Jonsson Gudmundur, Eysteinsson Thor
Department of Physiology,University of Iceland,Reykjavik,Iceland.
Vis Neurosci. 2017 Jan;34:E001. doi: 10.1017/S0952523816000171.
Adenosine is a neuromodulator present in various areas of the central nervous system, including the retina. Adenosine may serve a neuroprotective role in the retina, based on electroretinogram (ERG) recordings from the rat retina. Our purpose was to assess the role of A2A and A3 adenosine receptors in the generation and modulation of the rat ERG. The flash ERG was recorded with corneal electrodes from Sprague Dawley rats. Agonists and antagonists for A2A and A3 receptors, and adenosine were injected (5 µl) into the vitreous. The effects on the components of the single flash scotopic and photopic ERGs were examined, and ERG flicker. Adenosine (0.5 mM) increased the mean amplitudes of the scotopic ERG a-waves (68 ± 8 to 97 ± 14 µV, P = 0.042), and b-waves (236 ± 38 µV to 305 ± 42 µV). A2A agonist CGS21680 (2 mM) reduced the mean amplitude of the ERG b-wave, from 298 ± 21 µV in response to the brightest stimulus to 212 ± 19 µV (P = 0.005), and mean scotopic oscillatory potentials (OPs) from 100 ± 9 µV to 47 ± 11 µV (P = 0.023). ZM241385 [4 mM], an A2A antagonist, decreased the scotopic b-wave of the ERG. A3 agonist 2-CI-IB-MECA (0.5 mM) increased the a-wave, while decreasing the scotopic and photopic ERG b-waves, and the scotopic OPs. A3 antagonist VUF5574 (1 mM) increased the mean amplitude of the scotopic a-wave (66 ± 8 to 140 ± 29 µV, P = 0.046) and b-wave (224 ± 20 to 312 ± 39 µV, P = 0.0037). No significant effects on ERG flicker were found. We conclude that retinal neurons containing A2A and/or A3 adenosine receptors contribute to the generation of the ERG a- and b-waves and OPs.
腺苷是一种神经调质，存在于包括视网膜在内的中枢神经系统的各个区域。基于大鼠视网膜的视网膜电图（ERG）记录，腺苷可能在视网膜中发挥神经保护作用。我们的目的是评估A2A和A3腺苷受体在大鼠ERG的产生和调节中的作用。用角膜电极记录Sprague Dawley大鼠的闪光ERG。将A2A和A3受体的激动剂和拮抗剂以及腺苷（5微升）注入玻璃体。检查对单次闪光暗视和明视ERG各成分以及ERG闪烁的影响。腺苷（0.5毫摩尔）增加了暗视ERG a波的平均振幅（从68±8微伏增加到97±14微伏，P = 0.042）以及b波的平均振幅（从236±38微伏增加到305±42微伏）。A2A激动剂CGS21680（2毫摩尔）使ERG b波的平均振幅从对最亮刺激的298±21微伏降低到212±19微伏（P = 0.005），并使暗视振荡电位（OPs）的平均振幅从100±9微伏降低到47±11微伏（P = 0.023）。A2A拮抗剂ZM241385 [4毫摩尔]降低了ERG的暗视b波。A3激动剂2 - CI - IB - MECA（0.5毫摩尔）增加了a波，同时降低了暗视和明视ERG b波以及暗视OPs。A3拮抗剂VUF5574（1毫摩尔）增加了暗视a波的平均振幅（从66±8微伏增加到140±29微伏，P = 0.046）以及b波的平均振幅（从224±20微伏增加到312±39微伏，P = 0.0037）。未发现对ERG闪烁有显著影响。我们得出结论，含有A2A和/或A3腺苷受体的视网膜神经元有助于ERG a波、b波和OPs的产生。
