Effect of the preweaning nutritional state on the cardiac protein profile and functional performance of the rat heart

The aim of the study was to find out whether the changes in nutritional status induced by different litter size during early postnatal development can influence quantitative and qualitative protein remodeling and contractile performance of the myocardium. Male Wistar rats born at the same day were pooled together at 2 days postbirth and assigned by random selection to dams in groups of 4, 8 or 16 rats/litter. The animals were investigated at the age of 4 and 16 weeks. The results revealed that the early postnatal nutritional modification altered weight parameters: whereas lower heart weight persisted in slow-growing rats until 16 weeks, higher body weight of fast-growing rats returned to the control level at the age of 16 weeks. Altered nutritional status influenced also protein remodeling of the myocardium: the concentration of all noncollagenous proteins (fractions of metabolic and contractile proteins) significantly increased in slow-growing rats, on the other hand, the concentration of collagenous proteins (pepsin-soluble and -insoluble fractions) was higher in fast-growing animals. The changes were, however, only transitional: three months after the end of the weaning period most protein changes returned to the control level. However, higher concentration of total blood lipids and triglycerides in fast-growing rats persisted until adulthood. Nutritional changes had, however, only minor effect on ventricular performance. No differences among groups were observed in basal values of the left ventricular pressure, while the maximum pressure attained after an acute ventricular loading and the contractile reserve were significantly decreased in slowgrowing 4 week old rats. The functional consequence of altered nutritional status during weaning was only transitional, in agreement with the transient character of most structural and biochemical markers of myocardial remodeling.     

基于Morris 水迷宫探讨不同贮食行为鼠类的空间记忆

鼠类的贮食方式(分散或集中)与其空间记忆能力有关,但有关两者的定量关系尚缺少实验证据。朝鲜姬鼠(Apodemus peninsulae)分散或集中贮藏食物;社鼠(Niviventer confucianus)、黑线姬鼠(A. agrarius)、昆明小鼠(Mus musculus)仅集中贮藏食物。利用Morris 水迷宫对4 种鼠的空间记忆能力进行了评估,以探讨其空间记忆能力与食物贮藏方式间的联系。结果发现:在5 d 的定位航行实验中,4 种鼠找到隐藏平台的潜伏期均呈现出显著的下降趋势,其中朝鲜姬鼠潜伏期最短,黑线姬鼠与社鼠次之,昆明小鼠最长。在空间探索实验中,朝鲜姬鼠、黑线姬鼠和社鼠穿越平台的次数显著大于昆明小鼠;实验鼠在目标象限内的时间比和路程比为:朝鲜姬鼠> 黑线姬鼠> 社鼠>昆明小鼠,但差异不显著。结果表明具有分散贮藏行为的朝鲜姬鼠的空间记忆能力较仅具有集中贮藏行为的其它鼠种强,暗示鼠类的食物贮藏方式与其空间记忆能力有一定联系。     

Effect of food intake on myocardial performance index

Background

Myocardial performance index (MPI) has been investigated in a variety of populations, but the effect of food intake has not been evaluated. We assessed whether myocardial performance index is affected by food intake in healthy subjects.

Methods

Twenty-three healthy subjects aged 25.6?±?4.5 years were investigated. MPI was measured before, 30 min after, and 110 min after a standardized meal.

Results

MPI decreased significantly (P?<?0.05) from fasting values 30 min after the meal, and had almost returned to baseline after 110 min. MPI decreased from 0.28?±?0.06 (fasting) to 0.20?±?0.07 30 min after eating. At 110 min after eating the index value was almost back to the baseline value 0.26?±?0.06. (P?=?0.15).

Conclusions

This study shows that myocardial performance index is affected by food intake in healthy subjects.

     

Effect of food intake on left ventricular wall stress

Objective

Left ventricular wall stress has been investigated in a variety of populations, but the effect of food intake has not been evaluated. We assessed whether left ventricular wall stress is affected by food intake in healthy subjects.

Methods

Twenty-three healthy subjects aged 25.6?±?4.5 years were investigated. Meridional end-systolic wall stress (ESS) and circumferential end-systolic wall stress (cESS) were measured before, 30 minutes after, and 110 minutes after a standardised meal.

Results

Both ESS and cESS decreased significantly (P?<?0.001) from fasting values 30 minutes after the meal, and had not returned to baseline after 110 minutes. ESS decreased from 65?±?16 kdynes/cm² (fasting) to 44?±?12 kdynes/cm² 30 minutes after, and to 58?±?13 kdynes/cm² 110 minutes after eating. cESS decreased from 98?±?24 kdynes/cm² to 67?±?18 kdynes/cm² 30 minutes after, and to 87?±?19 kdynes/cm² 110 minutes after the meal.

Conclusion

This study shows that left ventricular wall stress is affected by food intake in healthy subjects.     

Effect of changes in scrotal temperature on food intake in pigs

1. Temperature of the scrotum or a similarly sized area of skin on the back of young pigs was changed by means of a thermal pad and food intake was measured. 2. Warming the scrotum to 42 degrees C significantly increased food intake in pigs reared and fed at 25 degrees C. 3. Cooling the scrotum to 20 degrees C, or changing the back skin temperature had no effect on food intake. 4. Acclimation to 10 degrees C, or exposure to 10 degrees C for 4 hr before a meal resulted in an increase in food intake. 5. Warming the scrotum did not affect this cold-induced increase in food intake. Warming the scrotum, but not the skin on the back, reversed the meal-induced increase in rectal temperature. 6. It is concluded that changes in food intake observed during warming the scrotum were not a direct result of the sensory information signalling increased skin temperature. 7. The likely mechanisms involved are the interactions of peripheral and deep body temperature, decreased deep body temperature and increased heat loss.     

Preproghrelin-derived peptide, obestatin, fails to influence food intake in lean or obese rodents

Objectives: Obestatin has been initially characterized as a new peptide derived from the ghrelin precursor, which suppresses food intake and inhibits the orexigenic and prokinetic actions of ghrelin when injected peripherally or centrally in lean mice. However, reproducing these data remains controversial. Reasons for the disparity may be the use of different doses, routes, and animal models. We aimed to investigate the effects of peripheral and intracisternal (IC) injection of obestatin on feeding, gastric motility, and blood glucose in rats as well as in diet‐induced obese (DIO) mice. Research Methods and Procedures: Food intake and gastric emptying of a semi‐liquid caloric meal were measured after intraperitoneal (IP) injection of obestatin in rats and DIO mice. Gastric phasic motility and blood glucose were monitored in urethane‐anesthetized rats after IC or intravenous (IV) injection of obestatin. Results: Obestatin injected intraperitoneally at doses ranging from 0.1 to 3 mg/kg influenced neither acute food intake nor gastric emptying in rats. Obestatin injected intravenously at 0.3 or 3 mg/kg and IC at 7.5 or 30 µg/rat modified neither fasted gastric phasic motility nor blood glucose levels, while ghrelin (30 µg/kg, IV) increased and vagotomy suppressed gastric motility, and an oligosomatostatin analog (3 µg/rat, IC) decreased blood glucose. Obestatin, injected intraperitoneally (0.3 mg/kg) in DIO mice, did not alter feeding response to a fast, while urocortin 1 (10 µg/kg, IP) induced a 73.3% inhibition at 2 hours. Discussion: Our data demonstrate that peripheral administration of obestatin did not modify food intake in rats or obese mice or gastric motor function in rats.     

Effect of food restriction on energy intake and thermogenesis in Yunnan red-backed vole (Eothenomys miletus) with different metabolic levels

Shortage of food resources has significant effects on many physiological parameters of animals. The aim of the present study was to examine the relationship between the energetics countermeasures in response to food restriction and the levels of metabolism in Eothenomy miletus. Survival rate, body mass, basal metabolic rate (BMR), nonshivering thermogenesis (NST), body fat mass, serum leptin levels and other physiological parameters were measured. Animals were divided into high-BMR (hBMR) and low-BMR (lBMR) group. The two groups were restricted to 70% of ad libitum food intake for 4 weeks. The data showed that food intake increased by 24.5% in hBMR group than that in lBMR group before the experiment. Body mass, body fat mass, BMR and NST with hBMR or lBMR group significantly decreased after food restricting. Eighty percent of E. miletus survived with hBMR group, but 60% of E. miletus survived with lBMR group. Serum leptin levels were positively correlated with body mass, BMR and NST. The results suggested that E. miletus could apply physiological adjustments to adapt the period of food shortage by reducing energy metabolism, providing the support for the “metabolism switch hypothesis”. E. miletus with hBMR had decreased energy expenditure to maintain the normal physiological function. However, lBMR group could not decrease energy expenditure to meet the stress of available energy resource, which led to body mass decreased and mortality rate increased. Serum leptin levels may be involved in the regulation of energy balance and body mass in E. miletus during the food restriction.     

Effect of environment on the functional state of adolescents

Adolescents of both sexes 14–15 years of age residing under different environmental conditions have been examined. The group exposed to atmospheric pollution with sulfur-containing substances from a pulp-and-paper mill, as compared with the control (residing in a relatively “clean” area), is characterized by lower tolerance to hypoxemia, reserves of the cardiorespiratory system, core body temperature, level of physical health, concentrations of nitrogen oxide metabolites in the blood, and antioxidant vitamin supply. In addition, this group shows a tendency towards hypertension and worsening of hemodynamic regulation.     

Effect of cholecystokinin receptor antagonists on voluntary food intake in chickens

The effect of two cholecystokinin (CCK) receptor antagonists (L-364718 and L-365260) and of diazepam on voluntary food intake in chicken was studied. L-365260 significantly increased cumulative food intake at 30 and 60 min, whereas L-364718 had no effect. Diazepam also increased food intake at 30 minutes. It was therefore concluded that anxiolytic effects could account for an increase in food intake in the conditions under which the study was carried out. Consequently, the effect of L-365260 could either be due to its anxiolytic properties or to its direct effects on food intake control.     

Effect of novel NOP receptor ligands on food intake in rats

Nociceptin/orphanin FQ (N/OFQ), the endogenous ligand for the NOP opioid receptor, stimulates feeding in rats. The present study evaluated the effect of three newly synthesized NOP receptor agonists and two NOP receptor antagonist on food intake. Freely feeding rats were tested with intracerebroventricular (ICV) injections of the NOP receptor agonists OS-500, OS-462 and OS-461. OS-500 and OS-462 evoked a hyperphagic effect more potent and far more pronounced than that of N/OFQ, while OS-461 was ineffective. OS-500 and OS-462 were also tested by intraperitoneal injection, but were unable to evoke hyperphagia following this route of administration. The NOP receptor antagonist NC-797 and UFP-101 did not modify feeding in freely feeding rats while fully antagonized the hyperphagic effect of N/OFQ. Pre-treatment with UFP-101 but not with NC-797 antagonized the hyperphagic effect of OS-462 and OS-500. The present findings indicate that OS-500, OS-462 may act as potent and long-lasting NOP receptor agonists, whereas UFP-101 and NC-797 show antagonistic properties. The higher efficacy of UFP-101 in blocking the hyperphagic effect of OS-462 and OS-500 may be linked to the better pharmacokinetic profile of this antagonist compared to NC-797. Overall, the results indicate that these compounds may represent valuable pharmacological tools to investigate the role of the brain N/OFQ system.