Fig. 3: Extracellular adenosine generation in response to 40 Hz flickering in the primary visual cortex is mediated by ENT2.
From: 40 Hz light flickering promotes sleep through cortical adenosine signaling
a Schematic drawing depicting the production of Adenosine (Ado) from ATP via CD73 enzymes. b Extracellular adenosine increase (as detected by GRABAdo) caused by 40 Hz light flickering in V1 of WT and CD73-KO mice. c Quantified fluorescence of GRABAdo1.0 ΔF/F0 in response to 40 Hz light flickering in CD73-KO mice (n = 6/group). d Schematic drawing depicting the release of Ado via ENTs and the pharmacological inhibition of ENTs blocking activity. e Pretreatment with dipyridamole (30 min before light flickering) abolished 40 Hz flickering-induced extracellular adenosine generation during light flickering and after stimulation cessation. f Group summary of GRABAdo1.0 ΔF/F0 in response to 40 Hz light flickering application of dipyridamole (n = 5–6/group). g Description of metabolomic screening for dipyridamole administration h Total tissue (intracellular and extracellular) adenosine levels in V1, as assessed by HPLC analysis, after 40 Hz light flickering with or without pretreatment with dipyridamole (n = 14/group). *P < 0.05, comparing the dipyridamole-treated group with the vehicle-treated group. i Schematic drawing depicting the release of Ado via ENTs and blocking ENT1 activity in ENT1-KO mice. j 40 Hz flickering induced a robust and sustained increase of the extracellular adenosine generation in both WT and ENT1-KO mice, with slightly lesser induction in ENT1-KO than WT mice at later time points. k Group summary of GRABAdo1.0 ΔF/F0 in response to 40 Hz light flickering from ENT1-KO mice (n = 5–6/group). l Schematic drawing depicting the release of Ado via ENTs and blocking ENT2 activity by ENT2-KO mice. m 40 Hz flickering-induced extracellular adenosine generation was robust and sustained in WT but largely abolished in ENT2-KO mice. n Group summary of Ado1.0 ΔF/F0 in response to 40 Hz light flickering from ENT2-KO mice (n = 6–7/group). The data are presented as mean ± SEM, **P < 0.01, *P < 0.05, Student’s t-test; WT vs KO; dipyridamole-treated group vs vehicle group.
