Klockars Oscar A, Klockars Anica, Levine Allen S, Olszewski Pawel K
Department of Biological Sciences, University of Waikato, Hamilton, New Zealand.
Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA.
Neuroreport. 2018 Apr 11;29(6):504-510. doi: 10.1097/WNR.0000000000001005.
Oxytocin (OT) at acting central nuclei decreases meal size and reduces intake of palatable sweet solutions. It remains largely unclear as to which brain sites mediate OT's effect on palatability versus energy or the combination of those aspects of consumption. Here, we expanded the search for sites that mediate anorexigenic properties of OT by focusing on two subdivisions of the amygdala, its central (CNA) and basolateral (BLA) nuclei. We injected OT directly into the BLA or CNA in rats and assessed intake of standard chow induced by energy deprivation and intake of sweet solutions in nondeprived animals. We examined whether these effects are reversible by OT receptor (OTr) antagonism and whether OT presence in BLA or CNA induces taste aversion. We also determined the effect of energy deprivation and exposure to sweet saccharin on BLA and CNA expression of OTr mRNA. OT administration in BLA at 0.3 μg and in CNA at 1 μg reduced standard chow intake after deprivation by ~25%. Only administration of OT in BLA was effective in suppressing consumption of sucrose and saccharin solutions. The anorexigenic effects of OT in BLA and CNA were attenuated by OTr antagonist, L-368,899, pretreatment. OT at anorexigenic doses did not promote acquisition of taste aversion. BLA OTr mRNA expression was affected by exposure to palatable saccharin, whereas that of CNA OTr, by energy deprivation. OT in the amygdala moderately decreases food intake. The functional relationship between amygdalar OT and energy intake versus palatability-driven intake depends on the discrete localization of the OTr within this complex structure.
作用于中枢核团的催产素（OT）可减少进食量并降低对美味甜味溶液的摄入量。目前仍不清楚是哪些脑区介导了OT对适口性与能量的影响，还是介导了这些消费方面的综合影响。在这里，我们通过聚焦杏仁核的两个亚区，即中央核（CNA）和基底外侧核（BLA），扩大了对介导OT厌食特性的脑区的搜索。我们将OT直接注射到大鼠的BLA或CNA中，并评估能量剥夺诱导的标准食物摄入量以及非剥夺动物对甜味溶液的摄入量。我们研究了OT受体（OTr）拮抗剂是否能逆转这些效应，以及BLA或CNA中存在OT是否会诱发味觉厌恶。我们还确定了能量剥夺和接触甜味糖精对BLA和CNA中OTr mRNA表达的影响。在BLA中注射0.3μg的OT和在CNA中注射1μg的OT可使剥夺后标准食物摄入量减少约25%。只有在BLA中注射OT才能有效抑制蔗糖和糖精溶液的消耗。OTr拮抗剂L-368,899预处理可减弱OT在BLA和CNA中的厌食作用。厌食剂量的OT不会促进味觉厌恶的形成。接触美味糖精会影响BLA中OTr mRNA的表达，而能量剥夺会影响CNA中OTr mRNA的表达。杏仁核中的OT适度减少食物摄入量。杏仁核OT与能量摄入和适口性驱动的摄入之间的功能关系取决于OTr在这个复杂结构中的离散定位。
