Figure 2. AMPA receptor evoked adenosine release depends upon a Na⁺ influx in cortex and basal forebrain.

A) Adenosine biosensor recording, showing that when 80% of Na⁺ was substituted with NMDG⁺, AMPA (5 µM) could not evoke adenosine release in basal forebrain (BFB) or cortex (CTX). Re-introduction of Na⁺ restored AMPA-evoked adenosine release. B) Summary data showing that AMPA-evoked adenosine release in BFB and cortex is completely dependent on extracellular Na⁺ (n = 6). C) High K⁺-evoked adenosine release depends upon extracellular Na⁺ in BFB but not in cortex (n = 6). D,E) AMPA-evoked adenosine release was substantially blocked by TTX. f) TTX also blocked high K⁺-evoked adenosine release in cortex (control, n = 10; TTX n = 12). Statistical comparisons via Student's unpaired t-test.