Chronic nutritional deprivation of n-3 α-linolenic acid does not affect n-6 arachidonic acid recycling within brain phospholipids of awake rats
Chronic nutritional deprivation of n-3 α-linolenic acid does not affect n-6 arachidonic acid recycling within brain phospholipids of awake rats
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DOI：
10.1046/j.1471-4159.2001.00658.x
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发表时间：
2001-12-01
影响因子：
4.7
通讯作者：
Rapoport, SI
中科院分区：
文献类型：
--
作者：
Contreras, MA;Chang, MCJ;Rapoport, SI
使用体内脂肪酸模型和操作方程，我们报告了二十二碳六烯酸（DHA，22：6 n-3）的酯化和未酯化的浓度显着降低，在第三代（F3）大鼠的大脑中的营养剥夺的α-亚麻酸（18：3 n-3），和DHA的周转磷脂也减少。二十二碳五烯酸（DPA，22：5 n-6），花生四烯酸（AA，20：4 n-6）的延长/去饱和产物的浓度，几乎检测不到在对照组大鼠，但在剥夺大鼠升高。在本研究中，我们使用了相同的体内模型，包括静脉输注放射性标记的AA，以证明未酯化和酯化AA的浓度，以及磷脂内AA的周转率，与对照浓度相比，在清醒的F3代n-3缺陷大鼠的大脑中没有改变。脑DPA-CoA可以在剥夺而不是对照组大鼠中测量，并且AA-CoA在剥夺动物中升高。这些结果表明，AA和DHA在脑磷脂内相互独立地再循环，表明再循环分别由AA和DHA选择性酶独立调节。脑内n-3和n-6脂肪酸之间的竞争可能不会发生在再循环水平，但在延长抗去饱和水平（因此在n-3剥夺期间产生更多的DPA），或转化为生物活性类花生酸和其他代谢物。
Using an in vivo fatty acid model and operational equations, we reported that esterified and unesterified concentrations of docosahexaenoic acid (DHA, 22:6 n-3) were markedly reduced in brains of third-generation (F3) rats nutritionally deprived of a-linolenic acid (18:3 n-3), and that DHA turnover within phospholipids was reduced as well. The concentration of docosapentaenoic acid (DPA, 22 : 5 n-6), an arachidonic acid (AA, 20 : 4 n-6) elongation/desaturation product, was barely detectable in control rats but was elevated in the deprived rats. In the present study, we used the same in vivo model, involving the intravenous infusion of radio-labeled AA to demonstrate that concentrations of unesterified and esterified AA, and turnover of AA within phospholipids, were not altered in brains of awake F3-generation n-3-deficient rats, compared with control concentrations. Brain DPA-CoA could be measured in the deprived but not control rats, and AA-CoA was elevated in the deprived animals. These results indicated that AA and DHA are recycled within brain phospholipids independently of each other, suggesting that recycling is regulated independently by AA- and DHA-selective enzymes, respectively. Competition among n-3 and n-6 fatty acids within brain probably does not occur at the level of recycling, but at levels of elongation anti desaturation (hence greater production of DPA during n-3 deprivation), or conversion to bioactive eicosanoids and other metabolites.