Noronha J G, Larson D M, Rapoport S I
Laboratory of Neurosciences, National Institute on Aging, Bethesda, Maryland 20892.
Exp Neurol. 1989 Mar;103(3):267-76. doi: 10.1016/0014-4886(89)90050-2.
Regional rates of incorporation into brain of intravenously administered [14C]palmitate and regional cerebral metabolic rates for glucose (rCMRglc) were measured in water-provided (WP) and water-deprived (WD) homozygous (DI) and heterozygous (HZ) Brattleboro rats, a mutant strain unable to synthesize vasopressin, and in the parent Long-Evans (LE) strain. Following 15 h or 4 days of water deprivation, rCMRglc was elevated threefold in the pituitary neural lobe of LE-WD and DI-WD as compared with LE-WP rats, and in the paraventricular nucleus of LE-WD, and the supraoptic nucleus of DI-WD rats. However, incorporation of [14C]palmitate into these regions was not specifically altered. The results indicate that water deprivation for up to 4 days increases rCMRglc in some brain regions involved with vasopressin, but does not alter [14C]palmitate incorporation into these regions. Incorporation of plasma [14C]palmitate is independent of unlabeled plasma palmitate at brain regions which have an intact blood-brain barrier, but at nonbarrier regions falls according to saturation kinetics as cold plasma concentration rises, with a mean half-saturation constant (Km) equal to 0.136 mumol.ml-1.
在供水充足（WP）和缺水（WD）的纯合子（DI）和杂合子（HZ）Brattleboro大鼠（一种无法合成血管加压素的突变品系）以及亲代Long-Evans（LE）品系大鼠中，测量了静脉注射[14C]棕榈酸酯进入大脑的区域速率以及葡萄糖的区域脑代谢率（rCMRglc）。在缺水15小时或4天后，与LE-WP大鼠相比，LE-WD和DI-WD大鼠的垂体神经叶、LE-WD大鼠的室旁核以及DI-WD大鼠的视上核中的rCMRglc升高了三倍。然而，[14C]棕榈酸酯在这些区域的掺入并没有特异性改变。结果表明，长达4天的缺水会增加一些与血管加压素相关的脑区的rCMRglc，但不会改变[14C]棕榈酸酯在这些区域的掺入。在具有完整血脑屏障的脑区，血浆[14C]棕榈酸酯的掺入独立于未标记的血浆棕榈酸酯，但在非屏障区域，随着冷血浆浓度的升高，其掺入量根据饱和动力学下降，平均半饱和常数（Km）等于0.136 μmol.ml-1。
