Löscher W, Wahnschaffe U, Rundfeldt C, Hönack D, Hoppen H O
Department of Pharmacology, Toxicology, and Pharmacy, School of Veterinary Medicine, Hannover, Germany.
Neurochem Res. 1992 Oct;17(10):973-7. doi: 10.1007/BF00966823.
Concentrations of 11 amino acids, including the neurotransmitters GABA, glutamate, aspartate, glycine and taurine, were determined in 12 brain regions of female rats during different stages of the estrous cycle. In addition, amino acids and sex hormone levels were determined in plasma. All sample collections were done in the forenoon between 9 and 11 a.m. Most regional amino acid levels measured did not change significantly during estrous cycle, but significant alterations were found for GABA and glutamate in hypothalamus. Both amino acids were slightly decreased in hypothalamus during proestrus, which might reflect an alteration of GABA turnover in response to the high estrogen levels during this stage. A decreased glutamate level during proestrus was also found in thalamus, while both glutamate and GABA did not vary throughout estrous cycle in any of the other examined regions, including substantia nigra, amygdala, striatum, cortex and hippocampus. When diestrus was subdivided according to progesterone levels, high levels of this hormone seemed to be associated with effects on metabolism of certain amino acids, including glycine in substantia nigra, alanine in thalamus and threonine in pons/medulla. However, the few changes in regional amino acid concentrations found during the estrous cycle were so small that the functional significance of these changes cannot be ascertained without further determination of the cellular or subcellular compartments of brain tissue involved.
在雌性大鼠发情周期的不同阶段，测定了包括神经递质γ-氨基丁酸（GABA）、谷氨酸、天冬氨酸、甘氨酸和牛磺酸在内的11种氨基酸在12个脑区的浓度。此外，还测定了血浆中的氨基酸和性激素水平。所有样本采集均在上午9点至11点之间进行。在发情周期中，所测的大多数脑区氨基酸水平没有显著变化，但下丘脑的GABA和谷氨酸有显著改变。在发情前期，下丘脑的这两种氨基酸均略有下降，这可能反映了在此阶段对高雌激素水平的反应，GABA周转率发生了改变。在丘脑也发现发情前期谷氨酸水平下降，而在包括黑质、杏仁核、纹状体、皮质和海马体在内的任何其他检测区域，谷氨酸和GABA在整个发情周期中均无变化。根据孕酮水平对动情间期进行细分时，这种激素的高水平似乎与对某些氨基酸代谢的影响有关，包括黑质中的甘氨酸、丘脑中的丙氨酸和脑桥/延髓中的苏氨酸。然而，在发情周期中发现的区域氨基酸浓度的变化很小，在没有进一步确定所涉及的脑组织的细胞或亚细胞区室的情况下，无法确定这些变化的功能意义。
