Gene expression and neural circuit formation in the developing brain nuclei governing suckling and masticatory behavior.

1)神经肽Y (NPY) mRNA在发育中的控制摄食行为的脑核中的表达通过原位杂交检测出生后第2天至第10天发育中的控制摄食行为的脑核（PND2-10）中NPY mRNA的表达。在PND2、7和10时，禁食组下丘脑弓状核（ARC）中NPY mRNA的表达量显著高于对照组。在PND2时，禁食组与对照组相比，孤立束核NPY mRNA的表达有所增加，但在PND7和10时差异无统计学意义。空腹组小鼠腹腔注射胰岛素（5U/kg）或瘦素（2mg /kg）可降低小鼠ARC中NPY mRNA的表达。2)儿茶酚o -甲基转移酶（COMT） mRNA在新生儿下丘脑的表达及雌激素受体的影响下丘脑视交叉上核（SCN）在PND1和2的整个背侧区均有COMT mRNA的表达，直到PND16， COMT mRNA水平逐渐下降。COMT mRNA主要定位于SCN的腹侧和内侧。新生儿下丘脑COMT mRNA的表达可通过s.c.注射17β-雌二醇或双酚a而降低，而这些作用可通过联合使用选择性雌激素受体拮抗剂ICI182780而被阻断。3)软性食物和牙齿脱落对成年齿状回神经发生的影响4周龄小鼠分别饲喂粉饲10周，同时或不切除磨牙。14周龄每日注射溴脱氧尿嘧啶（BrdU），连续12天。注射BrdU 5周后，这些小鼠的BrdU阳性DG细胞数量比对照组减少更大，无磨牙小鼠的神经元与BrdU阳性细胞的比例下降。

1) Expression of neuropeptide Y (NPY) mRNA in the developing brain nuclei controlling feeding behaviorNPY mRNA expression was examined by in situ hybridization in the developing brain nuclei controlling feeding behavior from day 2 to day 10 of postnatal age (PND2-10). NPY mRNA expression in the hypothalamic arcuate nucleus (ARC) was significantly higher in fasted group than control group at PND2, 7 and 10. NPY mRNA expression in the nucleus of the solitary tract was increased in fasted group compared to control group at PND2 but there was no difference at PND7 and 10. NPY mRNA expression in the ARC of fasted group was reduced by a s.c. injection of insulin (5U/kg) or leptin (2 mg/kg).2) Catechol O-methyltransferase (COMT) mRNA expression in neonatal hypothalamus and an implication of estrogen receptorsCOMT mRNA expression was observed in the hypothalamic suprachiasmatic nucleus (SCN) throughout its rostrocaudal extent at PND1 and 2, and the mRNA levels decreased gradually until PND16. COMT mRNA was predominantly localized to the ventral and medial parts of the SCN. Neonatal COMT mRNA expression in the hypothalamus was reduced by a s.c. injection of 17β-estradiol or bisphenol A, and these effects were blocked by co-administration of ICI182780, a selective estrogen receptor antagonist.3) Effects of soft food and tooth-loss on neurogenesis in the adult dentate gyrus (DG)Four-week-old mice were subjected to feed powder diet for 10 weeks with or without removal of molars. They received daily injection of bromodeoxyuridine (BrdU) at 14 weeks of age for 12 consecutive days. BrdU-positive DG cells in these mice showed larger reduction in number than in control at 5 weeks after the BrdU injection and the ratio of neurons to the BrdU-positive cells decreased in the molarless mice.