科学家发现，当遇到脑外伤（TBI）的小鼠食用富含支链氨基酸的饮食的时候，它们比对照组小鼠的认知恢复更好。TBI常常会破坏边缘系统的海马区，该区域参与了学习与记忆，而且脑损伤会导致特定神经元网络活动的改变，在一些区域触发更多的活动，而导致另一些区域活动更少。这种损伤还常常导致支链氨基酸（BCAAs）浓度的下降，BCAAs是制造基于谷氨酸的神经递质（大脑通讯的媒介）的关键成分。
Akiva Cohen及其同事提出，食用BCAA可能有助于恢复被改变的神经递质库，而且可能有助于大脑在经历脑损伤（如那些与运动有关的脑震荡带来的损伤）之后恢复其正常功能。这些科学家报告说，BCAA饮食补充剂可能成为TBI患者的一种疗法，尽管尚不清楚这种治疗对于TBI在几周或几个月之后才显示出来的影响是否有效。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS December 7, 2009, doi: 10.1073/pnas.0910280107
Dietary branched chain amino acids ameliorate injury-induced cognitive impairment
Jeffrey T. Colea,1, Christina M. Mitalaa, Suhali Kundua, Ajay Vermab, Jaclynn A. Elkindc, Itzhak Nissimd,e,f and Akiva S. Cohena,c,e,g,2
aDivision of Neurology
dChild Development, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
bDepartment of Neurology and Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
Departments of cNeurosurgery
ePediatrics
fBiochemistry and Biophysics
gNeurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
Neurological dysfunction caused by traumatic brain injury results in profound changes in net synaptic efficacy, leading to impaired cognition. Because excitability is directly controlled by the balance of excitatory and inhibitory activity, underlying mechanisms causing these changes were investigated using lateral fluid percussion brain injury in mice. Although injury-induced shifts in net synaptic efficacy were not accompanied by changes in hippocampal glutamate and GABA levels, significant reductions were seen in the concentration of branched chain amino acids (BCAAs), which are key precursors to de novo glutamate synthesis. Dietary consumption of BCAAs restored hippocampal BCAA concentrations to normal, reversed injury-induced shifts in net synaptic efficacy, and led to reinstatement of cognitive performance after concussive brain injury. All brain-injured mice that consumed BCAAs demonstrated cognitive improvement with a simultaneous restoration in net synaptic efficacy. Posttraumatic changes in the expression of cytosolic branched chain aminotransferase, branched chain ketoacid dehydrogenase, glutamate dehydrogenase, and glutamic acid decarboxylase support a perturbation of BCAA and neurotransmitter metabolism. Ex vivo application of BCAAs to hippocampal slices from injured animals restored posttraumatic regional shifts in net synaptic efficacy as measured by field excitatory postsynaptic potentials. These results suggest that dietary BCAA intervention could promote cognitive improvement by restoring hippocampal function after a traumatic brain injury.
