Presynaptic modulation of amino acid release from synaptosomes
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Using synaptosomes prepared from whole rat brain, the spontaneous, calcium-independent, and calcium-dependent release of glutamate and GABA was assessed. Time intervals of 1–30 seconds were studied. Spontaneous release of glutamate (but not GABA) was elevated by 10 μM NMDA or AMPA by thirty seconds. This stimulation was partially calcium-dependent. Calcium-dependent release induced by 30 mM KCl was biphasic, confirming previous findings. This release was stimulated at all time periods by the presence of 10 μM NMDA or AMPA in an antagonist-sensitive manner. These data suggest that glutamate and GABA are released from vesicular stores in rat synaptosomes and that some of this release is modulated by presynaptic glutamate receptors.
Key WordsGlutamate GABA NMDA synaptosomes
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- 6.Wilkinson, R., and Nicholls, D. G. 1989. Compartmentation of glutamate and aspartate within cerebral cortical synaptosomes: evidence for a non-cytoplasmic origin for the Ca2+-releasable pool of glutamate. Neurochem Int 15:191–197.Google Scholar
- 9.Turner, T. J., and Goldin, S. M. 1989. Multiple components of synaptosomal [3H] ϖ aminobutyric acid release resolved by a rapid superfusion system. Biochem 28:586–593.Google Scholar
- 11.Monaghan, D. T., Bridges, R. J., and Cotman, C. W. 1987. Excitatory amino acid receptors: their classes, pharmacology, and distinct properties in the function of the central nervous system. Ann Rev Pharmacol Toxicol 29:365–402.Google Scholar
- 21.Barrie, A. and Nicholls, D. G. 1988. Presynaptic regulation of glutamate release from guinea pig cortical synaptosomes. Biochem Soc Trans 16:881–882.Google Scholar
- 24.Sherman, A. D. 1988. Isolation of metabolically distinct synaptosomes on Percoll gradients. Neurochem. Res. 14:97–101.Google Scholar
- 25.Lenda, K., and Svenneby, G. 1980. Rapid high performance liquid chromatographic determination of amino acids in synaptosomal extracts. J Chromatog 198:516–519.Google Scholar
- 31.Sherman, A. D. 1991. Depolarization and synaptosomal glutamine utilization. Neurochem Res (in press).Google Scholar
- 32.Kawagoc, R., Onodera, K., and Takeuchi, A. 1982. On the quantal release of endogenous glutamate from the crayfish neuromuscular junction. J Physiol (Lond). 322:529–539.Google Scholar