Premium
Modulation of K + conductance by intracellular pH in pancreatic β‐cells
Author(s) -
Rosario Luis M.,
Rojas Eduardo
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80539-7
Subject(s) - intracellular , biophysics , conductance , chemistry , collagenase , cytosol , membrane potential , islet , intracellular ph , fluorescence , beta cell , pancreatic islets , membrane , biochemistry , endocrinology , enzyme , biology , insulin , physics , mathematics , combinatorics , quantum mechanics
Measurements of the effects of NH 3 /NH 4 + on glucose‐induced electrical activity in β‐cells from microdis‐sected mouse islets of Langerhans and on intracellular pH in single collagenase‐isolated islets pre‐loaded with a fluorescent pH probe were performed and are reported here. Application of NH 3 /NH + 4 (15 mM) in the presence of glucose (11 mM) promptly hyperpolarized the β‐cell membrane, reduced input resistance by 60% and blocked electrical activity. These changes were paralleled by an increase in islet fluorescence indicative of a cytosolic pH increase. Removal of NH 4 Cl initially stumulated electical activity, which returned to resting level with a time constant of 51 s. Concomitant with the removal of NH 4 C1 there was a drop in pH i followed by a slow return to resting level with a time constant of 83 s. The results suggest that the [Ca 2+ ]‐dependent K + channel in the β‐cell membrane is activated by a rise in cytosolic pH.