[Effect of 4-aminopyridine on Taurine-regulated Release of Amino Acid from Rat Cortical Synaptosomes]

Aim: To elucidate the mechanism of taurine-regulated amino acid release from synaptosomes.

Methods: Endogenous aspartate, glutamate and GABA release from cortical synaptosomes were measured by high performance liquid chromatography using stepwise elution system, Glutamate release was monitored by continuous fluorometry.

Results: 4-Aminopyridine (3.0 x 10(-2) mol.L-1) counteracted the taurine-induced inhibition of glutamate overflow (P < 0.05), while aspartate and GABA release was not affected. Nimodipine (10(-5) mol.L-1) combined with 4-aminopyridine was shown to decrease glutamate release (P < 0.05).

Conclusion: Taurine may regulate glutamate release through presynaptic L-type calcium channel and also act on Asp- and GABA-nereve terminal to regulate Asp and GABA release in rat cortex.