Low oxygen tension enhances hepatitis C virus replication.

Low oxygen tension exerts a significant effect on the replication of several DNA and RNA viruses in cultured cells. In vitro propagation of hepatitis C virus (HCV) has thus far been studied under atmospheric oxygen levels despite the fact that the liver tissue microenvironment is hypoxic. In this study, we investigated the efficiency of HCV production in actively dividing or differentiating human hepatoma cells cultured under low or atmospheric oxygen tensions. By using both HCV replicons and infection-based assays, low oxygen was found to enhance HCV RNA replication whereas virus entry and RNA translation were not affected. Hypoxia signaling pathway-focused DNA microarray and real-time quantitative reverse transcription-PCR (qRT-PCR) analyses revealed an upregulation of genes related to hypoxic stress, glycolytic metabolism, cell growth, and proliferation when cells were kept under low (3% [vol/vol]) oxygen tension, likely reflecting cell adaptation to anaerobic conditions. Interestingly, hypoxia-mediated enhancement of HCV replication correlated directly with the increase in anaerobic glycolysis and creatine kinase B (CKB) activity that leads to elevated ATP production. Surprisingly, activation of hypoxia-inducible factor alpha (HIF-α) was not involved in the elevation of HCV replication. Instead, a number of oncogenes known to be associated with glycolysis were upregulated and evidence that these oncogenes contribute to hypoxia-mediated enhancement of HCV replication was obtained. Finally, in liver biopsy specimens of HCV-infected patients, the levels of hypoxia and anaerobic metabolism markers correlated with HCV RNA levels. These results provide new insights into the impact of oxygen tension on the intricate HCV-host cell interaction.

Effect of donepezil in Alzheimer disease can be measured by a computerized human analog of the Morris water maze.

BACKGROUND: Drug development for Alzheimer disease (AD) is challenged by the success in animal models tested in the Morris water maze (MWM) and the subsequent failures to meet primary outcome measures in phase II or III clinical trials in patients. The human variant of MWM (hMWM) enables us to examine allocentric and egocentric navigation as in the MWM. OBJECTIVE: It was the aim of this study to examine the utility of a computerized hMWM to assess the effects of donepezil in mild AD. METHODS: Donepezil 5 mg/day was started after initial hMWM testing in the treated group (n = 12), and after 28 days, the dose was increased to 10 mg/day. The performance after 3 months was compared to that of a non-treated group (n = 12). RESULTS: Donepezil stabilized or improved the spatial navigation performance after 3 months, especially in the allocentric delayed recall subtask (p = 0.014). CONCLUSIONS: The computerized hMWM has the potential to measure the effects of donepezil in mild AD. It is a sensitive cognitive outcome measure in AD clinical trials.

Elevated levels of soluble total and hyperphosphorylated tau result in early behavioral deficits and distinct changes in brain pathology in a new tau transgenic mouse model.

Tauopathies, characterized by hyperphosphorylation and aggregation of tau protein, include frontotemporal dementias and Alzheimer's disease. To explore disease mechanisms and investigate potential treatments, we generated a transgenic (tg) mouse line overexpressing human tau441 with V337M and R406W mutations. Biochemical characterization of these TMHT (Thy-1 mutated human tau) mice showed a significant increase in human transgene expression relative to endogenous murine tau by Western blot and multi-array immunosorbent assay. Only soluble total tau and phosphorylated tau (ptau at residue Thr(181), Ser(199), Thr(231) and Thr(235)), but not insoluble total tau and ptau were increased. Application of the Phospho-Tau SRM assay revealed that phosphorylation at Ser(396) and Ser(404) in soluble tau in the presence of the R406W mutation was at baseline levels in the cortex of TMHT mice compared to non-tg littermates. Histological analyses showed a progressive increase in human tau protein in the amygdala over age, while hippocampal tau levels remained constant from 2 months onwards. Behavioral testing of TMHT mice in the Morris water maze revealed a distinct progressive spatial learning impairment starting already at 5 months of age. Furthermore, we showed that the TMHT mice have early olfactory deficits. These impairments are unbiased by any motor disturbance or lack of motivation. Our results prove that combination of the V337M and R406W mutations of tau accelerates human tau phosphorylation and induces tau pathology as well as cognitive deficits, making this model a suitable tool for basic research on tau as well as in vivo drug testing.

Experimental infection of chickens with Histomonas meleagridis confirms the presence of antibodies in different parts of the intestine.

Specific pathogen-free chickens were infected with a clonal culture of the protozoan parasite, Histomonas meleagridis. Severe lesions were found within the caeca of all birds euthanized at 7 and 14 days post-infection (d.p.i.). Following necropsy of birds, intestinal samples were taken to establish ex vivo tissue cultures to determine the IgG, IgA and IgM antibody levels in the supernatants before and after incubation with a recently established ELISA. Presence of antibodies was also determined in the sera and first optical density values for IgG above the cut-off were detected at 14 d.p.i. IgA levels remained low in the serum with a small peak 4 weeks p.i., a phenomenon also found for IgM. The intestinal tissue samples showed very strong immunological reactions in the parasitized caeca with an initial peak of IgM, high levels of IgG and a continuous increase of IgA. In the duodena and jejuna, IgA values reached similar high levels as those obtained in the caeca, whereas IgG and IgM increased only slightly.

Oral vaccination of 1-day-old turkeys with in vitro attenuated Histomonas meleagridis protects against histomonosis and has no negative effect on performance.

One-day-old turkey poults were vaccinated against histomonosis (syn. histomoniasis) via the oral route by application of in vitro attenuated Histomonas meleagridis. Subsequently, two different groups composed of 14 birds each were challenged cloacally with highly virulent histomonads after 2 or 4 weeks. Two additional groups of non-vaccinated birds were infected with the challenge inoculum at the same time points. In addition, a group of 19 birds, of which 14 were vaccinated but not challenged, were kept for clinical and serological examinations. Non-vaccinated and non-challenged birds (n=10) represented the negative control group. All non-vaccinated but infected birds and 10 out of 14 vaccinated turkeys challenged 2 weeks post vaccination (w.p.v.) contracted severe histomonosis. Turkeys challenged 4 w.p.v. and all remaining birds used in this experiment did not show any pathognomonic clinical signs. In addition, no adverse effect regarding the weight gain could be observed in birds that were vaccinated but not challenged. The excretion of attenuated and virulent live histomonads was observed very infrequently by re-isolation, but transmission to in-contact birds was very efficient. Presence of antibodies was first noticed 3 w.p.v. and antibody levels remained above the cut-off value until termination of the experiment at 16 w.p.v. The present experiment demonstrates for the first time the potential efficacy of in vitro attenuated histomonads used as an orally applied vaccine to 1-day-old turkeys for protection against fatal histomonosis without affecting performance.

Randomized, crossover, single-blind, placebo-controlled, human pharmacology clinical trial with desoxypeganine, a new cholinesterase and selective MAO-A inhibitor: multiple-dose pharmacokinetics.

UNLABELLED: Desoxypeganine, a naturally occurring alkaloid, is being developed for its potential utility in the pharmacological treatment of alcohol abuse to reduce craving and depression in alcohol abusers, and might also be useful as a smoking cessation aid. During the preclinical development it was characterized as a cholinesterase inhibitor, acting preferentially on butyrylcholinesterase, and as a selective inhibitor of monoamine oxidase A but not monoamine oxidase B. OBJECTIVE: The aim of the present human pharmacology clinical trial was to assess the oral bioavailability, pharmacokinetic profile and tolerability of desoxypeganine, administered in a multiple-dose regimen to healthy volunteers. SUBJECTS AND METHODS: Eighteen healthy adult volunteers of both sexes received placebo, 50 mg and 100 mg desoxypeganine (b.i.d. for 3 days) in a single-blind, crossover, randomized manner. Main pharmacokinetic parameters after single and multiple doses were estimated. Clinical tolerability and clinical laboratory safety, including effect on QTc interval, were assessed. RESULTS: Non-compartmental estimations of Cmax, AUC, tmax, t1/2 and MRT at 12-h intervals are given. No significant dose effect was observed in tmax, t1/2 and MRT. Cmax and AUC are approximately double with the dose of 100 mg comparing with the dose of 50 mg. A significant increase (p < 0.05) on Cmax and AUC was also obtained with the highest dose administered in comparison with the lowest one, revealing a slight but clinically insignificant accumulation. Steady state of drug concentration was reached in both genders during the study period. Plasma protein binding of desoxypeganine amounted to approximately 18%. No severe adverse events were recorded and none of the subjects suffered from any adverse event that led to withdrawal from the study. Most frequently recorded adverse event was dizziness. No significant effects of desoxypeganine on vital signs, laboratory parameters or QTc interval were observed. CONCLUSIONS: The present clinical trial describes the pharmacokinetic profile of two doses of desoxypeganine, administered orally in multiple dose to healthy volunteers. The drug was well tolerated without any severe clinical, clinical laboratory, or ECG adverse events being recorded.

Establishing an indirect sandwich enzyme-linked-immunosorbent-assay (ELISA) for the detection of antibodies against Histomonas meleagridis from experimentally infected specific pathogen-free chickens and turkeys.

No serological method suitable for large screening of antibodies against Histomonas meleagridis in poultry is available so far, the objective targeted in the present investigation. Consequently, an ELISA was developed as a suitable tool for this purpose. Investigating serum samples from non-infected specific pathogen-free (spf) chickens and commercial turkeys a high-background signal was noticed when ELISA plates were directly coated with purified parasitic cells. This signal was significantly reduced by coating the plates with a polyclonal rabbit antibody, raised against histomonads, prior to the addition of the antigen. Adopting this approach five antigen preparations were compared and a high reproducibility could be demonstrated reflected by a very low coefficient of variation of 5.3% and 1.7% for the chicken and turkey sera, respectively. After this initial development all further experiments were carried out with one set of plates and the same antigen preparation. Investigating chicken sera obtained from birds infected at 14 days of life, OD values above a predetermined cut-off value were observed 2 weeks post-infection and a rise of IgG antibodies was noticed until 6 weeks post-infection, when the experiment was terminated. Non-protected turkeys infected at 6 weeks of age displayed an increasing IgG response until 14 days post-infection, prior to the death of animals due to histomonosis. In comparison, the majority of turkeys vaccinated with attenuated histomonads, obtained through prolonged passaging and challenged 4 weeks later with virulent parasites, displayed a demonstrable antibody response after the challenge only. Antibody titres increased until 4 weeks post-challenge when the birds were killed and the study was terminated. Altogether, the developed indirect sandwich ELISA proved to be a quick and efficient method to detect IgG antibodies against H. meleagridis in sera of experimentally infected chickens and turkeys and will be a helpful tool to obtain more insights into the epidemiology of the parasite and the immune response of its hosts.

Longitudinal multimodal imaging in mild to moderate Alzheimer disease: a pilot study with memantine.

OBJECTIVE: To study the feasibility of multimodal neuroimaging in mild to moderate Alzheimer disease (AD) and to estimate the size of possible treatment effects of memantine on potential functional, structural and metabolic biomarkers of disease progression. METHODS: In this randomised, double-blind, placebo-controlled pilot study, 36 patients with moderate AD received 52 weeks of memantine (20 mg/day) or placebo. Patients were re-evaluated after 26 and 52 weeks to measure the change from baseline in several outcome measures including global and regional glucose metabolism, total brain and hippocampal volumes, as well as chemical shift imaging-derived global and regional N-acetylaspartate and myoinositol concentrations. RESULTS: In the total population, global glucose metabolism decreased by 2.3% (p<0.01), total brain volume by 2.1% (p<0.001) and hippocampal volume by 2.7% (p<0.01) after 52 weeks. Chemical shift imaging (CSI) spectra were severely affected by patient-induced artefacts and highly variable. Patients receiving memantine showed less decline in glucose metabolism in all brain areas than patients on placebo. Their loss of hippocampal volume was substantially smaller (2.4% vs 4.0%). No between-group differences were seen for changes in total brain volume. CONCLUSIONS: The results support the use of multimodal imaging including MRI and positron emission tomography (PET) to monitor the progression of moderate AD. CSI yielded unreliable longitudinal results. The data suggest that memantine has potentially protective effects in AD and they can be used for planning larger confirmatory studies on the cerebral effects of memantine.

The role of alpha-synuclein in neurodegenerative diseases: a potential target for new treatment strategies?

Alpha-synuclein (AS) is the main constituent of Lewy bodies. There is an ongoing discussion if overexpression is already dangerous, or if toxicity is subjected to oligomers, protofibrils or mature aggregates. The facts that the central hydrophobic part of AS is also a constituent of amyloid plaques in Alzheimer's disease (AD) and that a majority of patients have Lewy bodies and Lewy neurites in specific brain areas raised our interest in the contribution of AS to AD pathogenesis. The N-terminal amino acid sequence 1-15 of beta-synuclein (BS) seems to be a natural antiaggregation factor for AS. We synthesized a library with different sequence variations. Several of these peptides displayed neuroprotective activity in tissue culture models of neurodegeneration induced by oxidative stress or beta-amyloid 1-42. In spite of the fact that these peptides have a short half-life, a significant in vivo reduction in brain plaque load and improvement of behavior was demonstrated in amyloid precursor protein transgenic mice after intranasal treatment for 2 months. KEGV, the shortest sequence, was also active after intraperitoneal application. The in vitro effects cannot be explained by the antiaggregatory potential, but most likely by interaction of BS derivates with antiapoptotic PI3/Akt or antioxidative pathways. The possibility that BS-derived peptidomimetics act as neuroprotectants and prevent protein misfolding suggests therapeutic usefulness.

Phase I clinical trial with desoxypeganine, a new cholinesterase and selective MAO-A inhibitor: tolerance and pharmacokinetics study of escalating single oral doses.

Desoxypeganine (DOP) is a natural alkaloid that has been characterized as a cholinesterase inhibitor and a selective inhibitor of monoamine oxidase A. DOP has been investigated for its potential utility in the pharmacological treatment of alcohol abuse and as a smoking cessation aid. The aim of this clinical trial was to evaluate the tolerance and single-dose pharmacokinetic profile of DOP in healthy human volunteers. The study was an open-label, dose-escalation, phase I clinical trial involving the administration of increasing single oral doses of DOP (50, 100, 150 and 200 mg). The study was conducted according to the Declaration of Helsinki and Good Clinical Practice. Eighteen healthy adult volunteers (8 males and 10 females, age ranging 20-30 years) were recruited. DOP was administered sequentially, escalating in single doses of 50, 100, 150 and 200 mg in four experimental sessions with a washout period of at least 1 week between them. Progress to the next dose was allowed only if the previous dose was tolerated. Pharmacokinetic parameters were determined using noncompartmental methods. Clinical and analytical safety was assessed throughout the study, and QTc intervals were measured at regular intervals. The main pharmacokinetic parameters and renal excretion are described. No serious adverse events were registered, and none of the subjects discontinued the study because of lack of tolerance. All the adverse events recorded were mild to moderate and increased with the dose. The ECG measurements revealed that even at a higher dose, the QTc interval remained below the safety threshold. In summary, this first phase I study indicates that DOP has linear and dose-proportional pharmacokinetics, satisfactory oral bioavailability and plasma half-life and renal excretion. Also, DOP has shown an adequate safety profile that allows the continuation of clinical development.

Is alpha-synuclein pathology a target for treatment of neurodegenerative disorders?

Alpha-synuclein is the main constituent of intra-neuronal Lewy bodies, which are characteristic of Parkinson's disease, but aggregates are also found as axonal inclusions. Alpha-synuclein pathology is found together with beta-amyloid plaques and neurofibrillary tangles in Alzheimer's disease and other neurodegenerative disorders. In spite of the fact that the biological function of this synaptic protein is not known so far, there is an increasing body of evidence indicating an interaction with amyloid peptides, but also with tau-hyperphosphorylation. A high proportion of alpha-synuclein purified from Lewy bodies is phosphorylated on Ser129. There are still different opinions about the toxicity of the alpha-synuclein aggregates. Alpha-synuclein seems to influence different intracellular signaling pathways which are in direct relation to defense mechanisms against reactive oxygen species or apoptosis. It is obvious that overproduction of alpha-synuclein, but also different mutations, are inducing the formation of aggregates. Because of the possible link to neurodegeneration, different attempts have been made to counteract alpha-synuclein aggregation. An interesting approach is utilizing beta-synuclein, a biological factor, with an aminoacid sequence closely resembling that of alpha-synuclein. Proof of concept studies indicated that overexpression of beta-synuclein is able to counteract alpha-synuclein aggregation in a transgenic animal model, while also ameliorating functional deficits. As an alternative approach, the use of low molecular beta-synuclein N-terminal peptide derivatives has been considered. Several of these structures displayed clear neuroprotective activities in tissue culture models of neurodegeneration, including beta-amyloid toxicity. Therefore it has been speculated that these compounds might have a broad therapeutic efficacy in different neurodegenerative disorders. A proof of concept study in hAPP-transgenic animals resulted in a highly significant decrease in beta-amyloid plaque load, an increase in soluble beta-amyloid peptides and a decrease in insoluble forms. There was also significant improvement of cognitive deficits in this APP transgenic mouse model following intranasal but also peripheral treatment with three of these compounds. From this study it is concluded that the observed effects of the peptides derived from beta-synuclein N-terminus are depending on both, a direct interaction with aggregation of proteins, but also with stimulation of anti-apoptotic and anti-oxidative intracellular signaling pathways.

Neuropeptide dietary supplement N-PEP-12 enhances cognitive function and activates brain bioelectrical activity in healthy elderly subjects.

N-PEP-12 is a dietary supplement consisting of neuropeptides and amino acids. In animal experiments, the compound has been shown to enhance cognitive function and reduce neurodegenerative events associated with aging. In this study, we investigated the effects of a single oral dose of N-PEP-12 (180 mg) on brain bioelectrical activity and cognitive performance in healthy elderly subjects. N-PEP-12 induced a significant (p < 0.05) increase in relative alpha-activity power 6 h after administration. This enhancement was accompanied by a generalized decrease in slow Delta-activity. Significant improvement in memory performance subtests was also seen 6 h after N-PEP-12 administration in some but not in all tests. Taken together, these data suggest that N-PEP-12 might be a reliable dietary supplement to be investigated for improving and, perhaps, maintaining brain function among healthy older adults.

Acute effects of amiodarone on ultrastructure and electrical activity of isolated guinea pig hearts.

STUDY OBJECTIVE: The aim was to evaluate the effects of tissue concentration of amiodarone on ultrastructure and electrical activity in isolated spontaneously beating Langendorff perfused guinea pig hearts. DESIGN: Group 1: The influence of 10 microM amiodarone over a period of 1 h in a non-recirculated perfusate on conduction intervals, heart rate, creatine kinase concentration in the coronary effluent, coronary flow, and drug accumulation was determined. Group 2: Ultrastructural changes after 30 min and 60 min perfusion with amiodarone were examined. Group 3: Cardiac refractoriness was evaluated following 30 min and 60 min of perfusion with amiodarone. EXPERIMENTAL PREPARATIONS: Isolated hearts of guinea pigs (200-300 g) were used: group 1, n = 6 animals; group 2, n = 3 for each time span; and group 3, n = 6 for each time span. MEASUREMENTS AND MAIN RESULTS: A steady state for the effects of amiodarone on atrioventricular and intraventricular conduction [+31(SEM 5)%, p less than 0.01% +47(12)%, p less than 0.01, respectively] and on heart rate [-30(9)%, p less than 0.01] was reached after 15 min, and on His bundle conduction [+38(17)%, p less than 0.01] after 30 min. QT duration was not affected throughout the duration of the experiment. Cardiac refractoriness was significantly prolonged following 30 min perfusion with 10 microM amiodarone, and was further significantly increased following 60 min perfusion. Amiodarone tissue concentration increased to 365(39) nmol.g-1 wet weight, and this was accompanied by an increase in creatine kinase concentration in the coronary effluent. Coronary flow stayed constant throughout the whole experiment. At the end of the experiment electron microscopic examination of the myocardium of the left ventricle showed accumulation, fusion, and vacuolisation of mitochondria, and perinuclear oedema. CONCLUSIONS: These observations suggest that amiodarone, as well as exerting acute electrophysiological effects, creates ultrastructural changes which probably contribute to its effectiveness in arrhythmias caused by scarred myocardium.

In vivo upregulation of the blood-brain barrier GLUT1 glucose transporter by brain-derived peptides.

Glucose is the critical metabolic fluid for the brain, and the transport of this nutrient from blood to brain is limited by the blood-brain barrier (BBB) GLUT1 glucose transporter. The expression of the BBB-GLUT1 gene is augmented in brain endothelial cultured cells incubated with brain-derived trophic factors and the brain-derived peptide preparation Cerebrolysin (C1, EBEWE, Austria). The aim of the present investigation was to determine if C1 induces similar changes in the expression of the BBB-GLUT1 gene following its administration to rats in vivo. The BBB glucose transporter activity was investigated with the intracarotid artery perfusion technique using [3H]diazepam as cerebral blood flow marker. The acute or chronic administration of C1 markedly increased the brain permeability surface area of D-[14C]glucose compared to controls (D-[14C]glucose/[3H]diazepam ratio, 1.6- to 1.9-fold increase in frontal cortex, P < 0.05). Increased activity of the BBB glucose transporter was correlated with a significant rise in the abundance of the BBB-GLUT1 protein measured by both Western blot analysis and immunocytochemistry, and with a decrease in the transcript levels of this transporter. Data presented here demonstrate that the in vivo administration of Cl increases the transport of glucose from blood to brain via BBB-GLUT1 gene expression.

Early postnatal treatment with peptide preparations influences spatial navigation of young and adult rats.

The brain derived peptidergic drug Cerebrolysin has been found to support the survival of neurons in vitro and in vivo. Positive effects on learning and memory have been demonstrated in various animal models and also in clinical trials. In the present study the effects of early postnatal administration of Cerebrolysin (Cere, 10 mg/ml peptides) or an enriched peptide fraction of Cere (E021, 80.6 mg/ml peptides) were investigated in young, young adult, and old adult rats. Rat pups received the drugs or saline for control on postnatal days 1-7. The animals were tested in the Morris water maze (MWM) either in the 5th week, in the 3rd or the 16th month of life for 6 consecutive days (test days 1-6), eight trials per day. In order to prevent the chance finding of the hidden platform, the rigid underwater platform was replaced by a collapsible island, resting at the bottom of the pool. The platform was raised when the animal stayed in the target area for 2 s. In the young and young adult rats both Cere and E021 treated rats showed shorter escape latencies than saline treated controls on all 6 test days. No significant differences in the swimming speed were evaluated for the young rats, although in 3-month-old drug-tested animals a moderate increase of the swimming speed was investigated. For 16-month-old animals no significant differences in either escape latencies or swimming speed was found. Summarizing, early postnatal application of Cere or E021 improved the spatial learning and memory of young rats and led to long-lasting behavioural effects at least up to 3 months after treatment.

Postnatal administration of two peptide solutions affects passive avoidance behaviour of young rats.

The effects of two subcutaneously injected peptide solutions CERE (100 mg/kg b. wt.) and E021 (1 mg/kg b. wt.) and of 0.9% saline on passive avoidance reaction (PAR) of young rats were examined. Animals were trained and tested in a step-through avoidance task using a footshock of 0.5 mA or 1 mA. Step-through latencies were observed up to 200 s and from these data the percentage of good learners (latency = 200 s) and bad learners (latency < 200 s) was calculated. Two experimental schedules were performed (n > 6). In Expt. 1 rat pups were chronically treated with the substances within the first 7 days after birth. In Expt. 2 the 7 days of treatment started in the 4th postnatal week. In both experiments PAR acquisition was trained on the 28th day after birth (learning trial), PAR extinction testing started on the 29th day (retention trials). After applying a 0.5-mA footshock, rat pups treated with E021 within the first 7 days of life (Expt. 1) displayed significantly slower PAR extinction when compared to saline- and CERE-treated rats. In the 1 mA groups, significant differences in step-through latencies were measured between 0.9% saline- and E021-pretreated animals on retention day 11 and between saline and CERE on retention days 9 and 13. E021-treated rats of Expt. 2, receiving a footshock intensity of 0.5 mA, showed significant lower step-through latencies when compared to E021-treated rats of Expt. 1. In Expt. 2 no significant differences between treatment groups were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Early postnatal stimulation influences passive avoidance behaviour of adult rats.

In this study, the effects of stimulation on either postnatal days 1 to 7 or 21 to 27 on the passive avoidance reaction (PAR) of 3-month-old rats were examined. Animals received tactile or visual stimulation or tactile-visual stimulation for 10 min each day, and were trained at the beginning of the 4th month of life in a step-through apparatus using a footshock of 0.5 mA. Memory retention was measured 24, 48, 72, 96, and 120 h after the acquisition trial. Step-through latencies to enter the dark compartment and the total duration of stay in the illuminated compartment were recorded up to 200 s. Rats that received tactile or a combined tactile-visual stimulation during the 1st postnatal week displayed significantly longer PAR latencies and a longer duration of stay in the illuminated compartment compared to unstimulated control animals. Visual stimulation during the postnatal days 1 to 7 and 21 to 27 resulted in a longer duration of stay in the illuminated compartment. This effect, however, was more pronounced when stimulation was applied during the 1st postnatal week. Rats that received tactile stimulation during the 4th postnatal week showed decreased PAR performance for all measured parameters when compared to animals that received stimulation during the 1st postnatal week. Furthermore, combined tactile-visual stimulation during the 4th postnatal week led to a reduced duration of stay in the illuminated compartment when compared to the stimulation during the 1st postnatal week. These findings can be attributed to the higher degree of plasticity and to a heightened sensitivity to various stimuli in the 1st postnatal week. The results suggest that tactile, visual or combined tactile-visual stimulation have a long-lasting effect on the ability of adult rats to cope with stressful tasks.

Effects of postnatal stimulation on the passive avoidance behaviour of young rats.

We examined the effects of stimulation on either postnatal days 1-7 or 21-27 on passive avoidance reaction (PAR) of young rats. Animals received tactile or visual stimulation for 10 min each day, and were trained on postnatal day 28 in a step-through apparatus using a footshock of 0.75 mA for 2 s. Retention was tested on five consecutive days beginning on day 29. Memory retention was measured for each rat 24, 48, 72, 96 and 120 h after the acquisition trial. Step-through latencies to enter the dark compartment, time spent in the illuminated compartment and number of crossings of the light beam were recorded up to 200 s. Rats that received tactile or visual stimulation during the 4th postnatal week displayed significantly lower PAR latencies, a shorter stay in the illuminated compartment and a higher number of crossings of the light beam compared to rats treated during the 1st postnatal week. The untreated control group showed a rapid decline of PAR latencies. All experimental groups remained in the illuminated compartment longer and showed PAR latencies well above those of the control group. The differences became more pronounced when visual stimulation in the first postnatal week was used. The number of crossings of the light beam was significantly reduced by the treatment, with the exception of the experimental group stimulated visually in the 4th week. The behavioural changes induced by tactile or visual stimulation have a long-lasting effect in coping with a stressful task.

Approach towards an integrative drug treatment of Alzheimer's disease.

At present pharmacotherapy of Alzheimer's disease (AD) is limited to acetylcholinesterase inhibitors. These drugs produce small, but consistent improvements of memory and global function, some are also positively influencing activities of daily living. This therapeutic approach neglects the complexity of AD and the fact that most of the degenerating neurons are not cholinergic. Acetylcholinesterase inhibitors are symptomatic drugs, with no influence on disease progression. There is a need for disease modifying compounds, or preventive drugs. Data are indicating that vitamin E has some ability to influence the disease progression. The potency of non-steroidal anti-inflammatory drugs (NSAIDs) or estrogen as preventive agents has to be explored further in prospective clinical studies. The initial hope in the use of naturally occurring neurotrophic factors, like nerve growth factor, to rescue cholinergic neurons from degeneration and to restore cognitive function has been disappointed in first, small clinical studies. The peptidergic drug Cerebrolysin exhibiting neurotrophic stimulation, neuroimmunotrophic regulation and induction of BBB glucose transporter expression, might be able to address the pathological changes of AD at different levels simultaneously. In addition to an impressive preclinical database, results from 3 placebo-controlled, double-blind studies demonstrate significant improvements of cognitive performance, global function and activities of daily living in AD patients. In all studies persisting improvements, up to 6 months after drug withdrawal, indicate a powerful disease modifying activity.

The influence of Cerebrolysin and E021 on spatial navigation of 24-month-old rats.

In the present study the behavioural effects of Cerebrolysin (Cere), a peptidergic nootropic drug, and E021, the concentrated peptide fraction of Cere, were investigated in 24-month-old rats. Rats passing a pretest to exclude motor- and eye-deficits were treated with either drugs or saline as control (2.5 ml/kg, intraperitoneally i.p.) for 19 days. Animals were tested in a standard Morris water maze on day 16 after pretest for 4 consecutive days (test days 1-4), eight trials per day. No significant differences of escape latency between males and females were found, therefore, results were pooled. Both Cere and E021 treated rats showed significant lower escape latencies than saline treated controls on all four test days (p < 0.01). More pronounced effects of both drugs were found for female rats. Female rats showed no significant differences in motor activity whereas drug treated males swam quicker on test day 1 (Cere p < 0.01: E021 p < 0.05) and day 2 (Cere p < 0.01). In the present experiments it was demonstrated that i.p. administration of both Cere and E021 improves the spatial learning and memory of 24 month-old male and female rats.