method to study dynamics of ion activity and transport in skeletal muscle fibers

“…Prior studies with self-referencing ISMs constructed from double-barreled theta glass capillaries often showed signs of fiber damage with low resting potentials and unstable recordings with drift ( Aickin and Brading, 1982 ; Kondo et al, 1993 ). Our design with separate V ref and V ISM electrodes allows for smaller tip sizes than typically used with theta glass, which may account for the improved fiber viability.…”

Vasopressin stimulates Cl- transport in ascending thin limb of Henle's loop in hamster.

“…not successful because the dye was not sufficiently loaded. Intracellular Cl -concentration measurement with double-barreled, ion-selective microelectrodes, as described by Kondo et al (24), is also impossible in ATL cells because they are too small to impale. Therefore we cannot clarify this point at this moment.…”

Is resting state HCO3‐ secretion in frog gastric fundus mucosa mediated by apical Cl(‐)‐HCO3‐ exchange?

“…Tissues were kept in the resting state by adding 0-1 mm cimetidine (Sigma) to the serosal solution. Microelectrodes Double-barrelled pH microelectrodes were constructed as described by Kondo, Igarashi, Abe & Tada (1993). Briefly, two sections of filament-containing aluminum silicate glass tubing of different diameters (1-5 mm o.d.…”