de Lima Denise Sandrelly Cavalcanti, Maia Luciana Maria Silva de Seixas, Barboza E'lida de Andrade, Duarte Raísa de Almeida, de Souza Laís Santos, Guedes Rubem Carlos Araújo
Department of Nutrition, Universidade Federal de Pernambuco, 50670901 Recife, PE, Brazil.
Life Sci. 2009 Jul 31;85(5-6):241-7. doi: 10.1016/j.lfs.2009.05.017. Epub 2009 Jun 7.
Glutamine (Gln) participates in the so-called "brain glutamine-glutamate cycle" and therefore it is likely to influence brain excitability. Here we investigated, in weaned well-nourished and early-malnourished rats, the effects of previous Gln oral supplementation, during the brain development period, on cortical spreading depression (CSD), an excitability-related brain phenomenon.
Male Wistar (W) suckling rat pups, well-nourished (litters with 6 pups) and malnourished (M) during lactation (by increasing the litters to 12 pups), received Gln (500 mg/kg/day) by gavage during postnatal days 7 to 27. At 30-40 days of life, they were submitted to a cortical spreading depression (CSD) recording session during 4 h, on 2 cortical parietal points of the right hemisphere. CSD velocity propagation was calculated from the time required for a CSD wave to cross the inter-electrode distance.
In both nutritional condition, Gln rats presented higher (p<0.05) CSD propagation velocities (W-Gln, 4.22+/-0.23; M-Gln, 4.51+/-0.27 mm/min), as compared to water-treated controls (W-Wa, 3.77+/-0.21; M-Wa, 4.15+/-0.18 mm/min). This water control group did not differ from a naive control group that was not submitted to the gavage procedure. A fourth group, treated with a "placebo amino acid" (glycine), also displayed CSD velocities in the control range.
The results indicate that Gln supplementation during brain development facilitates cortical spreading depression propagation, as judged by the higher CSD velocities, and this effect is not abolished by malnutrition. Data support the idea of Gln-related changes in brain excitability, during neural development.
谷氨酰胺（Gln）参与所谓的“脑谷氨酰胺 - 谷氨酸循环”，因此它可能会影响脑兴奋性。在此，我们研究了在断奶后营养良好和早期营养不良的大鼠中，在脑发育期间先前口服补充Gln对皮层扩散性抑制（CSD）的影响，CSD是一种与兴奋性相关的脑现象。
雄性Wistar（W）乳鼠幼崽，在哺乳期营养良好（每窝6只幼崽）和营养不良（M）（通过将每窝幼崽增加到12只），在出生后第7至27天通过灌胃给予Gln（500 mg/kg/天）。在30 - 40日龄时，在右半球的2个皮层顶叶点进行4小时的皮层扩散性抑制（CSD）记录。根据CSD波穿过电极间距离所需的时间计算CSD速度传播。
在两种营养状况下，与水处理对照组（W - Wa，3.77±0.21；M - Wa，4.15±0.18 mm/min）相比，Gln处理的大鼠呈现出更高（p<0.05）的CSD传播速度（W - Gln，4.22±0.23；M - Gln，4.51±0.27 mm/min）。这个水对照组与未进行灌胃程序的未处理对照组没有差异。第四组用“安慰剂氨基酸”（甘氨酸）处理，其CSD速度也在对照范围内。
结果表明，在脑发育期间补充Gln可促进皮层扩散性抑制的传播，从较高的CSD速度判断，并且这种作用不会因营养不良而消除。数据支持了在神经发育过程中与Gln相关的脑兴奋性变化的观点。
