Effect of short-term intake of four sweeteners on feed intake, solution consumption and neurotransmitters release on mice.

This study focused on the effect of short-term intake of sweeteners on feed intake, solution consumption and neurotransmitters release on mice. The results showed that the free drinking of 10 mM sucralose solution, 100 mM maltose solution, 3 mM saccharin solution and 3 g/L stevioside solution for 32 days will not affect the normal development of the body weight and feed intake of the mice. The consumption of maltose solution was significantly higher than that of the other sweeteners. The leptin and insulin levels increased significantly after the short-term intake of these four sweeteners. The dopamine (DA) content in the whole brain of the mice increased significantly only in the maltose group. These results indicate that the short-term intake of the preferred concentrations of maltose, stevioside, sucralose and saccharin will not affect the body weight and feed intake of the mice. Mice prefer maltose solution to other sweeteners solutions. The 100 mM maltose solution and 3 mM saccharin solution could result in the oxidative stress on mice after 32 days' short-term intake. Compared with other sweeteners, only sugars that could be broken down into small molecules of glucose might have a positive effect on dopamine levels.

Effect and mechanism of high-fat diet on the preference for sweeteners on mice.

BACKGROUND: Male Kunming mice were divided into a normal diet group (control group) and a high-fat diet group (HF group) (185 g·kg-1 protein, 600 g·kg-1 fat and 205 g·kg-1 carbohydrate). After 8 weeks' feeding, behavioral indicators and biochemical indicators in serum were determined. The double-bottle preference experiment was used to study the preferences of mice for five sweeteners. The monoamine neurotransmitter content, gene expression related to dopamine (DA), and opioid receptors were also determined. RESULTS: The body weight of the mice in the HF group increased significantly (P < 0.05) after 36 days compared with the control group. The feed intake of the HF group increased sharply in the first 12 days, and then it became basically unchanged. The preference of the HF group for all of the five sweeteners was highly significantly lower (P < 0.01) than that of the control group. Depression-related behavior was observed in the HF group mice. The triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDLC) content in the HF group were very much higher (P < 0.01) than those of the control group. The gene expression related to DA and opioid receptor in the HF group was significantly lower than that of the control group, except for preproenkephalin (PENK). CONCLUSIONS: In summary, this study suggested that a long-term high-fat diet could result in a decrease in the preference for sweeteners and could result in a state of reward hypofunction in mice. © 2020 Society of Chemical Industry.

Effect of short-term intake of high- and low-concentrations of sucrose solution on the neurochemistry of male and female mice.

The effect of short-term intake of high- and low-concentrations of sucrose solution on the neurochemistry of male and female mice was studied. The body weight, feed intake, sucrose solution consumption and brain monoamine neurotransmitters were determined after 34 days' intake of 1% and 8% sucrose solutions. The gene expression and protein levels related to dopamine and opioids were also determined. The results showed that the intake of 1% and 8% sucrose solution for 34 days did not cause significant changes in the weight development of both male and female mice. The preference for sucrose varies with sex. Both males and females had greater preference for the high concentration sucrose solution than the low concentration sucrose solution. The continuous intake of sucrose stimulated the release of monoamine neurotransmitters (DA, 5-HT, NE) in the brains of mice, and the reward effect of 8% sucrose solution is significantly higher than that of 1% sucrose solution. The sex of mice did not affect the release of neurotransmitters. The gene expressions of D1 and D2 were up-regulated in the 1% sucrose group of male mice, while the OPRM1 gene expression was down-regulated. The expression of these three genes in the 8% sucrose group of male mice was all down-regulated, while the gene expressions of D1 and D2 in the 1% and 8% sucrose group (p < 0.05) of female mice were both up-regulated.

Effects of different sweeteners on behavior and neurotransmitters release in mice.

Four natural sweeteners (sucrose, stevioside, maltose and xylitol) and six artificial sweeteners (acesulfame, sucralose, aspartame, cyclamate, saccharin and neotame) were used to study the effects of different sweeteners on the behavior and neurotransmitter release of mice with two-bottle preference experiments. The results showed that very significant preference behavior for 8% sucrose solution, 0.3% stevioside solution, 10 mM acesulfame, 10 mM sucralose and 10 mM aspartame solutions (p < 0.01) was observed on mice. Long-term exposure of sucrose solution and acesulfame solution can affect the behavioral indicators such as solution consumption, feed intake, body weight and the release of neurotransmitters in mice. The solution consumption and the release of neurotransmitters were significantly greater (p < 0.05) than that of the control group (water group), but there was no significant difference in feed intake. The acesulfame-A and acesulfame-B groups had no significant difference on the consumption of solution and feed intake, but there was significant difference in the release of neurotransmitters. The result also showed that different sweetener solutions with similar sweetness had the same effect on the neurotransmitters release, and it can be inferred that mice have an addictive behavioral characteristic to sucrose.

Antidepressant-like Effect of Citrus sinensis (L.) Osbeck Essential Oil and Its Main Component Limonene on Mice.

The present study investigated the antidepressant-like effects of navel orange [Citrus sinensis (L.) Osbeck] essential oil (OEO) and its main components using the chronic unpredictable mild stress (CUMS) model mice and explored its possible mechanisms. The results indicated that OEO inhalation significantly ameliorated the depression-like behaviors of CUMS mice with decreased body weight, sucrose preference, curiosity, and mobility as well as shortened immobile time and attenuated dyslipidemia. Limonene was the most abundant compound in the sniffing OEO environment and mice brain after sniffing, and it was not metabolized immediately in the brain. In addition, limonene inhalation significantly restored CUMS-induced depressive behavior, hyperactivity of hypothalamic-pituitary-adrenal axis, and the decrease of monoamine neurotransmitter levels, with downregulation of brain-derived neurotrophic factor and its receptor expression in the hippocampus. Thus, the study indicates that the improvements in neuroendocrine, neurotrophic, and monoaminergic systems are related to the antidepressant effects of limonene.