Arai T, Wakabayashi S, Channing M A, Dunn B B, Der M G, Bell J M, Herscovitch P, Eckelman W C, Rapoport S I, Chang M C
Laboratory of Neurosciences, National Institutes on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
J Nucl Med. 1995 Dec;36(12):2261-7.
We determined regional incorporation coefficients (k*) of plasma [1-11C]palmitate into stable brain lipids of anesthetized monkeys with PET.
Carbon-11-palmitate was injected intravenously in untreated animals and in animals pretreated with methyl palmoxirate (MEP), an inhibitor of beta-oxidation of palmitate in the brain and periphery. Plasma radioactivity was followed, and brain radioactivity was determined at various times using PET. A least-squares method was used to fit the data to an operational equation to obtain regional values of k* and of cerebral blood volume (Vb) in individual experiments.
MEP significantly decreased the integral of plasma [11C]CO2 following 11C-palmitate infusion. Mean values of k* in monkeys not given MEP were 4.9, 4.2, 4.9, 4.0 and 2.9 x 10(-5) ml/sec.g for the temporal, frontal, parietal and occipital cortices and white matter, respectively. With the exception of k* in white matter, which was increased by MEP, k* in the other brain regions was not significantly changed by MEP. The Vb ranged from 0.035 ml/g to 0.048 ml/g in gray matter regions and equaled 0.022 ml/g in white matter.
PET can be used to determine regional incorporation coefficients of 11C-palmitate into the primate brain in vivo. Combined with MEP, 11C-palmitate could be used with PET to examine regional brain phospholipid metabolism in humans in normal and pathological conditions.
我们使用正电子发射断层扫描（PET）测定了麻醉猴血浆中[1-11C]棕榈酸酯在稳定脑脂质中的区域掺入系数（k*）。
将碳-11-棕榈酸酯静脉注射到未经处理的动物以及用甲基棕榈酰肉碱（MEP）预处理的动物体内，MEP是脑和外周中棕榈酸酯β氧化的抑制剂。追踪血浆放射性，并使用PET在不同时间测定脑放射性。在各个实验中，使用最小二乘法将数据拟合到一个运算方程，以获得k*和脑血容量（Vb）的区域值。
MEP显著降低了11C-棕榈酸酯输注后血浆[11C]CO2的积分。未给予MEP的猴子中，颞叶、额叶、顶叶和枕叶皮质以及白质的k平均值分别为4.9、4.2、4.9、4.0和2.9×10^(-5) ml/sec·g。除白质中的k因MEP而增加外，MEP对其他脑区的k*没有显著影响。灰质区域的Vb范围为0.035 ml/g至0.048 ml/g，白质中的Vb为0.022 ml/g。
PET可用于在体内测定11C-棕榈酸酯在灵长类动物脑中的区域掺入系数。结合MEP，11C-棕榈酸酯可与PET一起用于检查正常和病理条件下人类的区域脑磷脂代谢。
