Effect of an oral supplementation with a proprietary melon juice concentrate (Extramel) on stress and fatigue in healthy people: a pilot, double-blind, placebo-controlled clinical trial

BACKGROUND

Recent studies have demonstrated a correlation between perceived stress and oxidative stress. As SOD is the main enzyme of the enzymatic antioxidant defence system of the body, we evaluated the effect of an oral daily intake of a proprietary melon juice concentrate rich in SOD (EXTRAMEL) on the signs and symptoms of stress and fatigue in healthy volunteers.

METHODS

This randomized, double blind, placebo controlled clinical study was conducted with seventy healthy volunteers aged between 30 and 55 years, who feel daily stress and fatigue. They took the dietary supplement based on the melon juice concentrate (10 mg Extramel corresponding to 140 IU SOD per capsule) or a placebo one time daily during 4 weeks. Stress and fatigue were measured using four observational psychometric scales: FARD, PSS-14, SF-12 and Epworth scale. The study was conducted by Isoclin, a clinical research organization, located in Poitiers, France.

RESULTS

No adverse effect was noted. The supplementation with the proprietary melon juice concentrate bringing 140 IU SOD/day significantly improved signs and symptoms of stress and fatigue linked to performance, physical (pain, sleep troubles), cognitive (concentration, weariness, sleep troubles) or behavioural (attitude, irritability, difficulty of contact) compared to the placebo. In the same way, quality of life and perceived stress were significantly improved with SOD supplementation.

CONCLUSION

This pilot study showed that an oral supplementation with a proprietary melon juice concentrate rich in SOD may have a positive effect on several signs and symptoms of perceived stress and fatigue.

Neurobehavioral maturation of offspring from epileptic dams: study in the rat lithium-pilocarpine model

In the present study, we explored the consequences of epilepsy on the neurobehavioral development of the offspring in a rat model of spontaneous epilepsy, the lithium-pilocarpine model of temporal lobe epilepsy not dependent on genetic factors and in animals not receiving any antiepileptic treatment. Status epilepticus was induced by lithium-pilocarpine in female rats. After the occurrence of spontaneous seizures the rats were mated and the neurobehavioral development of the offspring was explored. Rat pups were cross-fostered early after birth. We hence obtained pups born from or raised by epileptic or non-epileptic dams. On the dams, we performed a follow-up of maternal care during pregnancy. On the pups, we performed a follow-up of classical parameters of development such as body weight and eyelid opening, and subjected the pups to various tests representative of neurobehavioral maturation extending from postnatal day 4 (PD4) to PD30 (righting reflex, suspension time, negative geotaxis, open field, locomotor coordination and eight arm maze). Altogether our data show that rat pups born from or raised by epileptic dams develop as well as control pups raised by control dams. Intriguingly, pups born from lithium-pilocarpine exposed dams and raised by control mothers tend to have better scores than the two other groups in all tests. This indicates that the exposure to seizures during pregnancy is not harmful for the development of the fetus.

Variations in illumination, closed wall transparency and/or extramaze space influence both baseline anxiety and response to diazepam in the rat elevated plus-maze

Numerous methodological-related variables have been demonstrated to influence the baseline anxiety level of rodents exposed to the elevated plus-maze (EPM), raising questions about the sensitivity of this test for the detection of the effects of anxiolytic drugs. Thus, the present study was designed (1) to assess the combined effects of illumination (40-lx red or white light), closed wall type (walls made of translucent or opaque material) and extramaze space size (small or spacious experimental room) on rat behaviour, and (2) to investigate the effects of such parameters on the relevance of the maze for detecting the effects of diazepam orally administrated at the anxiolytic dose of 3 mg/kg. Results indicate that illumination and closed wall type are two main independent parameters that are able to modify the open arm avoidance. Moreover, the closed wall type interacts with the extramaze space size since the reduction of the open arm exploration induced by opaque closed walls is two-fold stronger in the spacious experimental room than in the small one. Finally, the diazepam anxiolytic activity is significantly detected in our laboratory in specific EPM conditions (maze with opaque walls, use of a red light, maze located in a spacious experimental room). In conclusion, the present study demonstrates that an inappropriate baseline anxiety level due to the methodological use of the EPM can dramatically reduce the sensitivity of the maze for the detection of benzodiazepine-related compounds. This study also provides new insights into the perception of the EPM open space in rats.

Efficacy of αs1-casein hydrolysate on stress-related symptoms in women

OBJECTIVE

To examine the effects of alpha (s1)-casein hydrolysate on females with stress-related symptoms.

DESIGN

Double-blind, randomized, crossover, placebo-controlled trial.

SETTING

The alpha (s1)-casein hydrolysate was manufactured by INGREDIA (Arras, France) and the placebo was manufactured by DIETAROMA (Bourg, France). Study was designed and performed at PROCLAIM (Rennes, France), and the statistical analyses were performed by D Desor (Nancy, France).

SUBJECTS

A total of 63 female volunteers suffering from at least one disorder that may be related to stress such as anxiety, sleep problems and general fatigue.

INTERVENTIONS

A total of 63 volunteers participated in a double-blind, randomized, crossover, placebo-controlled study. Subjects were randomly allocated to receive either tablets containing alpha (s1)-casein hydrolysate or placebo at the dose of 150 mg/day for 30 days. After a 3 weeks washout period, they were crossed over for a new 30-day period of tablets intake. The outcome measure was a questionnaire including 44 items of symptoms that may be related stress in which the severity of each sign was evaluated using a 10-degree scale. These measures were studied repeatedly at the day of 0, 15 and 30 after the start of each interventional period.

RESULTS

The 30-day treatment by alpha (s1)-casein hydrolysate in females with stress-related symptoms reduced their symptoms, particularly in digestion (P<0.01), cardiovascular (P<0.05), intellectual (P<0.01), emotional (P<0.05) and social problems (P<0.05).

CONCLUSION

This study showed that a 30-day ingestion of alpha (s1)-casein hydrolysate decreased the stress-related symptoms in females suggesting that this product may be used as an effective functional ingredient alleviating such symptoms.

SPONSORSHIP

This study was partially supported by the INGREDIA of France and Neurobiology Research Program from the Korea Ministry of Science and Technology (2004-01757) of Korea.

Ethological comparison of the effects of a bovine αs1-casein tryptic hydrolysate and diazepam on the behaviour of rats in two models of anxiety

A bovine alpha s1-casein tryptic hydrolysate was previously demonstrated to display an anxiolytic-like activity in the conditioned defensive burying and in the elevated plus-maze models when i.p. injected. The present study assessed the anxiolytic-like effects of this tryptic hydrolysate after an oral administration in rats faced to the same behavioural situations using diazepam as a reference. In a first experiment, the behavioural effects of the hydrolysate in the conditioned defensive burying test were investigated at doses ranging 5-50 mg/kg. The results showed that the minimal dose required to elicit an anxiolytic-like activity is 15 mg/kg. In a second experiment, the alpha s1-casein tryptic hydrolysate (15 mg/kg, p.o.) was demonstrated to display an anxiolytic-like activity similar to diazepam (3 mg/kg, p.o.) in the conditioned defensive burying test and the elevated plus-maze. However, the ethological analysis of behaviour indicated that this hydrolysate has a different activity compared to diazepam. While diazepam induced a disinhibition state in rats, possibly related to the risk-taking behaviour observed after a benzodiazepine ingestion in humans, the tryptic hydrolysate did not display such a side effect. These results suggest that the mechanism of action of the bovine alpha s1-casein tryptic hydrolysate may differ from that of diazepam.

Behavioural and cognitive effects of oligofructose-enriched inulin in rats

The behavioural and cognitive effects of oligofructose-enriched inulin at the doses of 5 and 10 % in the diet, orally ingested daily during 2 weeks, were investigated using a functional observational battery (FOB) and the light extinction test in male Wistar rats. Control rats received a standard diet and were tested in the same test situations. The behavioural effects were assessed 2 d before and 14 d after the beginning of the treatment period and the cognitive effects were investigated after the administration period by lever-pressing activity and learning discrimination using the light extinction test paradigm. In general, the study demonstrated that oligofructose-enriched inulin at 5 % in the diet, and particularly at 10 % in the diet, caused relaxing-like effects, stimulated and increased the general activity and interest of the rats to the test environment. In addition, both doses of oligofructose-enriched inulin showed significant effects on learning discrimination in male rats, in comparison with the control diet. These results suggest that oligofructose-enriched inulin, particularly at the dose of 10 %, improves cognitive performances in the light extinction test and the well-being of male rats using the FOB.

A 5-month period of epilepsy impairs spatial memory, decreases anxiety, but spares object recognition in the lithium-pilocarpine model in adult rats

PURPOSE

In temporal lobe epilepsy (TLE), interictal behavioral disorders affect patients' quality of life. Therefore we studied long-term behavioral impairments in the lithium-pilocarpine (li-pilo) model of TLE.

METHODS

Eleven li-pilo adult rats exhibiting spontaneous recurrent seizures (SRSs) during 5 months were compared with 11 li-saline rats. Spatial working memory was tested in a radial arm maze (RAM), anxiety in an elevated plus-maze (EPM), and nonspatial working memory in an object-recognition paradigm. Neuronal loss was assessed on thionine brain sections after behavioral testing.

RESULTS

In the RAM, the time to complete each session and the number of errors per session decreased over a 5-day period in li-saline rats but remained constant and significantly higher in li-pilo rats. In the EPM, the number of entries in and time spent on open arms were significantly higher in li-pilo than li-saline rats. In the object-recognition task, the two groups exhibited a comparable novelty preference for the new object. Neuronal loss reached 47-90% in hilus, CA1, amygdala, and piriform and entorhinal cortex.

CONCLUSIONS

In li-pilo rats having experienced SRS for 5 months, performance in the object-recognition task is spared, which suggests that object discrimination remains relatively intact despite extensive damage. Neuronal loss in regions mediating memory and anxiety, such as hippocampus, entorhinal cortex, and amygdala, may relate to impaired spatial orientation and decreased anxiety.

Phospholipid transfer protein (PLTP) deficiency reduces brain vitamin E content and increases anxiety in mice

Vitamin E supplementation constitutes a promising strategy in the prevention of neurodegenerative diseases. Here, we show that a phospholipid transfer protein (PLTP) is widely expressed in the brain where it appears to function as a transfer factor for alpha-tocopherol, the main isomer of vitamin E. PLTP deficiency results in significant depletion of brain alpha-tocopherol in both homozygous (-30.1%, P<0.0002) and heterozygous (-18.0%, P<0.05) PLTP knocked-out mice. Alpha-tocopherol depletion in PLTP-deficient homozygotes is associated with the elevation of lipofuscin (+25% and +450% increases in cortex and substantia nigra, respectively), cholesterol oxides (+54.5%, P<0.05), and cellular peroxides (+32.3%, P<0.01) in the brain. Complete PLTP deficiency in homozygotes is accompanied by increased anxiety as shown by fewer entries (8.3% vs. 44.4% in controls, P<0.01) and less time spent (1.7% vs. 41.3% in controls, P<0.05) in the open arms of an elevated plus-maze, in the absence of locomotor deterioration. Thus, the vitamin E transfer activity of PLTP appears to be a key process in preventing oxidative damage in the brain, and PLTP-deficient mice could be a new model of the contribution of oxidative brain injury in the etiology of neurodegenerative diseases.

The endogenous androgen-regulated sialorphin modulates male rat sexual behavior

In sexually mature male rats, sialorphin is synthesized under androgenic control and its surge endocrine secretion is evoked in response to environmental acute stress. These findings led us to suggest that this signaling mediator might play a role in physiological and behavioral integration, especially reproduction. The present study investigates the effects induced by sialorphin on the male sexual behavior pattern. Intact male rats were treated in acute mode, with sialorphin at the 0.3, 1, and 3 microg/kg doses, before being paired with receptive female for 45 min. The data obtained show that sialorphin increased, in a dose-related manner, the occurrence of intromissions across the successive ejaculatory sequences. The rats treated with the highest 3 microg/kg dose significantly ejaculated less often compared to controls; however, 80% of them achieved up to three ejaculations. Further analyses of mount bouts for rats achieving three ejaculations reveal that there were significant stimulatory effects of sialorphin, at all doses, on the frequency of intromissions before ejaculation and on the propensity of males to engage in investigatory behavior directed to the female during the post-ejaculatory interval. Thus, sialorphin has the ability to modulate, at doses related to physiological circulating levels, the male rat mating pattern, that is, exerting a dual facilitative or inhibitory dose-dependent effect on the sexual performance, while stimulating the apparent sexual arousal or motivation. These findings led us to speculate that the endogenous androgen-regulated sialorphin helps modulate the adaptative balance between excitatory and inhibitory mechanisms serving appropriate male rat sexual response, depending on the context.

Effects of a tryptic hydrolysate from bovine milk αS1–casein on hemodynamic responses in healthy human volunteers facing successive mental and physical stress situations

BACKGROUND

Preclinical results in rats have demonstrated anxiolytic-like effects of a tryptic bovine alphaS1-casein hydrolysate.

AIM OF THE STUDY

We investigated the putative effects of this tryptic hydrolysate on systolic (SBP), diastolic (DBP) blood pressures, heart rate (HR) values and plasma cortisol concentrations (CC) in human healthy volunteers facing successive stress situations.

METHODS

The subjects were (double blind) randomly allocated to ingest three times, 12 hours apart, two capsules containing either 200 mg of alphaS1-casein hydrolysate (TS) or bovine skimmed milk powder as a placebo (CS). On the morning of the test day, a first blood sample for baseline measurement of CC was taken before the subjects were submitted to the Stroop test (ST) and, after a 30-min rest, to a Cold Pressor test (CPT). SBP, DBP, and HR were continuously recorded for 5 min before the ST and during each stress situation. A second blood sample was taken 15 min after the end of the CPT condition.

RESULTS

ST and ST + CPT combined test situations increased SBP, DBP and HR. The significant "Treatment x SBP" and "Treatment x DBP" interactions indicated the lower percentage changes in SBP and DBP of the TS. In addition, the results showed a significant decrease of the CC in the TS but not in the CS throughout the ST + CPT combined stress tests. HR remained stable in TS between the initial rest period and the CPT unlike what happened in CS.

CONCLUSION

On the basis of blood pressure and cortisol changes, these results suggest an antistress profile of this alphaS1-casein hydrolysate in human subjects.

Histopathological alterations and functional brain deficits after transient hypoxia in the newborn rat pup: a long term follow-up

To assess temporal brain deficits consecutive to severe birth hypoxia, newborn rats were exposed for 20 min to 100% N2. This treatment induced a long-term growth retardation and a delayed, but only transient, neuronal loss (approximately 25%) in the CA1 hippocampus and parietal cortex, starting from 3 days and peaking at 6 days post-hypoxia. The expression profiles of various apoptosis-regulating proteins (including Bcl-2, Bax, p53 and caspase-3) were well correlated to the alterations of nuclear morphology depicted by 4,6-diamidino-2-phenylindole (DAPI). Whereas they confirmed a gradual histological recovery, specific DNA fragmentation patterns suggested that birth hypoxia may transiently reactivate the developmental programme of neuronal elimination. Although they successfully achieved various behavioral tests such as the righting reflex, negative geotaxis, locomotor coordination, and the eight-arm maze tasks, both developing and adult hypoxic rats were repeatedly slower than controls, suggesting that birth hypoxia is associated to moderate but persistent impairments of functional capacities.

Sialorphin, a natural inhibitor of rat membrane-bound neutral endopeptidase that displays analgesic activity

Sialorphin is an exocrine and endocrine signaling mediator, which has been identified by a genomic approach. It is synthesized predominantly in the submandibular gland and prostate of adult rats in response to androgen steroids and is released locally and systemically in response to stress. We now demonstrate that the cell surface molecule to which sialorphin binds in vivo in the rat kidney is the membrane-anchored neutral endopeptidase (neprilysin; NEP, EC 3.4.24.11). NEP plays an important role in nervous and peripheral tissues, as it turns off several peptide-signaling events at the cell surface. We show that sialorphin prevents spinal and renal NEP from breaking down its two physiologically relevant substrates, substance P and Met-enkephalin in vitro. Sialorphin inhibited the breakdown of substance P with an IC50 of 0.4-1 microM and behaved as a competitive inhibitor. In vivo, i.v. sialorphin elicited potent antinociceptive responses in two behavioral rat models of injury-induced acute and tonic pain, the pin-pain test and formalin test. The analgesia induced by 100-200 mcicrog/kg doses of sialorphin required the activation of mu- and delta-opioid receptors, consistent with the involvement of endogenous opioid receptors in enkephalinergic transmission. We conclude that sialorphin protects endogenous enkephalins released after nociceptive stimuli by inhibiting NEP in vivo. Sialorphin is a natural systemically active regulator of NEP activity. Furthermore, our study provides evidence that it is a physiological modulator of pain perception after injury and might be the progenitor of a new class of therapeutic molecules.

The delivery rate of dietary carbohydrates affects cognitive performance in both rats and humans

RATIONALE

Glucose is the main metabolic fuel of the brain. The rate of glucose delivery from food to the bloodstream depends on the nature of carbohydrates in the diet, which can be summarized as the glycaemic index (GI).

OBJECTIVES

To assess the benefit of a low versus high GI breakfast on cognitive performances within the following 4 h.

METHODS

The influence of the GI of the breakfast on verbal memory of young adults was measured throughout the morning in parallel to the assessment of blood glucose levels. The learning abilities of rats performing an operant-conditioning test 3 h after a breakfast-like meal of various GI was also examined.

RESULTS

A low GI rather than high GI diet improved memory in humans, especially in the late morning (150 and 210 min after breakfast). Similarly, rats displayed better learning performance 180 min after they were fed with a low rather than high GI diet.

CONCLUSION

Although performances appeared to be only remotely related to blood glucose, our data provide evidence that a low GI breakfast allows better cognitive performances later in the morning.

Influence of environment structure and food availability on the foraging behaviour of the laboratory rat

According to the optimal foraging theory, an animal is expected to enter into a given activity depending on associated costs and benefits. In line with this assumption, numerous studies have suggested that energetic reward is balanced by predation risk in foraging decisions. Therefore, the use of information about indirect cues of predation risk such as physical structure (e.g. cover, escape substrate) can give individuals a selective advantage. We studied foraging behaviour in the laboratory rat in an experimental maze; it allowed us to vary two environmental parameters: food availability and physical structure. In a first experiment, rats were offered a choice between two areas only differing in cover density. In a second experiment, the two areas only differed in food density. In a third experiment, we crossed both parameters. Our results showed that high "cover" patch was preferentially exploited (experiment 1) and that rats foraged more in the high food density patch (experiment 2). The last experiment showed that rats partially trade-off between cover density and food availability, even if the safest area was still preferred. Therefore, we suggest that foraging decisions depend primarily on safety needs, rather than food availability, at least when animals are not severely food-deprived.

Behavioural differentiation of rats confronted to a complex diving-for-food situation

Previous studies have shown that a behavioural differentiation appeared in groups of rats subjected to an experimental design in which access to the feeder was made difficult. Some rats brought back food pellets to the cage (divers) while the others (non-divers) stayed in the sole home cage and obtained food only by stealing it from divers. In this study, we elaborated a more complex diving-for-food device which allowed divers to consume the food in a second cage away from non-divers. As a result, the expected lack of suppliers should not allow the emergence of the non-diver status. Unexpectedly, our results showed the apparition of non-divers and the persistence of divers (divers c1) bringing food back to the initial cage. Two new categories of rats appear: individuals which consume the food in the second cage where they stay once they have reached it (divers c2), or occasionally go back to the initial cage throughout the experiment (divers c1c2). Our results show the influence of spatial environment on social organization of rats and suggest that social pressure strongly determines the emergence of specialized roles in a group.

Behavioral evaluation of visceral pain in a rat model of colonic inflammation

A new rat model was established up to evaluate the antinociceptive effect of compounds in visceral pain. The test consisted in measuring the performance of rats in an aversive light stimulus avoidance experimental device. Rats with TNBS-induced colitis had a lower number of total active lever pressings and did not discriminate the active lever from the inactive one. Morphine (1 mg/kg, s.c.) and CI-977 (0.001 mg/kg, s.c.) treatment restored the level of pressing activity of animals and their ability to discriminate the active lever from the inactive one. Naloxone treatment antagonized the improvement of performance produced by morphine. The results obtained indicate that this behavioral paradigm may be used to evaluate the antinociceptive potential of compounds.

[Effect of fluoxetine treatment on serotonin and MHPG in 32 patients with major depressive disorder]

Considering the concept that depressive disorders were not only resulting from activity of one neurotransmitter, possible interactions between the noradrenergic system and a selective serotonin uptake inhibitor, fluoxetine, were investigated in order to test the hypothesis of noradrenergic or serotonergic involvement in depression. So the biological parameters (plasma and urinary MHPG, platelet serotonin) were evaluated by HPLC. The aim of this study was to evaluate the correlations between the concentrations of MHPG and serotonin in 32 melancholic patients treated by fluoxetine (20 mg/day) during a minimum of three weeks. The clinical examination with evaluation of the antidepressant effect carried out using the HDS/MES rating scale, allowed to divide the patients into three groups: responders to treatment, partial responders and non responders. In the same time, a control group of healthy subjects was investigated. ANOVA applied to platelet serotonin at day 0 showed a tendency toward heterogeneity between the three patient groups and the control group. The concentrations of serotonin in the three patients groups were highly reduced after 21 days of treatment. Concerning plasma and urinary MHPG there was non significant difference among the three patients groups at day 0 and the control groups. After treatment by fluoxetine, the results suggest that the urinary sulfate MHPG is an indicator of the metabolism of brain norepinephrine and seems to be a better turnover indicator than the plasma sulfate MHPG. The selective evaluation of sulfate and glucuronide MHPG could give a better survey of the psychobiological state of the patients than the total MHPG evaluation.

Effects of fluoxetine and norfluoxetine on 5-hydroxytryptamine metabolism in blood platelets and brain after administration to rats

The effects of intraperitoneal administration of fluoxetine (2.5, 5, 10 or 20 mg kg(-1)) and norfluoxetine (10 mg kg(-1)) on 5-hydroxytryptamine (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) metabolism were examined in the blood platelets and brain of rats killed 3 h after a single dose. Several experiments were performed to evaluate the effect of norfluoxetine. Plasma 5-HT concentrations decreased significantly (48%) compared with control group results 3 h after administration of a single dose of fluoxetine (10 or 20 mg kg(-1)). Similar plasma 5-HT levels, 0.54+/-0.04 and 0.56+/-0.09 mg L(-1), respectively, were observed after administration of 10 mg kg(-1) fluoxetine or norfluoxetine. In the same way 5-HIAA levels in whole brain were similar, 0.36+/-0.03 and 0.34+/-0.01 microg(-1), respectively, after administration of fluoxetine or norfluoxetine. There was a good correlation between plasma and brain levels of fluoxetine (0.962) and norfluoxetine (0.957). The results suggest that fluoxetine and norfluoxetine lead to reduced levels of 5-HT in platelets and of 5-HIAA in the brain. Like the parent drug, norfluoxetine is a potent and selective inhibitor of 5-HT uptake.

Effect of aluminum on superoxide dismutase activity in the adult rat brain

Male rats were treated daily with an intraperitoneal injection of 15 mg aluminum (Al chloride)/kg body weight for 17 d, in order to study the effects on superoxide dismutase (SOD) activities in the brain (cortex). No significant difference between control and treated animals was registered in the Cu/Zn and Mn SOD activities in the gray matter of the cortex. High Al levels were found in the plasma, the spleen, and the liver of the treated animals in comparison to the controls, but not in the cortex homogenates (gray matter). In addition, Al induced a significant decrease in food ingestion and weight gain.

Long-term effects of early diazepam exposure on social differentiation in adult male rats subjected to the diving-for-food situation

The present study was designed to investigate the consequences of a chronic diazepam (DZ) exposure (10 mg/kg/day) during the first 3 weeks of life on social behavior of adult male rats measured in a situation of restricted access to food, the diving-for-food model. The treatment had no long-term effects on the acquisition of social roles related to feeding. However, DZ-exposed rats were less efficient than controls in carrying food from the feeder to the cage during the 1st session but were able to adapt and improve their performances during the 2nd one. In the home cage, DZ-exposed rats were more aggressive toward conspecifics than controls and compensated for their deficit of food by stealing it from the others. These results suggest that an early DZ exposure has long-term consequences on social behavior of rats, possibly reflecting a reduction of the level of emotionality.

[Fluoxetine: relations between plasma concentration and therapeutic effects in 32 patients with major depression and treated with 20 mg/day]

The aim of this clinical study was to investigate 32 melancholic patients treated by fluoxetine (20 mg/day). The clinical examination to evaluate the antidepressant effect of fluoxetine was realized by using the HDS/MES criteria. The patients were divided into three groups (responders, partial responders with or without a relapse, non responders) according to their clinical evolution during treatment. Fluoxetine and norfluoxetine were evaluated by HPLC after 3 weeks of treatment. In the present study, 53% of the patients have a positively reaction to the 21 day's treatment. Our results showed no correlation between the psychiatric scores and the plasma concentrations of fluoxetine and norfluoxetine.

Long-term consequences of neonatal exposure to diazepam on cerebral glucose utilization, learning, memory and anxiety

The long-term consequences of neonatal exposure to diazepam (DZP) on behavioral abilities and local cerebral glucose utilization (LCGU) in 12 brain regions involved in the control of memory and anxiety were studied in adult rats. Rat pups received a daily subcutaneous injection of 10 mg/kg DZP or of the dissolution vehicle from postnatal day (P) 2 to 21. Learning and memory were tested in P60-P70 rats over 5 consecutive days in a T maze and an eight-arm maze while anxiety and reaction to novelty were tested in a two-compartment box with a two-step staircase on the enriched side. LCGU was measured in the P60 rat by the quantitative autoradiographic [14C]deoxyglucose method. In the T maze, when performed without delay between the two trials, the rate of alternation was significantly lower in DZP- than in vehicle-exposed rats on the first 2 days of testing and similar in both groups on days 3-5. In the procedure with a 30 s intertrial delay, the rate of alternation was similar in DZP- and vehicle-treated rats on all days of testing. In the eight-arm maze, DZP-treated rats were more active, i.e., entered more arms per minute than control animals. The number of arms entered before the first error was lower on day 1 and higher on day 3 in DZP- compared to vehicle-exposed rats. In the two-compartment box, DZP-treated rats crossed more often and spent more time than controls on the lower step of the staircase while control rats made more rearings and spent more time than DZP-exposed rats in the well protected corner of the box. LCGU were decreased by early DZP exposure in six regions which were mammillary body, septum, visual and prefrontal cortices, dorsomedian caudate nucleus and mediodorsal thalamus. In conclusion, postnatal DZP treatment induced at adulthood an increase in activity, a delay in task acquisition but no learning-memory impairment and reduced the level of anxiety allowing active responding to novelty. These quite subtle behavioral changes were accompanied by discrete metabolic decreases in regions mediating anxiety, reflecting a change in the level of anxiety and emotionality.

[Chronic prenatal exposure to diazepam, brain metabolism and behavior: long-term consequences in the adult rat]

The long-term consequences of a neonatal exposure to diazepam (DZP) on behavioral abilities and local cerebral metabolic rates for glucose (LCMRglc) in selected brain regions involved in the control of memory and anxiety were studied in adult rats. Rat pups received a daily subcutaneous injection of 10 mg/kg DZP or of the dissolution vehicle from postnatal day (P) 2 to 21. Learning and memory were tested in P60-P70 rats on 5 consecutive days in a T maze and an eight arm maze while anxiety and reaction to novelty were tested in a 2 compartment box with a 2 step staircase on one side. Social behavior was evaluated in a condition of restricted access to food. LCMRglcs were measured at P60 by the quantitative autoradiographic [14C]deoxyglucose method. In the T maze, when performed without delay between the 2 trials, the rate of alternation was significantly lower in DZP than in vehicle-exposed rats on the first 2 days of testing and similar in both groups on days 3-5. In the procedure with a 30 s intertrial delay, the rate of alternation was similar in DZP and vehicle-treated rats on all days of testing. In the eight arm maze, DZP-treated rats were more active, i.e. entering more arms per min than control animals. The number of arms entered before the first error was lower on day 1 and higher on day 3 in DZP compared to vehicle-exposed rats. In the 2 compartment box, DZP-treated rats crossed more often the lower step of the staircase and spent more time than controls on the 2 steps of the staircase while control rats made more rearings than DZP-exposed rats in the well protected corner of the box. LCMRglcs were decreased by early DZP exposure in several cortical regions, mammillary body, septum and dorsomedian caudate nucleus. In conclusion, an early chronic DZP treatment induces an increase in activity, only a delay but no impairment in learning and leads to a decrease in the level of anxiety and emotionality leading to an active response to novelty. These quite subtle behavioral changes are accompanied by discrete metabolic changes and probably reflect the state of hyperactivity/hyperarousal of these animals which could result from a change in the distribution, the sensitivity and/or function of GABA-BZD receptors.

Effects of aluminum chloride on normal and uremic adult male rats. Tissue distribution, brain choline acetyltransferase activity, and some biological variables

Normal and uremic adult male rats were given a daily ip injection of 20 mg Al (Al chloride)/kg for 14 d. The results indicate that Al induces a significant decrease in food ingestion, weight gain, and total protein concentration in the plasma. Compared with control animals, very high increases in Al levels were found in plasma and hepatic homogenates (about 36 and 19 times, respectively). In the brain homogenates, the Al increases were lower (about 23%). The brain cholineacetyltransferase activity was reduced: 10.6 and 14.9% in normal and uremic rats, respectively. The nephrectomy and the food restriction did not affect the total protein concentrations in plasma and the cerebral cholineacetyltransferase activity. Both were only found to be reduced in the rats treated by Al chloride.

Potential stock differences in the social behavior of rats in a situation of restricted access to food

The social behavior of outbred Long-Evans (LE) and Wistar (WI) rats was compared in a situation where access to food was particularly difficult (clearing an aquatic barrier, plus the necessity of carrying the food back to the home cage). In groups of either six WI or LE rats, only about 50% of individuals carried the food, and the others survived by attacking those that did. However, behavioral profiles associated with these acts were different in the two cases: LE carriers, contrary to WI carriers, restole some food, and LE noncarriers expressed more agonistic behavior and were more often attacked than were the WI noncarriers. Food flow and all associated, interactive behaviors were more complex in the LE than in the WI rats, indicating the likelihood of potential genetic differences in this testing situation.

Effects of postnatal aluminum exposure on biological parameters in the rat plasma

Young rats were treated by gastric intubation with aluminum chloride (100 mg Al/kg/day) and aluminum lactate (100 and 200 mg Al/kg/day) from postnatal days 5 to 14. This treatment lead to a reduction in body weight. The plasma concentrations of total proteins and albumin decreased whereas the alpha 1 globulins increased in the treated rats. The aluminum concentrations in plasma and hepatic homogenates increased particularly at 200 mg Al lactate. The reduction in average body weight could be attributed to various causes: a decreased food consumption, a transient undernutrition, a reduction of the protein synthesis in the liver. The increase of the plasma concentration of the alpha 1 globulins revealed an inflammation process.

Behavioral and metabolic consequences of neonatal exposure to diazepam in rat pups

The short-term consequences of a neonatal exposure to diazepam (DZP) on neurobehavioral development and postnatal changes in local cerebral metabolic rates for glucose (LCMRglcs) in selected regions were studied in rats. Rat pups received a daily subcutaneous injection of 10 mg/kg DZP or of the dissolution vehicle from Postnatal Day 2 (P2) to 21 (P21). DZP did not affect the static righting reflex tested at P4 but increased suspension time at P10 and time to complete a 180 degrees pivoting on an inclined plane at P9. In a locomotor coordination test performed at P20, swimming or climbing on a vertical pole was not affected by DZP while the drug impaired the ability of the rat to place its hind-paws on the horizontal platform after climbing. Likewise, DZP induced marked decreases (19-45%) in LCMRglcs in most structures studied at P10, P14, and P21. The results of the present study show that neonatal DZP treatment induces motor deficits that appear to be quite subtle, to concern mainly posture and body balance. They are not apparent in tasks such as swimming or climbing but become obvious in more difficult tasks such as achieving a horizontal quadruped position on a platform after a climbing phase. Decreases in cerebral energy metabolism appear to be mainly located in areas controlling posture and body balance and are partly correlated with the locomotor impairments recorded in the present study.

In vitro effect of aluminum chloride on choline acetyltransferase activity of the rat brain during postnatal growth

A decrease in the activity of choline acetyltransferase (ChAT) has been well documented in brains from individuals with Alzheimer's disease (AD) (Bird et al., 1983; McGeer, 1984). Decreased ChAT activity was also found in dialysis encephalopathy victims, but this reduction was less marked than that observed in AD (Yates et al., 1980). The involvement of aluminum in the etiology of AD has been proposed by some authors on the basis of abnormal concentration of aluminum in autopsied brain samples from AD patients (Krishnan et al., 1987), in the neurofibrillary tangles (Perl and Pendlebury, 1986) and the neuritic plaques (Candy et al., 1986). King (1984) hypothesized that elevated levels of aluminum contribute to the cholinergic deficits in AD. Aluminum is considered to be the causal factor in dialysis encephalopathy (Alfrey et al., 1976), particularly in young children with azotemia (Andreoli et al., 1984). Several animal studies demonstrate in vivo an aluminum effect on ChAT (Yates et al., 1980; Hofstetter et al., 1987). The distribution of the cholinergic perikarya in the rat CNS has been established immunohistochemically using antisera to ChAT (Sofroniev et al., 1982). From the basal forebrain, ChAT positive fiber bundles could be followed to the olfactory bulb, neocortex and hippocampus (Ichikawa and Hirata, 1986). This paper examines the influence of aluminum chloride at different concentrations on the activity of ChAT in homogenates from basal forebrain and neostriatum of rats during postnatal growth.

Effect of group size on social organization in rats with restricted access to food

In groups of rats subjected to a experimental design in which access to the feeder was made difficult, a behavioural differentiation developed. Some rats brought back food pellets to the cage (carrier rats) while the others stayed in the home cage (noncarrier rats). We compared the social organization underlying the adoption of these roles in groups of three and six rats. Reducing group size increased the incidence of carrier rats, leading to a smaller number of differentiated groups. However, differentiated groups seemed to adapt to the situation in the same way as the groups of six rats. In both cases, carriers could be distinguished from noncarriers by their way of obtaining food and by how food possession stopped. Moreover, behavioural variables generally exhibited better stability in small groups and noncarrier/carrier rat relations were more extensive, resulting in more typical organization. The potential use of such groups for pharmacological studies is discussed.

Effects of postnatal aluminum exposure on choline acetyltransferase activity and learning abilities in the rat

Young rats were treated by gastric intubation with aluminum lactate (0, 100, and 200 mg Al/kg/day) from postnatal days 5 to 14 to determine the treatment's influence on brain choline acetyltransferase activity and learning abilities. The results indicated that aluminum concentrations in the cerebral areas increased in parallel to plasma aluminum at the dose of 200 mg. In the same case, choline acetyltransferase activity was reduced. At postnatal days 50 and 100, the treated rats did not show alterations in their learning abilities in the 2 tests which are based on different motivations (avoidance of an aversive light or alimentary motivation) and different ways of achievement (pressing on a lever or running in a maze). A low reduction in the general activity, particularly in the radial maze test, was only observed in rats treated with 200 mg Al/kg/day.

Ingestive behaviors of the rat deficient in vasopressin synthesis (Brattleboro strain). Effect of chronic treatment by dDAVP

Spontaneous manipulator and locomotor activities, food and fluid intake have been recorded from rats suffering from a genetic lack of central vasopressin (VP) synthesis (Brattleboro strain, DI), their heterozygous litter mates (HZ) or Long Evans (LE) rats. The daily patterns of activities did not differ, except for their drinking behavior. This was mainly associated with food intake during the dark period with LE rats but was distributed equally during light and dark periods with DI rats. HZ rats showed a behavioral heterogeneity, some of them following the daily pattern of LE rats, and others, that of DI rats. The daily feeding pattern was identical in the three genotypes but the selection between two isocaloric contrasted diets was different. When they were fed ad lib, HZ and DI rats consumed less carbohydrate than LE rats, the protein intake being unchanged. On the contrary, when the DI rats were only fed during the dark period, they ate more carbohydrate than LE rats. The peripheral infusion of a V2 AVP agonist (dDAVP) restored a normal hydric balance in DI rats but failed to modify the diet selection. These data show that in the rats, the lack of central VP synthesis disturbs both the selection of diets and the efficiency of the satiety signals. These disturbances were unchanged by the peripheral VP treatment which suggested the direct involvement of the central release of the neuropeptide.

Developmental alterations in offspring of female rats orally intoxicated by aluminum lactate at different gestation periods

Pregnant rats were treated orally with aluminum lactate (400 mg Al/kg/day) during three periods of gestation to determine the treatment's influence on mortality, weight gain, neuromotor maturation, and learning abilities of their pups. No effect of treatment on litter size, mortality rate, and weight gain of pups was detected. In the negative geotaxis test, the scores of pups from females treated during the second and third weeks of gestation were diminished. In the locomotor coordination and the operant conditioning tests, significant differences in the comparison of controls vs. the three treated groups were found, indicating long-term effects of early intoxication upon the central nervous system.

Maternal behavior variations and adaptations, and pup development within litters of various sizes in Wistar rat

Variations of two maternal behavior components (time spent with litter and rapidity of pup retrieving) as well as certain physical and developmental characteristics of pups (weight, relative weight gain, and neuromotor maturation) in rats were simultaneously studied in 29 various-sized litters in which interindividual variations were not experimentally amplified. Results showed mothers' behavioral adaptations to litters' characteristics (size and weight). Time spent with young was linked to litter size, whereas rapidity of pup retrieving was related to the pups' physical characteristic. Beyond these adaptive variabilities, residual variations subsisted between mothers. These variations were determinant for differences in pup development for only one component: the time that mothers spent with their litters, while pup retrieving component variations did not have any effect.

Selective pup retrieving by mother rats: sex and early development characteristics as discrimination factors

Discrimination between own-litter pups by mother rats was studied over 14 litters, in a standardized situation eliciting maternal pup-retrieving activity. Results showed some consistency in the order in which pups of a litter were retrieved by the mother in the 4-day and 9-day tests and that this order was related to certain characteristics of the pups: 1) on Day 4 and 9, the best-developed pups of the litter (in terms of body weight and neuromotor behaviors) were first retrieved; 2) on Day 9, sex of pups became an additional discrimination factor, as males were retrieved before their female littermates. Variables included in these global discrimination factors and possible consequences of such differential mother-pups interactions are discussed.

Influence of early neonatal phenobarbital exposure on cerebral energy metabolism and behavior

The influence of an early chronic phenobarbital (PhB) exposure on local cerebral glucose utilization (LCGU) and on behavior was studied in the rat. The animals were treated from Postnatal Day 2 to Postnatal Day 35 by a daily injection of 50 mg/kg PhB or by saline and tested between 10 and 35 days for short-term effects of the drug on LCGU and between 70 and 90 days for long-term effects of PhB on LCGU and behavior. PhB induced short- and long-lasting reductions in the overall rates of LCGU in hippocampal and cerebellar areas, but no significant changes in LCGU in the different cell layers of these two cerebral areas. PhB also changed the pattern of maturation of the rates of LCGU as compared to control subjects. The barbiturate treatment induced a decrease in the exploratory behavior of PhB- as compared to saline-treated rats in the open field, as well as a significant 25% decrease in the rate of spontaneous alternation with delay. In addition, PhB-treated rats needed significantly more time than control animals to perform their trials in the nonrewarded T maze testing. However, the neonatal barbiturate exposure did not induce changes in performances of adult rats in the rewarded eight arm maze. The results of the present study show that there is no apparent correlation between the rates of energy metabolism in the hippocampus and the impairment of learning abilities of adult rats in behavioral tests related to the hippocampus.

Developmental alternations in offspring of female rats orally intoxicated by aluminum chloride or lactate during gestation

The oral treatment of pregnant rats by aluminum chloride or lactate at various doses was applied from day 1 to day 21 of gestation to determine its influence on mortality, weight evolution, and neuromotor maturation of their pups. No effect of treatment on litter size was detected, but an increased mortality appeared during the first week: treatment by aluminum lactate was less active than was an equivalent treatment by aluminum chloride. Weight was transitorily delayed, but the reversal of this effect could be attributed to the decrease of litter size. The neuromotor maturation of surviving pups treated with the two aluminum salts showed an important impairment during the first 2 weeks of postnatal life.