Influence of betahistine repeated administration on a weight gain and selected metabolic parameters in the model of excessive eating in rats

Metabolic effects of a submaximal dose of pink salt and monosodium glutamate in experimental rats

Background & objectives

Pink salt and monosodium glutamate (MSG) are two typical food additives used in cooking to enhance flavour. However, excessive use of them has been associated to a variety of metabolic problems, including weight gain and hyperglycemia. The current study aimed to assess the metabolic changes caused by submaximal dosages of MSG and pink salt in experimental rats.

Methods

Twenty-four 120-150 g Wister rats of both sexes were divided into three groups: control, pink salt-treated (0.8 g/kg daily for three weeks), and MSG-treated (3.6 g/kg daily for three weeks). The body weight, amount of food and water consumed, and blood glucose levels of animals were measured and recorded as indicators of their metabolic changes. Furthermore, after salt treatments at intervals such as week 1, week 2, and week 3, the survival rate and general toxicity manifestations were determined. The results were statistically analysed using one-way ANOVA, with p < 0.05 being considered significant.

Results

The study found that the group given a submaximal dose of MSG gained significantly more weight (p < 0.05), consumed more food and water, and had higher blood glucose levels than the control. Ninety percent of the MSG therapy group survived by the end of the third week, however, they suffered from negative effects like abdominal distention, respiratory problems, ptosis, and subcutaneous swelling. On the other hand, the consumption of food and drink was significantly (p < 0.05) increased upon the administration of pink salt. Only little changes were observed in the body weight, blood sugar levels, and general features (such as subcutaneous swelling, change in bowel colour, and loose stools). Additionally, it was shown that the survival rate remained unchanged, particularly after week 3.

Conclusion

According to study findings, MSG may induce metabolic issues, increasing the chance of death. While there was no discernible metabolic aberration linked to pink salt. Further research is required to fully understand the mechanism and consequences of these taste enhancers on the host system before pink salt can be deemed safe.

KSK-74: Dual Histamine H3 and Sigma-2 Receptor Ligand with Anti-Obesity Potential

Many studies involving compounds that enhance histamine release, such as histamine H₃ receptor (H₃R) antagonists, have shown efficacy in inhibiting weight gain, but none have passed clinical trials. As part of the search for H₃ receptor ligands that have additional properties, the aim of this study is to evaluate the activity in the reduction in weight gain in a rat model of excessive eating, as well as the impact on selected metabolic parameters, and the number and size of adipocytes of two new H₃R antagonists, KSK-60 and KSK-74, which also exert a significant affinity at the sigma-2 receptor. Compounds KSK-60 and KSK-74 are homologues and the elongation of the distal part of the molecule resulted in an approximate two-fold reduction in affinity at H₃R, but simultaneously an almost two-fold increase in affinity at the sigma-2 receptor. Animals fed palatable feed and receiving KSK-60 or KSK-74 both at 10 mg/kg b.w. gained significantly less weight than animals in the control obese group. Moreover, KSK-74 significantly compensated for metabolic disturbances that accompany obesity, such as an increase in plasma triglyceride, resistin, and leptin levels; improved glucose tolerance; and protected experimental animals against adipocyte hypertrophy. Furthermore, KSK-74 inhibited the development of inflammation in obesity-exposed adipose tissue. The in vivo pharmacological activity of the tested ligands appears to correlate with the affinity at the sigma-2 receptors; however, the explanation of this phenomenon requires further and extended research.

Histamine H3 Receptor Ligands-KSK-59 and KSK-73-Reduce Body Weight Gain in a Rat Model of Excessive Eating

Noting the worldwide rapid increase in the prevalence of overweight and obesity new effective drugs are now being sought to combat these diseases. Histamine H₃ receptor antagonists may represent an effective therapy as they have been shown to modulate histamine synthesis and release and affect a number of other neurotransmitters (norepinephrine, acetylcholine, γ-aminobutyric acid, serotonin, substance P) thus influencing the food intake. Based on the preliminary studies determining affinity, intrinsic activity, and selected pharmacokinetic parameters, two histamine H₃ receptor ligands were selected. Female rats were fed palatable food for 28 days and simultaneously administered the tested compounds intraperitoneally (i.p.) at a dose of 10 or 1 mg/kg b.w./day. Weight was evaluated daily and calorie intake was evaluated once per week. The plasma levels of cholesterol, triglycerides, leptin, adiponectin, ghrelin, corticosterone, CRP and IL-6 were determined at the end of experiment. The glucose tolerance test was also performed. To exclude false positives, the effect of tested compounds on spontaneous activity was monitored during the treatment, as well as the amount of consumed kaolin clay was studied as a reflection of possible gastrointestinal disturbances comparable to nausea. The histamine H₃ receptor antagonists KSK-59 and KSK-73 administered i.p. at a dose of 10 mg/kg b.w. prevented weight gain in a rat model of excessive eating. They reduced adipose tissue deposits and improved glucose tolerance. Both compounds showed satisfying ability to penetrate through biological membranes determined in in vitro studies. Compound KSK-73 also reduced the caloric intake of the experimental animals what indicates its anorectic effect. These results show the pharmacological properties of histamine H₃ receptor antagonists, (4-pyridyl)piperazine derivatives, as the compounds causing not only slower weight gain but also ameliorating some metabolic disorders in rats having the opportunity to overeat.