Herisson Florence M, Brooks Lydia L, Waas Joseph R, Levine Allen S, Olszewski Pawel K
aDepartment of Biological Sciences, University of Waikato, Hamilton, New Zealand bDepartment of Food Science and Nutrition, University of Minnesota cMinnesota Obesity Center, St Paul, Minnesota, USA.
Neuroreport. 2014 Aug 20;25(12):909-14. doi: 10.1097/WNR.0000000000000201.
Centrally acting oxytocin (OT) inhibits feeding. Recent evidence suggests a link between OT and control of carbohydrate and saccharin intake, but it is unclear whether OT affects appetite for only carbohydrates, especially sweet ones, or sweet tastants irrespective of their carbohydrate content. Therefore, a blood-brain barrier penetrant OT receptor antagonist, L-368,899, was administered in mice and intake of liquid diets containing carbohydrates sucrose, glucose, fructose, polycose, or cornstarch (CS) or the noncarbohydrate, noncaloric sweetener saccharin was studied in episodic intake paradigms: one in which only one tastant was available and the other in which a choice between a carbohydrate (sucrose, glucose, or fructose) and saccharin was provided. We also used real-time PCR to examine hypothalamic Ot mRNA levels in mice provided short-term access to sucrose, CS, or saccharin. In the no-choice paradigm, L-368,899 increased the intake of all carbohydrates, whereas its effect on saccharin consumption showed only a trend. A 10 times lower dose (0.3 mg/kg) stimulated intake of sucrose than other carbohydrates. In the choice test, a very low 0.1 mg/kg dose of L-368,899 doubled the proportion of sucrose consumption relative to saccharin, but did not affect fructose or glucose preference. Ot gene expression increased after sucrose and CS, but not saccharin exposure compared with the controls; however, a higher level of significance was detected in the sucrose group. We conclude that OT inhibits appetite for carbohydrates. Sucrose consumption considerably enhances Ot gene expression and is particularly sensitive to OT receptor blockade, suggesting a special functional relationship between OT and sugar intake.
中枢作用的催产素（OT）会抑制进食。最近的证据表明OT与碳水化合物和糖精摄入的控制之间存在联系，但尚不清楚OT是否仅影响对碳水化合物（尤其是甜味碳水化合物）的食欲，还是影响不论碳水化合物含量的甜味剂的食欲。因此，给小鼠注射了一种可穿透血脑屏障的OT受体拮抗剂L-368,899，并在间歇性摄入模式下研究了其对含碳水化合物蔗糖、葡萄糖、果糖、多糖或玉米淀粉（CS）或非碳水化合物、无热量甜味剂糖精的流质饮食的摄入量：一种模式是仅提供一种味觉剂，另一种模式是在碳水化合物（蔗糖、葡萄糖或果糖）和糖精之间进行选择。我们还使用实时PCR检测了短期接触蔗糖、CS或糖精的小鼠下丘脑Ot mRNA水平。在无选择模式下，L-368,899增加了所有碳水化合物的摄入量，而其对糖精消耗的影响仅呈趋势性。低10倍的剂量（0.3mg/kg）刺激蔗糖摄入的效果比其他碳水化合物更明显。在选择试验中，极低剂量0.1mg/kg的L-368,899使蔗糖相对于糖精的消耗比例增加了一倍，但不影响对果糖或葡萄糖的偏好。与对照组相比，蔗糖和CS暴露后Ot基因表达增加，但糖精暴露后未增加；然而，在蔗糖组中检测到更高的显著性水平。我们得出结论，OT抑制对碳水化合物的食欲。蔗糖消耗显著增强Ot基因表达，并且对OT受体阻断特别敏感，这表明OT与糖摄入之间存在特殊的功能关系。
