Characteristics of nitric oxide-evoked [H]taurine release from cerebral cortical neurons

Pharmacological characteristics of ³H]taurine release evoked by nitric oxide (NO) were investigated using mouse cerebral cortical neurons in primary culture. NO generators such as S-nitroso-N-acetylpenicillamine (SNAP) and sodium nitroprusside (SNP) dose-dependently increased ³H]taurine release from neurons. Such stimulatory effects of NO generators were completely abolished by hemoglobin, a NO radical scavenger, indicating that these ³H]taurine releases might be due to NO liberated from SNAP and SNP. Sodium withdrawal from incubation buffer significantly inhibited the SNAP- and SNP-induced ³H]taurine releases, whereas the removal of calcium showed no alterations in the ³H]taurine release evoked by NO generators. β-Alanine and guanidinoethane sulfonate, inhibitors of carrier-mediated taurine transport system, inhibited the SNAP- and SNP-evoked releases of ³H]taurine in a dose-dependent manner. These results indicate that the NO-evoked ³H]taurine release from cerebral cortical neurons is mediated by the reverse process of sodium-dependent carrier-mediated taurine transport system.