Astrocyte Kir4.1 expression level territorially controls excitatory transmission in the brain.

ABSTRACT: Intense brain activity elevates extracellular potassium, potentially leading to overexcitation and seizures. Astrocytes are crucial for restoring healthy potassium levels, and an emerging focus on their Kir4.1 channels has reopened the quest into the underlying mechanisms. We find that the Kir4.1 level in individual astrocytes sets the kinetics of their potassium and glutamate uptake current. Combining electrophysiology with multiplexed optical sensor imaging and FLIM reveals that rises in extracellular potassium would normally boost presynaptic Ca²⁺ entry and release probability at excitatory synapses unless such synapses are surrounded by the Kir4.1-overexpressing astrocytes. Inside the territories of Kir4.1-overexpressing astrocytes, high-frequency afferent stimulation fails

SUBMITTER: Tyurikova O 

PROVIDER: S-EPMC7618397 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature