A search for effective components of food flavor that stimulate energy expenditure and the analysis of its neuro-hormonal mechanism

本研究的目的是(1)探索和鉴定食物风味中刺激体内能量消耗的有效成分，以及(2)通过分析全身耗氧量(VO2)和呼吸商(RQ)来阐明调节食物摄入的中枢作用神经肽对能量消耗的作用。1.在第一类研究中，我们考察了生姜和树莓及其有效成分姜酮和树莓酮对高碳水化合物饮食和高脂肪饮食大鼠VO2和RQ的影响。两种饲料中添加2%姜粉或0.4%姜酮均能显著提高暗摄食期12小时的累积VO2。在此期间，添加生姜或姜酮显著降低了RQ值。同样，在两种饲料中添加0.4~5%的树莓酮，可引起累积VO2的剂量依赖性增加和RQ值的降低。此外，在高脂饲料中添加树莓酮，可防止脂肪组织和肝脏中甘油三酯的蓄积，改善高脂饲料喂养4周大鼠的脂代谢紊乱。2.在促氧物质中，向大鼠第三脑室注入食欲素-A可显著增加VO2，而去甲肾上腺素(NA)则降低VO2。脑室微量注射神经肽Y和Ghrelin使RQ值增加，NA引起RQ值一过性降低。然而，中枢注射甘丙肽、食欲素B或黑素浓缩激素对VO2和RQ值均无显著影响。另一方面，在厌食性神经肽中，瘦素引起RQ下降，但对暗期间的累积VO2没有显著影响。相比之下，微量注射促肾上腺皮质激素释放激素可降低RQ，增加累积VO2。

The object of this study was to (1)explore and identify effective components of food flavor that stimulates energy expenditure in the body, and (2)to elucidate the actions of centrally-acting neuropeptides that regulate food intake on energy expenditure by analyzing whole-body oxygen consumption (VO2) and the respiratory quotient(RQ).1.On the first category of the studies, we examined the effects of ginger and raspberry and their effective components, zingerone and raspberry ketone, on VO2 and RQ in rats fed a high-carbohydrate diet or a high-fat(lard) diet. Addition of 2% ginger powder or 0.4% zingerone to both diets caused significant increase in 12-h cumulative VO2 during the dark(feeding) period. The RQ value during the period was reduced significantly by the addition of ginger or zingerone. Similarly, addition of 0.4〜5% raspberry ketone to the both diets caused dose-dependent increases in the cumulative VO2 and decreases in the RQ values. In addition, addition of raspberry ketone to the high-fat diet prevented the accumulation of triglycerides in adipose tissues and liver, and amended disorder of lipid metabolism induced in rats fed the high-fat diet for 4 weeks.2.Among orexigenic substances, orexin-A administered into the third ventricle of rats caused a marked increase in VO2, but conversely noradrenaline(NA) decreased VO2. transiently Intracerebroventricular microinjection of neuropeptide Y and ghrelin increased the RQ values, but NA caused transient decrease in the RQ. However, central injection of galanin, orexin-B, or melanin-concentrating hormone did not affect both the VO2 and RQ values significantly.Among anorexigenic neuropeptides, on the other hand, leptin caused a decrease in RQ but did not affect significantly the cumulative VO2 during the dark period By contrast, microinjection of corticotropin-releasing hormone was found to reduce RQ and increase the cumulative VO2.