Modulation of K+ conductance by intracellular pH in pancreatic β‐cells

FEBS Letters

Rosario, Luis M.¹  Rojas, Eduardo¹ 

[1]Laboratory of Cell Biology and Genetics, National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Building 4, Room 312, Bethesda, MD 20205, USA

关键词: Sulfofluorescein diacetate intracellular pH K+ conductance (Pancreatic β-cell);   

DOI  :  10.1016/0014-5793(86)80539-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Measurements of the effects of NH₃/NH₄ ⁺ 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 NH₃/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 NH₄Cl initially stumulated electical activity, which returned to resting level with a time constant of 51 s. Concomitant with the removal of NH₄C1 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 [Ca²⁺]-dependent K⁺ channel in the β-cell membrane is activated by a rise in cytosolic pH.

【 授权许可】

Unknown