Perez M T, Ehinger B E, Lindström K, Fredholm B B
Brain Res. 1986 Nov 19;398(1):106-12. doi: 10.1016/0006-8993(86)91255-2.
The adenine nucleotide pool of rabbit retina was labeled by an intravitreal injection in vivo of [3H]adenosine. Practically all the radioactivity was retained in the form of adenine nucleotides. The relative proportion of [3H]adenine nucleotides was the same as that of endogenous nucleotides. Potassium depolarization (43.6 mM) in vitro caused a rapid increase in the rate of release of radioactive purines. The radioactive material was composed of hypoxanthine, xanthine, inosine and trace amounts of adenine, adenosine and adenine nucleotides. The release of radioactive purines was delayed and reduced by the addition of the nucleoside inhibitor dipyridamole suggesting that the purines may be released in the form of nucleosides. Similarly, the addition of the ecto 5'-nucleotidase inhibitor alpha, beta-methylene ADP (AOPCP) did not alter the release of radioactivity or the composition of the released purines. Endogenous hypoxanthine, xanthine and inosine could be detected in the effluents, but there was only a very modest increase following potassium depolarization. There was a slight, but significant, decrease in the release of endogenous adenosine and increase in AMP after AOPCP. It is concluded that there is an intensive uptake and phosphorylation of adenosine in the rabbit retina. Depolarization induces release of radioactive purine nucleosides and bases. Most of these compounds appear to be released as such, but in addition there may be a small (maximally a few per cent of the total) fraction of the purines that are released as nucleotides.
通过在体内玻璃体内注射[3H]腺苷来标记兔视网膜的腺嘌呤核苷酸池。实际上所有的放射性都以腺嘌呤核苷酸的形式保留。[3H]腺嘌呤核苷酸的相对比例与内源性核苷酸相同。体外钾去极化（43.6 mM）导致放射性嘌呤释放速率迅速增加。放射性物质由次黄嘌呤、黄嘌呤、肌苷以及痕量的腺嘌呤、腺苷和腺嘌呤核苷酸组成。核苷抑制剂双嘧达莫的加入延迟并减少了放射性嘌呤的释放，这表明嘌呤可能以核苷的形式释放。同样，ecto 5'-核苷酸酶抑制剂α，β-亚甲基ADP（AOPCP）的加入并未改变放射性的释放或释放的嘌呤的组成。在流出物中可检测到内源性次黄嘌呤、黄嘌呤和肌苷，但钾去极化后仅有非常适度的增加。AOPCP后内源性腺苷的释放略有但显著减少，AMP增加。结论是兔视网膜中存在腺苷的强烈摄取和磷酸化。去极化诱导放射性嘌呤核苷和碱基的释放。这些化合物中的大多数似乎就是以这种形式释放的，但此外可能还有一小部分（最多占总量的百分之几）嘌呤以核苷酸的形式释放。
