Synergistic action of p-chloroamphetamine and fluoxetine on food and water consumption patterns in the rat.

The distribution of eating, drinking and body weight changes during the 24 hr day were examined following brain 5-HT depletion with p-chloroamphetamine (PCA). Following a baseline period, measurements of food and water intakes and body weights were recorded 1, 2, 3, 6, 12, 20 and 24 hr following PCA, 5.0 mg/kg, or saline. Other animals were pretreated with fluoxetine, 10.0 mg/kg, prior to either PCA or saline in an attempt to block the PCA effects. The results indicate acute hypophagia, hypodipsia, and body weight losses. These decreases were not influenced by the time of day when PCA was administered. Pretreatment with fluoxetine enhanced rather than blocked these effects. No long term changes in ingestive behavior were seen. These results are discussed with respect to the possible role of 5-HT in the control of ingestive behavior.     

Effects of body weight reduction and food deprivation on cocaine self-administration

The present experiments attempted to study the effects of food deprivation and body weight reduction on cocaine self-administration. Rats whose body weight was reduced to 80% free feeding weight (FFW) with 23 hours' food deprivation increased cocaine intake by 30-fold compared to 100% FFW animals. The results demonstrated that, in rats, body weight reduction and the state of food deprivation interact to further enhance self-administration of cocaine. From the practical point of view, the results suggest that there may be an increased risk of drug dependence with patients taking stimulants to control body weight.     

Effects of chronic phenylpropanolamine infusion and termination on body weight,food consumption and water consumption in rats

The present study determined the effect of chronic PPA infusion and withdrawal on weight regulation. Male Sprague-Dawley rats received PPA (0, 90 or 180 mg/kg) via miniosmotic pumps for 2 weeks. Body weight and food and water consumption were measured daily before, during, and for 2 weeks after PPA infusion. Additionally, body weight was measured once 6 weeks after the last day of drug administration. PPA infusion produced dose-dependent reductions in body weight and food consumption throughout drug administration. During the first week of PPA termination, food consumption returned to control levels; however, body weights of drug-treated animals remained below those of controls throughout the 6-week post-drug period. PPA depressed water intake during the first week of drug administration, but tolerance to this effect developed by the second week of administration. These results suggest chronic PPA infusion produces persistent appetite suppression and weight loss and that discontinuation of PPA does not result in hyperphagia or rapid weight gain. These findings may have clinical significance for the many individuals who wish to lose weight but have difficulty reducing intake without pharmacologic assistance.     

Effects of nicotine on body weight and food consumption in rats

Recent human and animal studies have found that cigarette smoking or nicotine administration is accompanied by decreased consumption of sweet-tasting, high caloric foods. Cessation of smoking or nicotine is accompanied by increased consumption of these foods. Changes in consumption of these specific foods may partially account for the inverse relationship between smoking or nicotine and body weight. The present research was designed to determine whether consumption of nonsweet food is affected by nicotine and whether continuous access to only nonsweet foods attenuates the body weight changes associated with nicotine administration and cessation of nicotine administration. Alzet miniosmotic pumps were implanted SC to administer saline or three different concentrations of nicotine to male Sprague-Dawley albino rats for 2–3 weeks. Two studies on a total of 80 rats found an inverse dose-response relationship between nicotine administration and body weight without changes in bland food or water consumption. After cessation of nicotine administration, there were no differences in food consumption or body weight changes between groups. The effects of nicotine on body weight, both during and after drug administration, were attenuated in comparison to the results of studies that provided sweet-tasting foods.     

Effects of nicotine on body weight and food consumption in female rats

Women often report that they smoke cigarettes to avoid weight gains and that they relapse after abstaining from tobacco because of weight gains. Men also report these concerns but to a lesser extent. This gender difference may reflect sociological and cultural pressures about physical appearance, or it may reflect sex differences in the effects of nicotine. The present research was designed to examine the effects of nicotine administration and cessation of nicotine on body weight, food consumption, and water consumption. Alzet miniosmotic pumps were implanted SC to administer saline or three different concentrations of nicotine to female Sprague-Dawley rats for 17 days. This paradigm has been used in previous studies of nicotine and body weight in male rats. Animals were used as subjects to avoid cultural factors and cognitive concerns about body weight. Nicotine administration decreased normal body weight gains and cessation of nicotine was accompanied by significant increases in body weight compared to controls. In contrast to previous studies of male rats, the nicotine-related changes in body weight were accompanied by changes in bland food and water consumption. These findings indicate that females are more sensitive than males to the effects of nicotine on body weight and feeding during and after drug administration.     

Effects of methylphenidate on schedule dependent and schedule induced behavior.

The effects of methylphenidate, 1.5, 3.0, 6.0 and 12.0 mg/kg, on lever pressing, schedule induced licking, and drinking were studied. The generator schedule was a fixed interval 1 min food reinforcement schedule. The effects were assessed when animals were reduced to 80% body weight by partial food deprivation and when allowed to recover body weight under conditions of ad lib eating. Results indicate that under body weight conditions methylphenidate significantly decreases schedule induced licking and drinking but does not affect lever pressing.     

Effects of intracranial injections of 6-OHDA on food and water intakes,body temperature and body weight regulation in the rat

6-Hydroxydopamine was injected either intraventricularly (320 μm in 10 μl) or intrahypothalamically (64 μg in 2 μl) into rats kept under either free feeding or body weight reduced conditions. Intraventricular injections caused a temporary aphagia and hypodipsia in free feeding rats but daily measurements failed to reveal any long term effects; body weight reduced rats did not display the temporary aphagia but were initially hyperphagic. Injections into the more rostral hypothalamic areas of free feeding rats also showed only minimal short term effects; however, some of the body weight reduced group died within several days of injection. Injections made at more posterior loci again showed very little effect in both body weight reduced and free feeding groups; some temporary disruption of feeding occured from lesions in the proximity of the zona incerta of some free feeding animals.     

Naloxone: Effects on food and water consumption in the non-deprived and deprived rat

Naloxone (0.5–5 mg/kg) reduced both food and water intake in non-deprived male rats, tested in the dark phase of the light-dark cycles in their home cages. These effects were transient; food and water-intake were restored to control levels by the end of the 8-h test period. The effects were also not dose-related. Naloxone (1 and 5 mg/kg) also reduced water-intake in water-deprived and food-deprived animals, without altering food-intake. These results suggested that naloxone may exert a primary antidipsogenic action, that does not depend upon any suppression of feeding. A final experiment showed that naloxone can completely abolish the thirst produced by injection of a hypertonic saline solution. This experiment also demonstrated that naloxone could suppress feeding, even though food intake was markedly inhibited by the osmotic thirst stimulus. Hence, the activation of feeding responses (e.g. by food deprivation) is not a necessary condition for naloxone to suppress feeding. The implications of these results for the control of feeding and drinking responses are briefly considered.     

Influence of tetrahydrocannabinols (delta8-THC and delta9-THC) on body weight, food, and water intake in rats

Female Wistar rats, six to a group, were injected daily for a 23-day period with Δ⁸-THC (5.0 mg/kg), Δ⁹-THC (2.5 mg/kg) or vehicle. Body weight, food and water intake were recorded every second day. It was found that Δ⁸-THC caused a decrease of body weight, to a level maintained throughout the injection period, with only slight signs of recovery. Both drugs caused a marked decrease of water intake. Food intake was not significantly affected by the drugs. Factors in relation to the effects of THC on body weight, food and water intake are discussed.     

Blood glucose and body temperature alterations induced by ethanol in rats submitted to different levels of food deprivation

The effects of 1.0, 3.0 and 5.0 g/kg of ethanol on blood glucose levels and body temperature were examined in rats submitted to either acute food deprivation (24 or 48 hr), chronic starvation, or to both chronic plus acute food deprivation. The results show that: (a) 3.0 and 5.0 g/kg produced either an increase or a decrease of glucose levels depending on the state of fasting; (b) rats not deprived of food presented hyperglycemia while being hypothermic; (c) a marked hypothermia was present when no substantial alterations in glycemia were observed; and (d) in cases where hypoglycemia and hypothermia occurred, the fall in body temperature paralleled or preceded the decrease in glucose levels.     

Effects of food deprivation on etonitazene consumption in rats.

One group of free-feeding rats was given a 5 microgram/ml etonitazene HCl solution as their sole liquid. This group increased their drug intake by 100% when they were partially food-deprived during a 23-day period. Another group that remained food-satiated and received etonitazene for an equal number of days did not show similar increases in drug intake. However, this group drank greater volumes of the etonitazene solution than a food-satiated control group drank of water. These results are contrasted with a fourth group showing a 50% decrement in water intake during similar food-deprived conditions. The food-deprived group drinking etonitazene showed highly erratic drinking patterns compared to all the other groups. Daily liquid intake ranged from 30 to 250 ml in this group, and volumes oscillated from high to low on alternating days. When the food-deprived/food-satiated conditions were replicated in this experimental group, corresponding increases and decreases in drinking reliably occurred. However, during the second food-deprived phase, the large increases occurred almost immediately as contrasted with a gradual increase over 17 days during the first food-deprived phase. This would suggest a learning mechanism may be involved. Self-mutilation and other forms of stereotypy were noted only in food-deprived rats consuming etonitazene.     

Effects of chronic haloperidol treatment on ingestive behaviour and body weight regulation in the rat

This study was designed to investigate the effects of two doses of haloperidol on body weight, food spillage and food and water intake using rats as subjects. In the first experiment, 12 male Wistar albino rats were observed in individual cages for 30 days, six receiving a daily injection of haloperidol (1 mg/kg IP in 1 ml/kg isotonic saline), while the other six received a control injection of isotonic saline in the experimental phase. In the second experiment, 12 rats were observed for 9 days in individual cages, six receiving a daily injection of 10 mg/kg haloperidol in 4 ml/kg isotonic saline in the experimental phase. In both studies, haloperidol depressed food intake and food spillage. With the lower dose of haloperidol (1 mg/kg), body weight was not depressed until several days after a significant reduction of food intake had been recorded. With the higher dose (10 mg/kg), body weight was depressed during the first 24 h, but quickly returned to normal, although food intake remained depressed. It is suggested that haloperidol may have a limited facilitatory effect on body weight.     

The importance of sweet taste and caloric content in the effects of nicotine on specific food consumption

There is an inverse relationship between nicotine and body weight that has been partially explained by changes in consumption of sweet-tasting high calorie foods. The present research was designed to determine the relative importance of sweet taste and caloric content in the effects of nicotine on specific food consumption and body weight. Alzet miniosmotic pumps were implanted SC to administer saline or two different concentrations of nicotine to 63 male Sprague-Dawley rats for 17 days. Three experiments were performed in which animals had access to two foods, a nonsweet low calorie food and a target food (sweet low calorie, sweet high calorie, or nonsweet high calorie). Body weight, food consumption, and water consumption were measured daily before, during, and after drug administration. In all three experiments, there was an inverse relationship between nicotine and body weight. Both sweet taste and caloric content were involved in the effects of nicotine on specific food consumption and body weight, but sweet taste was particularly important. In fact, the effects of nicotine on body weight were attenuated when sweet-tasting low calorie foods were available. These findings have implications for controlling body weight gains after cessation of cigarette smoking.     

Effects of caffeine on FT-1 min schedule induced drinking at different body weights

The effects of caffeine (3.125, 6.25, 12.5, 25.0, 50.0, and 100.0 mg/kg) on lever pressing, schedule induced licking, and water consumption induced by a fixed time 1 min schedule of food reinforcement were studied. Changes in these dependent variables were assessed when animals were reduced to 80% of their initial body weight by partial food deprivation and when body weight recovered after the animals were returned to conditions of ad lib feeding. Results indicate similar decreases in licking and drinking at the highest doses of caffeine under both feeding and body weight conditions. The results were compared to previous research which evaluated the effects of caffeine on adjunctive behavior.     

Differential effects of morphine on food and water intake in food deprived and freely-feeding rats

In two experiments the effects of a range of doses of morphine (1, 3, 10 and 30 mg/kg) on the food and water consumption of rats were studied. The results of the first experiment showed that in 24 h food-deprived rats, morphine reduced levels of food and water intake. The duration of these actions was dependent upon dose, with only the highest dose (30 mg/kg) producing any effect persisting for longer than 4 h. In contrast a second experiment showed that morphine increased levels of food and water intake in non-deprived animals. The effect on food intake was most apparent when measurements were taken at 2 h and 4 h after drug administration, while water intake remained above control levels for over 6 h. This study shows that the actions of morphine on ingestion of food and water are affected by food deprivation, and the results are consistent with the hypothesised role of endogenous opiates in the mediation of such behaviour.     

Behavioral effects of pergolide mesylate on food intake and body weight

In a crossover design experiment, pergolide mesylate significantly suppressed food intake and body weight in spayed female rats. Inhibition of food intake by a constant dose of pergolide progressively diminished with repeated administrations. Pergolide continued to suppress body weight with no indications of tolerance. When pergolide was discontinued, body weight increased sufficiently to compensate for the loss and failure to gain during drug treatment. A second experiment investigated the observation that animals injected first with vehicle showed greater anorexia when subsequently injected with pergolide than did animals injected first with pergolide. In addition, tolerance was further assessed by administering on two occasions a higher dose of pergolide. Following chronic pergolide treatment, this dose was insufficient to reinstate anorexia; however, after a period of abstinence, this dose produced anorexia comparable to that observed at the beginning of pergolide treatment. Due to pergolide mesylate's action as a postsynaptic dopamine agonist, a dopaminergic neural system is implicated in pergolide induced anorexia.     

The effects of intrahypothalamic injections of desmethylimipramine on food and water intake of the rat

The effects on eating and drinking of injections of desmethylimipramine (DMI) into the lateral hypothalamus of the rat were examined under four conditions of food- and water-deprivation (food- and water-satiated; 16 hr food-deprived and water-satiated; food-satiated and 11 hr water-deprived; 16 hr food-deprived and 11 hr water-deprived). DMI increased eating in animals that were food-deprived and water-satiated; and increased drinking in animals that were food- and water-satiated. No other effects on eating and drinking were observed. The results are discussed in terms of current hypotheses concerning the adrenergic and cholinergic actions of DMI and other tricyclic antidepressants.     

Chronic administration of nalmefene leads to increased food intake and body weight gain in mice

Nalmefene is an orally available opioid receptor antagonist that has been shown to suppress appetite in humans, but its effects on chronic food intake and body weight remain unclear. Here, we report that chronic (21-day) oral administration of nalmefene at 2 or 10 mg/kg/day in diet-induced obese (DIO) mice led to significant increases (9-11%) in cumulative food intake. Mice in the nalmefene-treated groups also gained body weight at a rate faster than the control. Body composition analysis showed that the extra body weight gains in the treated animals were mostly due to increased fat accumulation. Since acute nalmefene treatment showed a trend toward a decrease rather than an increase in food intake, it is possible that the orexigenic effect of chronic oral administration of nalmefene was caused by pharmacologically active metabolites rather than the drug itself. Our results argue against the potential use of nalmefene for treating human obesity.     

分娩方式与不同体重新生儿凝血四项的研究

目的 探讨新生儿凝血四项功能与分娩方式、体重的关系,分析新生儿凝血生理及其影响因素,为临床提供参考依据.方法 取644例不同分娩方式和体重的新生儿的血浆进行凝血四项即凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、纤维蛋白原(FIB)和凝血酶时间(TT)的测定.结果 与对照组相比,顺产组和剖宫产组的第1组凝血四项均明显增加(P＜0.01),第2组PT、APTT延长(P＜0.05)但FIB、TT值无显著差异(P＞0.05),第4组凝血四项均无显著差异(P＞0.05).剖宫产组的第1组与顺产组的第1组相比,PT、APTT延长(P＜0.05),TT、FIB值无显著差异(P＞0.05);其余相对应组的凝血四项无显著差异(P＞0.05).结论 新生儿凝血四项受体重影响,体重越轻凝血时间越长,并随着体重的增加逐渐缩短,纤维蛋白原则逐渐增多;分娩方式主要对体重＜1500g的新生儿的凝血功能有影响.     

Differential effects of chronic naltrexone treatment on food intake patterns and body weight in rats depend on their food deprivation status

The aim of the present study was to assess the effect of chronic naltrexone treatment on daily patterns of food intake in food-deprived and free-feeding rats. In experiment 1, Wistar male rats had continuous access to food and water, while in experiment 2 they were deprived of food for 12 h/day. Animals in both experiments were studied as follows: a baseline period (7 days), followed by a treatment period (14 days) with either saline or naltrexone at 10 mg/kg/day. Finally, a post-treatment period (7 days) was assessed. Food and water consumption were measured every 2 h after the naltrexone or saline injection for 12 h and once more 12 h later. Experiment 1: Food intake was higher in the naltrexone group 10 h after injection. Total food intake and body weight gain were higher in the naltrexone group than in the saline group in the second week of treatment and in the post-treatment period. Experiment 2: The overeating observed in the saline group in the hours following the 12 h of the food deprivation period was suppressed by naltrexone, though total daily food intake was not affected. Body weight gain was initially reduced by naltrexone, but a rebound effect was observed during the post-treatment period in the naltrexone group. Naltrexone produced a differential effect on food intake and body weight that depended on the rats' food deprivation status. These results could be explained in terms of opioid receptor up-regulation that enhances the rewarding effects of food or by naltrexone-produced changes in palatability.