Evidence that Release of Dopamine in the Brain is Involved in the Inhibitory Effect of Cholecystokinin Octapeptide on Ingestion of Intraorally Administered Sucrose in Male Rats

To study the possibility that release of dopamine in the brain mediates the inhibitory effect of Cholecystokinin octapeptide on ingestive behaviour, the effect of amphetamine on intake of pellets or an intraorally administered sucrose solution was compared with that of Cholecystokinin octapeptide. Additionally, comparisons were made between the effect of Cholecystokinin octapeptide and pargyline, a monoamine oxidase inhibitor, and α-methyl-ρ-tyrosine, a tyrosine hydroxylase inhibitor. While amphetamine dose-dependently inhibited pellet intake it failed to inhibit sucrose intake in doses which caused behavioural stereotypies (<800 μg). Cholecystokinin octapeptide (5 μg) inhibited ingestive behaviour in both tests. A very high dose of amphetamine (2 mg) was required to inhibit sucrose intake to a level comparable to that of Cholecystokinin octapeptide. Pargyline (5 to 25 mg) or α-methyl-p-tyrosine (25 to 100 mg) dose-dependently inhibited pellet intake but had only weak effects on the intake of sucrose. Pargyline increased the concentration of dopamine and 3-methoxytyramine in the dorsal striatum and decreased the concentration of 3,4-dihydroxyphenylacetic acid. α-Methyl-ρ-tyrosine decreased the concentration of dopamine and 3,4-dihydroxyphenylacetic acid, but not that of 3-methoxytyramine. Injection of amphetamine (2 mg), but not Cholecystokinin octapeptide, in rats pretreated with pargyline increased the concentration of 3-methoxytyramine in the dorsal striatum and this effect was blocked by pretreatment with α-methyl-ρ-tyrosine. Pretreatment with α-methyl-ρ-tyrosine partially reversed the inhibitory effect of Cholecystokinin octapeptide on sucrose ingestion, enhanced the effect of amphetamine but did not affect that of apomorphine, a dopamine agonist. The results support the possibility that the inhibitory effect of Cholecystokinin octapeptide on consummatory ingestive behaviour, in part, is mediated via release of dopamine in the brain.     

甘油蔗糖液对哺乳动物桑椹胚的渗透反应及冻存效果研究

为了提供快速冷冻前胚胎发生部分脱水的科学依据，我们观察了家兔桑椹胚在冷冻保护液中的体积变化。当桑椹胚置于仅含３．０ｍｏｌ／Ｌ或４．０ｍｏｌ／Ｌ甘油液中，桑椹胚立即皱缩，２ｍｉｎ时体积为等渗时体积的５８．９％或５９．６＾％，１０ｍｉｎ时桑椹胚体积达到等渗量的９０．８％或７６．９％，将这些桑椹胚接着移入含３．０ｍｏｌ／Ｌ或４．０ｍｏｌ／Ｌ甘油加０．２５ｍｏｌ／Ｌ蔗糖保护液中，桑椹胚再次发生皱缩主膨大变     

The effects of sucrose on stability of human brain natriuretic peptide [hBNP (1–32)] and human parathyroid hormone [hPTH (1–34)]

Abstract: Although the effect of sucrose on the physical stability of proteins has been well documented, its impact on their chemical stability is largely unknown. The aim of this study was to investigate the potential effects of sucrose on the structural conformation of human brain natriuretic peptide [hBNP (1–32)] and the synthetic human parathyroid hormone [hPTH (1–34)], and link these effects to chemical degradation pathways of these peptides. The stability of hBNP (1–32) and hPTH (1–34) was studied at pH 5.5. Aggregation was monitored using size exclusion high‐performance liquid chromatography (SE‐HPLC), whereas oxidation and deamidation products were measured by reversed phase (RP) HPLC. Fourier transform infrared (FT‐IR) spectroscopy was used to study the peptides’ conformation. Sucrose retarded aggregation, deamidation, and oxidation of hBNP (1–32) and hPTH (1–34), with a maximum effect at relatively high concentrations (as much as 1 m ). FT‐IR spectroscopy indicated that sucrose maintained the native conformation of hBNP (1–32) and induced small conformation changes in the hPTH (1–34) structure. Sucrose enhanced the stability of hBNP (1–32) and hPTH (1–34) in liquid formulations. The stabilizing effect of sucrose was due to a large extent to retardation of oxidation and deamidation of hBNP (1–32) and hPTH (1–34).     

远志的化学成分研究Ⅱ

目的 :研究远志的化学成分。方法 :采用多种色谱方法进行分离 ,利用光谱数据结合理化分析进行结构鉴定。结果 :从远志根皮的正丁醇层中分离得到 4个蔗糖酯类化合物 ,分别鉴定为 :sibiricoseA₅(1) ,sibiricoseA₆(2 ) ,tenuifolisideA(3)和 3′ ,6 disinapoylsucrose(4 )。结论 :化合物 1和 2为首次从该植物中分离得到。     

Low and High Field Magnetic Resonance for in Vivo Analysis of Seeds

Low field NMR has been successfully used for the evaluation of seed composition and quality, but largely only in crop species. We show here that 1.5T NMR provides a reliable means for analysing the seed lipid fraction present in a wide range of species, where both the seed size and lipid concentration differed by >10 fold. Little use of high field NMR has been made in seed research to date, even though it potentially offers many opportunities for studying seed development, metabolism and storage. Here we demonstrate how 17.5T and 20T NMR can be applied to image seed structure, and analyse lipid and metabolite distribution. We suggest that further technical developments in NMR/MRI will facilitate significant advances in our understanding of seed biology.     

Fructose-Containing Sugars and Cardiovascular Disease

Cardiovascular disease (CVD) is the single largest cause of mortality in the United States and worldwide. Numerous risk factors have been identified for CVD, including a number of nutritional factors. Recently, attention has been focused on fructose-containing sugars and their putative link to risk factors for CVD. In this review, we focus on recent studies related to sugar consumption and cardiovascular risk factors including lipids, blood pressure, obesity, insulin resistance, diabetes, and the metabolic syndrome. We then examine the scientific basis for competing recommendations for sugar intake. We conclude that although it appears prudent to avoid excessive consumption of fructose-containing sugars, levels within the normal range of human consumption are not uniquely related to CVD risk factors with the exception of triglycerides, which may rise when simple sugars exceed 20% of energy per day, particularly in hypercaloric settings.     

The effect of maternal caffeine ingestion on pancreatic function in the neonatal rat

Summary Pancreatic function was investigated in neonatal suckling offspring of caffeine-ingesting dams, with or without maternal sucrose supplementation, throughout pregnancy and lactation. In offspring of rats ingesting caffeine without sucrose supplementation, there was initial hyperinsulinaemia, followed by a progressive fall of plasma insulin to subnormal levels. This fall in plasma insulin coincided with depletion of pancreatic insulin stores. Both the fall in plasma insulin and depletion of pancreatic insulin stores were prevented by sucrose supplementation of caffeine-ingesting dams. Offspring of dams fed sucrose alone and control offspring also maintained pancreatic insulin stores and circulating insulin levels over the first 14 days of postnatal life. Pancreases from offspring of caffeine-exposed animals tested in vitro showed enhanced sensitivity of the insulin release process to glucose. This was reflected in the glucose concentration required to elicit half-maximal insulin release (2.4 ± 0.2 mmol/l for caffeine offspring, 2.3 ± 0.2 mmol/l for caffeine with sucrose, 3.8 ± 0.3 mmol/l for sucrose and 4.1 ± 0.3 mmol/l for control offspring, mean ± SEM). In contrast, offspring of sucrose-supplemented (with or without caffeine) dams showed increased sensitivity of the proinsulin biosynthetic process to glucose, whereas offspring of dams ingesting caffeine alone showed no significant enhancement of the biosynthetic process compared with control offspring. Thus enhanced sensitivity of the insulin secretory process to glucose without a change in the sensitivity of the biosynthetic process in the offspring of the caffeine ingesting (nonsucrose supplemented) dams could explain the progressive depletion of pancreatic insulin stores and eventual hypoinsulinaemia seen in this group.