Changes in functional synaptic markers, synapsins I and II, in response to hypoxia.

<p>(<b>A,B</b>) Synapsins I and II mRNA levels in various brain structures of rats 30 min after exposure to hypoxia and their matched controls (n = 3, **P<0.01). (<b>C</b>) Immunohistological detection of synapsin I, synapsin II and phospho-synapsins (Ser⁹) in the CA1 layer of 21-day-old rats previously exposed to hypoxia and their matched controls (cells were counterstained by Dapi (blue) and by the neuronal protein NeuN (red). (<b>D–G</b>) <i>In situ</i> coupling between synapsins with phospho-Ser⁹ and phospho-Tyr³⁰¹, as monitored by the Duolink® “proximity ligation” assay: number of dots per cell in CA1 and frontal cortex (Cx) of 21-day-old control and hypoxic rats. Experiments were performed in triplicate (*<i>P</i><0.05, **<i>P</i><0.01). (<b>H,I</b>) Illustration of <i>in situ</i> association between synapsin I and phospho-Ser⁹ in the CA1 layer and the frontal cortex (Cx) of control and hypoxic rats, as revealed by red fluorescent dots in the Duolink® “proximity ligation” assay. Experiments were performed in triplicate, leading to similar results.