Otero-Rodiño Cristina, Librán-Pérez Marta, Velasco Cristina, Álvarez-Otero Rosa, López-Patiño Marcos A, Míguez Jesús M, Soengas José L
Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Edificio de Ciencias Experimentais, Universidade de Vigo, 36310, Vigo, Spain.
J Comp Physiol B. 2015 Dec;185(8):869-82. doi: 10.1007/s00360-015-0932-6. Epub 2015 Sep 30.
There is no evidence in fish brain demonstrating the existence of changes in lactate metabolism in response to alterations in glucose levels. We induced in rainbow trout through intraperitoneal (IP) treatments, hypoglycaemic or hyperglycaemic changes to assess the response of parameters involved in lactate metabolism in glucosensing areas like hypothalamus and hindbrain. To distinguish those effects from those induced by peripheral changes in the levels of metabolites or hormones, we also carried out intracerebroventricular (ICV) treatments with 2-deoxy-D-glucose (2-DG, a non-metabolizable glucose analogue thus inducing local glucopenia) or glucose. Finally, we also incubated hypothalamus and hindbrain in vitro in the presence of increased glucose concentrations. The changes in glucose availability were in general correlated to changes in the amount of lactate in both areas. However, when we assessed in these areas the response of parameters related to lactate metabolism, the results obtained were contradictory. The increase in glucose levels did not produce in general the expected changes in those pathways with only a minor increase in their capacity of lactate production. The decrease in glucose levels was, however, more clearly related to a decreased capacity of the pathways involved in the production and use of lactate, and this was especially evident after ICV treatment with 2-DG in both areas. In conclusion, the present results while addressing the existence of changes in lactate metabolism after inducing changes in glucose levels in brain glucosensing areas only partially support the possible existence of an astrocyte-neuron lactate shuttle in hypothalamus and hindbrain of rainbow trout relating glucose availability to lactate production and use.
没有证据表明鱼类大脑中存在乳酸代谢随葡萄糖水平变化而改变的情况。我们通过腹腔注射（IP）对虹鳟鱼进行低血糖或高血糖处理，以评估下丘脑和后脑等葡萄糖感应区域中参与乳酸代谢的参数的反应。为了将这些影响与代谢物或激素水平的外周变化所诱导的影响区分开来，我们还使用2-脱氧-D-葡萄糖（2-DG，一种不可代谢的葡萄糖类似物，从而诱导局部低血糖）或葡萄糖进行脑室内（ICV）处理。最后，我们还在葡萄糖浓度升高的情况下对下丘脑和后脑进行体外培养。葡萄糖可用性的变化总体上与这两个区域中乳酸量的变化相关。然而，当我们在这些区域评估与乳酸代谢相关的参数的反应时，获得的结果相互矛盾。葡萄糖水平的升高通常不会在那些途径中产生预期的变化，其乳酸产生能力仅略有增加。然而，葡萄糖水平的降低与参与乳酸产生和利用的途径的能力下降更明显相关，这在两个区域用2-DG进行ICV处理后尤其明显。总之，本研究结果在探讨大脑葡萄糖感应区域葡萄糖水平变化后乳酸代谢变化的存在时，仅部分支持虹鳟鱼下丘脑和后脑可能存在将葡萄糖可用性与乳酸产生和利用联系起来的星形胶质细胞-神经元乳酸穿梭。
