A biorhythmologic approach to evaluating forced swimming as an experimental model of a "depressive" state

Rhythmical structure of forced swimming was studied on rats. Reserpine (1 mg/kg, 24 h before testing), clonidine (150 mkg/kg) and prolonged repeated striatal stimulation induced behavioural depression with reorganization of swimming rhythm and increase of short cycles (less than 6 s) of immobility. After chronic administration of antidepressants (imipramine, amitriptyline, niamid, 10 mg/kg/day, during 14 days), on the contrary, the number of these cycles diminished, while the number of active swimming cycles increased. Chrono-biological "index of depression" is suggested to express more exactly behavioural depression and specific activity of antidepressants than usual registration of immobility time.     

Testosterone has antidepressant-like efficacy and facilitates imipramine-induced neuroplasticity in male rats exposed to chronic unpredictable stress

Hypogonadal men are more likely to develop depression, while testosterone supplementation shows antidepressant-like effects in hypogonadal men and facilitates antidepressant efficacy. Depression is associated with hypothalamic–pituitary–adrenal (HPA) axis hyperactivity and testosterone exerts suppressive effects on the HPA axis. The hippocampus also plays a role in the feedback regulation of the HPA axis, and depressed patients show reduced hippocampal neuroplasticity. We assessed the antidepressant-like effects of testosterone with, or without, imipramine on behavioral and neural endophenotypes of depression in a chronic unpredictable stress (CUS) model of depression. A 21-day CUS protocol was used on gonadectomized male Sprague–Dawley rats treated with vehicle, 1 mg of testosterone propionate, 10 mg/kg of imipramine, or testosterone and imipramine in tandem. Testosterone treatment reduced novelty-induced hypophagia following CUS exposure, but not under non-stress conditions, representing state-dependent effects. Further, testosterone increased the latency to immobility in the forced swim test (FST), reduced basal corticosterone, and reduced adrenal mass in CUS-exposed rats. Testosterone also facilitated the effects of imipramine by reducing the latency to immobility in the FST and increasing sucrose preference. Testosterone treatment had no significant effect on neurogenesis, though the combination of testosterone and imipramine increased PSA-NCAM expression in the ventral dentate gyrus. These findings demonstrate the antidepressant- and anxiolytic-like effects of testosterone within a CUS model of depression, and provide insight into the mechanism of action, which appears to be independent of enhanced hippocampal neurogenesis.     

Effect of combined treatment with imipramine and metyrapone on the immobility time, the activity of hypothalamo-pituitary-adrenocortical axis and immunological parameters in the forced swimming test in the rat.

Major depression is frequently associated with the hyperactivity of the hypothalamic-pituitary-adrenocortical axis, and glucocorticoid synthesis inhibitors have been shown to exert antidepressant action. The aim of the present study was to examine the effect of joint administration of metyrapone (50 mg/kg) and imipramine (5 and/or 10 mg/kg) on immobility time, plasma corticosterone concentration, the weight of spleens and thymuses and the proliferative activity of splenocytes in rats subjected to the forced swimming test--an animal model of depression. Metyrapone alone (50 mg/kg) reduced the immobility time of rats in the forced swimming test and decreased plasma corticosterone level, but did not change immunological parameters. Joint administration of metyrapone and imipramine (5 and 10 mg/kg) produced a more pronounced antidepressant-like effect than either of the drugs given alone. The forced swimming procedure significantly increased the proliferative activity of splenocytes, that parameter being reduced only by co-administration of metyrapone and imipramine. Joint administration of metyrapone and imipramine inhibited to a similar extend the corticosterone level as did treatment with metyrapone alone (about twofold); however, the plasma corticosterone level in animals treated with metyrapone and the higher dose of imipramine did not differ from the concentration of this steroid in control, not-stressed rats. The obtained results indicate that metyrapone potentiates the antidepressant-like activity of imipramine and exerts a beneficial effect on the stress-induced increase in plasma corticosterone concentration and the proliferative activity of splenocytes. These finding suggest that a combination of metyrapone and an antidepressant drug may be useful for the treatment drug-resistant depression and/or depression associated with a high cortisol level.     

Possible involvement of corticosterone and serotonin in antidepressant and antianxiety effects of chromium picolinate in chronic unpredictable mild stress induced depression and anxiety in rats

In the present study, we investigated the effects of chromium picolinate (CrP) on behavioural and biochemical parameters in chronic unpredictable mild stress (CUMS) induced depression and anxiety in rats. The normal and stressed male Swiss albino rats were administered CrP (8 and 16 μg/mL in drinking water), they received stressors for seven days (each day one stressor) and this cycle was repeated three times for 21 days. On 22nd day, behaviour assessments followed by biochemical estimations were conducted. The results showed that treatment of CrP produced significant antidepressant effect, which has been evidenced by decrease in immobility time in modified forced swimming test (FST) in chronic unpredictable mild stress (CUMS) induced depression in rats. In elevated plus maze (EPM), CrP (16 μg/mL) showed significant reduction in time spent in open arm. CrP (8 μg/mL and 16 μg/mL) also showed significant decrease in number of entries in open arm that shows antianxiety effect of CrP in CUMS rats. It was also found that CrP (8 and 16 μg/mL) significantly increased 5-HT concentration in the discrete regions of brain (cortex and cerebellum). On the other hand, the plasma corticosterone level was significantly decreased with CrP (16 μg/mL). The results suggested that increase in the concentration of 5-HT and decrease in plasma corticosterone levels could be responsible for improvement in symptoms of depression and anxiety in CUMS induced depression and anxiety in rats.     

Effect of ACTH on the imipramine- and desipramine-induced decrease in duration of immobility time as measured in a rat forced swimming test.

In a rat forced swimming test (FS), we examined the effect of repeated injections of ACTH (adrenocorticotropic hormone) for 14 days on the decreased duration of immobility time produced by imipramine and desipramine. Both imipramine (15 and 30 mg/kg, p.o.) and desipramine (15 and 30 mg/kg, p.o.) significantly decreased the duration of immobility time in the FS. On the other hand, ACTH (100 microg/kg, i.p.) alone did not affect the duration of immobility time in FS. When ACTH (100 microg/kg, i.p.) was injected for 14 days before the 15-min swim session, it counteracted the decreased duration of immobility time induced by both imipramine and desipramine. Thus, ACTH seems to play a key role in decreasing the duration of immobility time of antidepressants in this test.     

Automated experimental system capturing three behavioral components during murine forced swim test

AimsAn automated experimental system applying a commercially available video image analyzer was developed for the simultaneous detection and measurement of three behavioral components; immobility, swimming (horizontal movements) and climbing (vertical movements) that occur in the murine forced swim test (FST). The system was validated using four typical antidepressants.Main methodsSystem validity was confirmed by demonstrating no significant difference in 6 min time course of control group and imipramine-dosed group (30 mg/kg) between manual examinations and automated digital analysis for all the three behaviors (i.e., correlation coefficients were 0.96, 0.83 and 0.94 for immobility, swimming and climbing, respectively). The effects of acute single treatment with four antidepressants in clinical use, i.e., imipramine, desipramine, bupropion and fluvoxamine were evaluated at doses of 15, 30 and 60 mg/kg using the system.Key findingsIn 2–4 min time span analysis, all four antidepressants reduced immobility and increased climbing significantly, desipramine and bupropion increased swimming significantly, while imipramine and fluvoxamine did not.SignificanceThe automated experimental system enabled efficient and accurate analysis of the three murine behaviors during FST at once. Climbing could be more sensitive parameter to detect anti-depressant-like effect than immobility in this system.     

Desvenlafaxine prevents white matter injury and improves the decreased phosphorylation of the rate‐limiting enzyme of cholesterol synthesis in a chronic mouse model of depression

Serotonin/norepinephrine reuptake inhibitors antidepressants exert their effects by increasing serotonin and norepinephrine in the synaptic cleft. Studies show it takes 2–3 weeks for the mood‐enhancing effects, which indicate other mechanisms may underlie their treatment effects. Here, we investigated the role of white matter in treatment and pathogenesis of depression using an unpredictable chronic mild stress (UCMS) mouse model. Desvenlafaxine (DVS) was orally administrated to UCMS mice at the dose of 10 mg/kg/day 1 week before they went through a 7‐week stress procedure and lasted for over 8 weeks before the mice were killed. No significant changes were found for protein markers of neurons and astrocytes in UCMS mice. However, myelin and oligodendrocyte‐related proteins were significantly reduced in UCMS mice. DVS prevented the stress‐induced injury to white matter and the decrease of phosphorylated 5′‐AMP‐activated protein kinase and 3‐hydroxy‐3‐methyl‐glutaryl‐CoA reductase protein expression. DVS increased open arm entries in an elevated plus‐maze test, sucrose consumption in the sucrose preference test and decreased immobility in tail suspension and forced swimming tests. These findings suggest that stress induces depression‐like behaviors and white matter deficits in UCMS mice. DVS may ameliorate the oligodendrocyte dysfunction by affecting cholesterol synthesis, alleviating the depression‐like phenotypes in these mice.

     

Antidepressant-like effect of a Ginkgo biloba extract (EGb761) in the mouse forced swimming test: role of oxidative stress

EGb761 is a well-defined mixture of active compounds extracted from Ginkgo biloba leaves. This extract is used clinically due to its neuroprotective effects, exerted probably via its potent antioxidant or free radical scavenger action. Previous studies suggest that oxidative stress, via free radical production, may play an important role in depression and animal models for depression-like behavior. Preclinical studies have suggested that antioxidants may have antidepressants properties. The aim of this study was to investigate the antidepressant-like of EGb761 due to its antioxidant role against oxidative stress induced in the forced swimming test, the most widely used preclinical model for assessing antidepressant-like behavior. Male BALB/c mice were pretreated with EGb761 (10 mg/kg, ip) daily for 17 days followed by the forced swimming test and spontaneous locomotor activity. Animals were sacrificed to evaluate lipid peroxidation, different antioxidant enzyme activities, serotonin and dopamine content in midbrain, hippocampus and prefrontal cortex. EGb761 significantly decreased the immobility time (39%) in the forced swimming test. This antidepressant-like effect of EGb761 was associated with a reduction in lipid peroxidation and superoxide radical production (indicated by a downregulation of Mn-superoxide dismutase activity), both of which are indicators of oxidative stress. The protective effect of EGb761 is not related to excitatory or inhibitory effects in locomotor activity, and was also associated with the modulation of serotonergic and dopaminergic neurotransmission. It is suggested that EGb761 produces an antidepressant-like effect, and that an antioxidant effect against oxidative stress may be partly responsible for its observed neuroprotective effects.     

Pentadecapeptide BPC 157 positively affects both non-steroidal anti-inflammatory agent-induced gastrointestinal lesions and adjuvant arthritis in rats

Besides a superior protection of the pentadecapeptide BPC 157 (an essential fragment of an organoprotective gastric juice peptide BPC) against different gastrointestinal and liver lesions, an acute anti-inflammatory and analgetic activity was also noted. Consequently, its effect on chronic inflammation lesions, such as adjuvant arthritis, and non-steroidal anti-inflammatory agents (NSAIAs)-induced gastrointestinal lesions was simultaneously studied in rats. In gastrointestinal lesions (indomethacin (30 mg/kg sc), aspirin (400 mg/kg ig) and diclofenac (125 mg/kg ip) studies, BPC 157 (10 μg or 10 ng/kg ip) was regularly given simultaneously and/or 1 h prior to drug application (indomethacin). In the adjuvant arthritis (tail-application of 0.2 mL of Freund's adjuvant) studies (14 days, 30 days, 1 year) BPC 157 (10 μg or 10 ng/kg ip), it was given as a single application (at 1 h either before or following the application of Freund's adjuvant) or in a once daily regimen (0–14th day, 14–30th day, 14th day–1 year). Given with the investigated NSAIAs, BPC 157 consistently reduced the otherwise prominent lesions in the stomach of the control rats, as well as the lesions in the small intestine in the indomethacin groups. In the adjuvant arthritis studies, the lesion's development seems to be considerably reduced after single pentadecapeptide medication, and even more attenuated in rats daily treated with BPC 157. As a therapy of already established adjuvant arthritis, its salutary effect consistently appeared already after 2 weeks of medication and it could be clearly seen also after 1 year of application. Taking together all these results, the data likely point to a special anti-inflammatory and mucosal integrity protective effect.     

Enhancement of antidepressant potency by a potentiator of AMPA receptors

1. AMPA receptor potentiators (ARPs) exhibit antidepressant-like activity in preclinical tests (for example, the forced swim test) that are highly predictive of efficacy in humans. Unlike most currently used antidepressants, ARPs do not elevate extracellular levels of biogenic amines (e.g., 5HT, NE) in prefrontal cortex at doses that are active in the forced swim test.2. The present series of experiments examined the effects of combining the ARP, LY 392098, with biogenic amine-based antidepressants in the forced swim test. Male, NIH Swiss mice were placed in a cylinder of water and observed for attempted escape behaviors and immobility.3. LY 392098 dose-dependently decreased immobility as did a range of classical antidepressants. At doses of LY 392098 below those that decreased immobility, this compound significantly increased the potency with which fluoxetine and citalopram (SSRI antidepressants), imipramine (tricyclic antidepressant), duoxetine (norepinephrine/serotonin uptake blocker), nisoxetine (norepinephrine uptake inhibitor), and rolipram (PDE4 inhibitor) decreased immobility in the forced swim test with potency shifts upward of 5-fold (fluoxetine, imipramine, and rolipram). Likewise, ineffective doses of the traditional antidepressants potentiated the effects LY 392098 with shifts in the dose-effect functions that were 10-fold or more for citalopram, fluoxetine, imipramine, and duloxetine.4. Combined with other evidence for a role of AMPA receptors in the efficacy of antidepressants, the current data suggest that the addition of an ARP may augment the activity and perhaps the onset of the therapeutic effects of biogenic amine and second messenger-based antidepressants.     

Infantile stage of rat development in behavioral parameters of depression-like state and pain response

In the 7–8- and the 10–11-day old male rat pups born to dams exposed to an immobilization stress for the last week of pregnancy and to the dams exposed to no stress (control), behavioral parameters were studied: the level of depression in the test of forced swimming (the Porsolt’s test) and 24 h after a long pain response during inflammation (the formalin test—a subcutaneous injection of 2.5% formalin into the hind leg plantar pad). In control pups, significant age-related changes in the forced swimming were revealed: the immobility time was longer in animals of the older age group, whereas no age differences were found in parameters of the persistent inflammatory pain and in flexing + shaking behavior. The prenatal stress produced an increase in the immobility time and the flexing + shaking behavior in the 7–8-day old, but not in the 10–11-day old rat pups. This resulted in elimination of the age differences in the immobility time in the prenatally stressed animals. Thus, use of different methodic approaches has allowed revealing peculiarities in the parameters of the degree of depression and duration of the pain response at inflammation in the 7–8- and 10–11-day old rat pups, which indicates heterogeneity of the infantile development stage that, according to literature data, includes in rats the period from the 5th to the 10th postnatal days.     

Chronic cytoprotection: pentadecapeptide BPC 157, ranitidine and propranolol prevent, attenuate and reverse the gastric lesions appearance in chronic alcohol drinking rats.

Unlike severe gastric damage acutely induced by ethanol administration in rat, the ulcerogenic effect of chronic alcohol administration (3.03 g/kg b.w. or 7.28 g/kg b.w.) given in drinking water, producing liver lesions and portal hypertension, is far less investigated. Therefore, focus was on the antiulcer effect of the gastric pentadecapeptide BPC 157, GEPPPGKPADDAGLV, M.W. 1419, known to have a beneficial effect in variety of gastrointestinal lesions models (10 microg or 10 ng/kg b.w. i.p. or i.g.), ranitidine (10 mg/kg b.w. i.g.) and propranol (10 mg/kg b.w. i.g.) or saline (5 ml/kg b.w. i.p./i.g.; control). They were given once daily (1) throughout 10 days preceding alcohol consumption, (2) since beginning of alcohol drinking till the end of the study, (3) throughout the last month of alcohol consumption, 2 months after alcohol drinking had been initiated. Gastric lesions were assessed, at the end of 3 months drinking [(1), (2)] or with respect to therapeutic effect of medication before medication or at the end of therapy. Pentadecapeptide BPC 157, ranitidine and propranolol may prevent gastric lesion development if given prophylactically, before alcohol drinking. Likewise, they attenuate the lesion appearance given once daily throughout the drinking period. Importantly, when given therapeutically, they may antagonize otherwise pertinent lesion presence in stomach mucosa of the drinking rats. Thus, these results demonstrate that pentadecapeptide BPC 157, ranitidine and propranol may prevent, attenuate or reverse the gastric lesions appearance in chronically alcohol drinking rats, and may be used for further therapy, while the other studies showed that their effect (except to ranitidine) is parallel with their beneficial effect on liver lesion and portal hypertension.     

The selective glucocorticoid receptor antagonist CORT 108297 decreases neuroendocrine stress responses and immobility in the forced swim test

Pre-clinical and clinical studies have employed treatment with glucocorticoid receptor (GR) antagonists in an attempt to limit the deleterious behavioral and physiological effects of excess glucocorticoids. Here, we examined the effects of GR antagonists on neuroendocrine and behavioral stress responses, using two compounds: mifepristone, a GR antagonist that is also a progesterone receptor antagonist, and CORT 108297, a specific GR antagonist lacking anti-progestin activity. Given its well-documented impact on neuroendocrine and behavioral stress responses, imipramine (tricyclic antidepressant) served as a positive control. Male rats were treated for five days with mifepristone (10 mg/kg), CORT 108297 (30 mg/kg and 60 mg/kg), imipramine (10 mg/kg) or vehicle and exposed to forced swim test (FST) or restraint stress. Relative to vehicle, imipramine potently suppressed adrenocorticotropin hormone (ACTH) responses to FST and restraint exposure. Imipramine also decreased immobility in the FST, consistent with antidepressant actions. Both doses of CORT 108297 potently suppressed peak corticosterone responses to FST and restraint stress. However, only the higher dose of CORT 108297 (60 mg/kg) significantly decreased immobility in the FST. In contrast, mifepristone induced protracted secretion of corticosterone in response to both stressors, and modestly decreased immobility in the FST. Taken together, the data indicate distinct effects of each compound on neuroendocrine stress responses and also highlight dissociation between corticosterone responses and immobility in the FST. Within the context of the present study, our data suggest that CORT 108297 may be an attractive alternative for mitigating neuroendocrine and behavioral states associated with excess glucocorticoid secretion.     

Synthesis and antidepressant-like activity evaluation of sulphonamides and sulphonyl-hydrazones

In this study a series of sulphonamides and sulphonyl hydrazones of maleimide, naphthalimide and phthalimide derivatives was synthesized. The antidepressant effect of these compounds was evaluated by the forced-swimming test in mice. The behavioural parameter observed in this test is a reduction in the immobility time, which is indicative of antidepressant activity. All compounds, except 8, 11 and 24, were active as antidepressants. The most active compound was the sulphonyl-hydrazone 10 which showed an activity of around 72.02% at 60 mg/kg, it thus being more active than imipramine (10mg/kg, ip), a commercial antidepressant. Other important results were obtained for the benzylnaphthalimide derivatives, the sulphonamides 21 and 22 showing activity of 64% at 10mg/kg, also being more active than imipramine. These results indicate that the sulphonamides and sulphonyl-hydrazone cyclic imide derivatives are potential compounds for use in the designing of new candidates for the treatment of depression.     

二甲双胍对慢性应激大鼠抑郁行为的影响

目的:观察二甲双胍对慢性不可预测性温和应激大鼠抑郁行为的影响。方法:40只雄性SD大鼠随机分为4组(n=10):对照组(CON组)、二甲双胍组(MET组)、模型组(CUMS组)、模型+二甲双胍组(CUMS+MET组),采用慢性不可预测性温和应激(CUMS)方法,用3周时间建立大鼠抑郁模型。造模完成后,两个二甲双胍组腹腔注射二甲双胍(100mg/kg),对照组和模型组注射等量的生理盐水,每天1次,连续2周。之后检测大鼠体重增长变化、糖水嗜好、强迫游泳和悬尾不动实验、旷场实验等大鼠行为学的改变,采用尼氏染色观察大鼠海马形态结构变化。结果:与对照组比较,CUMS组大鼠体重增长明显减慢(P<0.05),糖水偏爱率明显降低(P<0.05),强迫游泳和悬尾不动实验中不动时间明显延长(P<0.05),旷场实验中自发活动明显减少(P<0.05),大鼠海马的形态结构有所变化,证实CUMS抑郁模型建立成功。与CUMS组比较,二甲双胍处理后对大鼠的体重无明显影响,但能明显改善CUMS抑郁模型大鼠的糖水摄入、不动时间和自发活动(P<0.05),并能修复CUMS大鼠海马的异常形态结构变化。结论:二甲双胍对CUMS诱导的大鼠抑郁行为具有明显的改善作用,为临床糖尿病并发抑郁症的患者提供新的治疗手段。     

Association Between Na<Superscript>+</Superscript>,K<Superscript>+</Superscript>-ATPase Activity and the Vulnerability/Resilience to Mood Disorders induced by Early Life Experience

There is increasing evidence that early life events can influence neurodevelopment and later susceptibility to disease. Chronic variable stress (CVS) has been used as a model of depression. The objective of this study was to evaluate the interaction between early experience and vulnerability to chronic variable stress in adulthood, analyzing emotional, metabolic and neurochemical aspects related to depression. Pups were (1) handled (10 min/day) or (2) left undisturbed from day 1 to 10 after birth. When the animals reached adulthood, the groups were subdivided and the rats were submitted or not to CVS, which consisted of daily exposure to different stressors for 40 days, followed by a period of behavioral tasks, biochemical (plasma corticosterone and insulin sensitivity) and neurochemical (Na⁺,K⁺-ATPase activity in hippocampus, amygdala and parietal cortex) measurements. Neonatally-handled rats demonstrated shorter immobility times in the forced swimming test, independently of the stress condition. There was no difference concerning basal corticosterone or insulin sensitivity between the groups. Na⁺,K⁺-ATPase activity was decreased in hippocampus and increased in the amygdala of neonatally-handled rats. CVS decreased the enzyme activity in the three structures, mainly in the non-handled group. These findings suggest that early handling increases the ability to cope with chronic variable stress in adulthood, with animals showing less susceptibility to neurochemical features associated with depression, confirming the relevance of the precocious environment to vulnerability to psychiatric conditions in adulthood.     

Characteristics of the combined action of melatonin and imizin on the structure of forced swimming and the circadian rhythm

Acute administration of melatonin (10 mg/kg) produced a depressed effect on the mice behavior. But it's injection after chronic imipramine (10 mg/kg/day, 2 weeks) potentiated antidepressant ability and shortened the duration of immobility in the structure of swimming. In rats, which had a high amplitude of circadian rest-activity rhythm, melatonin produced imipramine effect on circadian mobility, but potentiated antidepressant action in animals with low initial level of locomotor activity.     

Alarin-induced antidepressant-like effects and their relationship with hypothalamus–pituitary–adrenal axis activity and brain derived neurotrophic factor levels in mice

Alarin is a newly identified member of the galanin family of peptides. Galanin has been shown to exert regulatory effects on depression. Similar to galanin in distribution, alarin is also expressed in the medial amygdala and hypothalamus, i.e., regions interrelated with depression. However, it remains a puzzle whether alarin is involved in depression. Accordingly, we established the depression-like mouse model using behavioral tests to ascertain the possible involvement of alarin, with fluoxetine as a positive control. With the positive antidepressant-like effects of alarin, we further examined its relationship to HPA axis activity and brain-derived neurotrophic factor (BDNF) levels in different brain areas in a chronic unpredictable mild stress (CUMS) paradigm. In the acute studies, alarin produced a dose-related reduction in the immobility duration in tail suspension test (TST) in mice. In the open-field test, intracerebroventricular (i.c.v.) injection of alarin (1.0 nmol) did not impair locomotion or motor coordination in the treated mice. In the CUMS paradigm, alarin administration (1.0 nmol, i.c.v.) significantly improved murine behaviors (FST and locomotor activity), which was associated with a decrease in corticotropin-releasing hormone (CRH) mRNA levels in the hypothalamus, as well as a decline in serum levels of CRH, adrenocorticotropic hormone (ACTH) and corticosterone (CORT), all of which are key hormones of the HPA axis. Furthermore, alarin upregulated BDNF mRNA levels in the prefrontal cortex and hippocampus. These findings suggest that alarin may potentiate the development of new antidepressants, which would be further secured with the identification of its receptor(s).     

The comparison of immobility time in experimental rat swimming models

Rat swimming models have been used in studies about stress and depression. However, there is no consensus about interpreting immobility (helplessness or adaptation) in the literature. In the present study, immobility time, glucose and glycogen mobilization, corticosterone and the effect of desipramine and diazepam were investigated in two different models: swimming stress and the forced swimming test. Immobility time was lower in swimming stress than in the forced swimming test. Both swimming models increased corticosterone levels in comparison with control animal levels. Moreover, swimming stress induced higher corticosterone levels than the forced swimming test did [F(2,14)=59.52; p<0.001]. Liver glycogen content values differed from one another (swimming stress相似文献   

Cysteamine-colon and cysteamine-duodenum lesions in rats. Attenuation by gastric pentadecapeptide BPC 157, cimetidine, ranitidine, atropine, omeprazole, sulphasalazine and methylprednisolone.

Recently, we showed cysteamine-duodenal lesions without gastric acid, since they were induced also in gastrectomized rats, as in naive rats, and they were inhibited by the novel stomach pentadecapeptide BPC 157 as well as standard antiulcer drugs (i.e. cimetidine, ranitidine, omeprazole, bromocriptine, atropine). Therefore, as an advantage of considering cysteamine as a directly acting cytotoxic agent and mentioned agents as direct cytoprotective agents, the present focus was on the ulcerogenic effect of cysteamine and protective effect of gastroduodenal antiulcer agents outside upper gastrointestinal tract (i.e. in colon). Intrarectal administration of the cysteamine (200 or 400 mg/kg b.w) produced severe colon lesions (i.e. transmural inflammation with serosal involvement) in rats (30 min-72 h-experimental period), apparently distinctive from smaller lesions after non-specific irritant enema [diluted HCl solution, pH 3.8 (adjusted to pH of cysteamine solution (pH 3.8)]. All of the tested antiulcer agents were applied simultaneously with cysteamine enema (8 cm from the anus, in a volume of the 1.0 ml/rat) intraperitoneally (i.p.), intragastrically (i.g.) or intrarectally (i.r.). Pentadecapeptide BPC 157 (10 microg or 10 ng/kg b.w.), given in either regimen, previously shown to have, besides others, a particular beneficial activity just in the intestinal mucosa, inhibited these cysteamine colon lesions (assessed after 30 min, 60 min, 180 min, 24 h, 48 h, 72 h following cysteamine in a dose of either 200 or 400 mg/kg i.r.). Cysteamine-colon lesions were also attenuated by standard antiulcer agents (mg/kg b.w.), given i.p., i.g., or i.r., such as ranitidine (10), cimetidine (50), omeprazole (10), atropine (10), together with methylprednisolone (1), and sulphasalazine (50, i.r.), assessed 30 min following application of 200 mg of cysteamine. Finally, standard cysteamine duodenal lesions (assessed 24 h after a subcutaneous application of 400 mg/kg of cysteamine) were also attenuated by these agents application (given in the same doses, i.p., 1 h before cysteamine), with only exception to sulphasalazine. Thus, the extended cysteamine specific ulcerogenic effect, cysteamine colon/duodenum lesion-link and an extenuation of agents protection from upper to lower part of gastrointestinal tract (i.e. stomach pentadecapeptide BPC 157, standard antiulcer agents, cimetidine, ranitidine, atropine, omeprazole) and vice versa (remedies for inflammatory bowel disease) evidenced in the present study may be potentially important for both further experimental and clinical research.