Maehara T, Suzuki H, Yoshioka K, Otsuka M
Department of Neurosurgery, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Neuroscience. 1995 Sep;68(2):577-84. doi: 10.1016/0306-4522(95)00153-a.
The characteristics of release of amino acids evoked by substance P from the neonatal rat spinal cord were examined. A hemisected spinal cord was continuously perfused and the release of amino acids into the perfusate was measured using high-performance liquid chromatography with a precolumn derivatization technique. Substance P (10 microM) evoked a significant increase in the release of aspartate, glutamate, GABA, glycine and taurine. The substance P-evoked release of these five amino acids was not reduced by Ca(2+)-free medium, but was blocked by [D-Pro4,D-Trp] substance P4-11 (10 microM). Perfusion of the spinal cord with low-Na+ medium (22 mM) induced a marked increase in the high-K+ (90mM)-evoked release of GABA, glutamate and glycine. In contrast, the substance P-evoked release of the five amino acids was significantly decreased by the low-Na+ medium. Similarly, perfusion of the spinal cord with low-Cl- medium (8 mM) increased the high-K(+)-evoked release of GABA and glycine, but decreased the substance P-evoked release of GABA, glycine and taurine. The substance P-evoked release of the five amino acids was dose-dependently blocked by d-tubocurarine (3-10 microM), whereas it was not blocked by tetrodotoxin (0.2 microM) or amiloride (30 microM). Compound 48/80 (10 micrograms/ml), a histamine-releasing agent on mast cells, evoked release of the amino acids from the spinal cord with characteristics similar to those of substance P-evoked amino acid release.(ABSTRACT TRUNCATED AT 250 WORDS)
研究了P物质从新生大鼠脊髓诱发的氨基酸释放特征。将脊髓半横切后持续灌注，并采用柱前衍生化技术的高效液相色谱法测量灌注液中氨基酸的释放。P物质（10微摩尔）可显著增加天冬氨酸、谷氨酸、γ-氨基丁酸、甘氨酸和牛磺酸的释放。P物质诱发的这五种氨基酸的释放不受无钙培养基的影响，但被[D-脯氨酸4，D-色氨酸]P物质4-11（10微摩尔）阻断。用低钠培养基（22毫摩尔）灌注脊髓可显著增加高钾（90毫摩尔）诱发的γ-氨基丁酸、谷氨酸和甘氨酸的释放。相反，低钠培养基可显著降低P物质诱发的这五种氨基酸的释放。同样，用低氯培养基（8毫摩尔）灌注脊髓可增加高钾诱发的γ-氨基丁酸和甘氨酸的释放，但可降低P物质诱发的γ-氨基丁酸、甘氨酸和牛磺酸的释放。P物质诱发的这五种氨基酸的释放呈剂量依赖性地被筒箭毒碱（3-10微摩尔）阻断，而不被河豚毒素（0.2微摩尔）或阿米洛利（30微摩尔）阻断。化合物48/80（10微克/毫升）是一种肥大细胞组胺释放剂，可诱发脊髓释放氨基酸，其特征与P物质诱发的氨基酸释放相似。（摘要截短于250字）
