Effect of AMG-1 and adenosine on glutamate release from synaptosomes in rats
Liu, L.; Feng, Y.P.
Yao Xue Xue Bao 28(12): 881-885
1993
ISSN/ISBN: 0513-4870 PMID: 8030410 Document Number: 405269
The effects of AMG-1 (6(5-hydroxy-2-methylpyridyiamino)-9-ribofranosylpurine), an adenosine analogue, and adenosine on Ca-2+-dependent and independent release of glutamate from rat synaptosomes induced by KCl 30 mmol cntdot L-1 were studied with an enzyme-linked fluorometric assay. The synaptosomes were prepared and preincubated for 30 min at 37 degree C. Two ml of incubation mixture containing synaptosomes (1.27 mg protein), NADP+ 1 mmol cntdot L-1, L-glutamic dehydrogenase 50 U, CaCl-2 1.3 mmol cntdot L-1 (or EGTA 1. 3 mmol cntdot L-1 was transferred to the stirred cuvette in the fluorometer at 37 degree C. for 5 min. Then, AMG-1 (or adenosine) was added. Released glutamate (eg. fluorescent intensity) was monitored following the addition of 30 mmol cntdot L-1 KCl. The results indicate that Ca-2+-dependent glutamate release from depolarized synaptosomes is inhibited by AMG-1 (0.1 mmol cntdot L-1) or adenosine (0.3 mmol cntdot L-1). The action of AMG-1 seems to be similar to that of adenosine. However, no change was found on Ca-2+-independent release of glutamate. This implies that the protective effect of AMG-1 against cerebral ischemia may be partially due to inhibiting glutamate release from nerve terminal via the activation of adenosine A-1 receptor.